- Email: [email protected]
Paediatric gastrointestinal pathology: selected topics
MINI-SYMPOSIUM: PAEDIATRIC PATHOLOGY
Paediatric gastrointestinal pathology: selected topics
Oesophagus During development, the foetal oesophagus is initially lined by ciliated stratified columnar epithelium which transforms over time through mucinous epithelium and finally to stratified squamous epithelium at around 20e25 weeks’ gestation. The squamous epithelium spreads out, beginning from the centre of the oesophageal tube. Islands of residual embryonic epithelium thus may be encountered if this process is not fully complete. Inlet (cervical) patch describes such an island, comprising gastric mucosa (fundic or, less commonly, antral type) flanked by, occasionally inflamed, squamous mucosa in the upper third of the oesophagus. A pink, soft, flat to raised, patch is seen. Oesophageal rings, webs and stenoses may also occur.
Denise Hiu-Jun Tao Bhumita Vadgama
Abstract The spectrum of paediatric gastrointestinal pathology is very wide and encompasses some diseases which overlap with those also seen in adult populations (e.g. chronic inflammatory bowel disease), whilst others are almost exclusive to children (e.g. necrotising enterocolitis). Selected topics in non-neoplastic paediatric gastrointestinal pathology are discussed. In this article, we briefly outline some specific gastrointestinal entities which may rarely be encountered in adult surgical pathology practice, including aspects of inflammation, infection, congenital abnormalities and those related to prematurity. Differences of certain pathologies between adults and children presenting with the same disease are highlighted.
Reflux oesophagitis Gastro-oesophageal reflux (GOR) describes backwards flow of gastric or, rarely in children, duodenal contents into the oesophagus. GOR disease (GORD) can present any time in childhood but is particularly common during infancy, due partly to an immature lower oesophageal sphincter. Frequent effortless regurgitation is very commonly noted but other non-specific symptoms leading to presentation include prolonged crying, irritability, vomiting and failure to thrive (FTT). Feeding refusal, poor growth, abdominal pain and chronic cough are more frequent in toddlers through to adolescents. Haematemesis is occasional. Presentation in adults is classically of heartburn, dysphagia and chest pain, which comprise less than 15% of presenting symptoms in older children.2 Infantile reflux usually resolves within two years, however, persistent reflux is not uncommon when presenting in older children. Risk of GORD is increased in children with neurological impairment, cystic fibrosis (CF), bronchopulmonary dysplasia and post oesophageal atresia (OA) or tracheo-oesophageal fistula (TOF) repair. Complications of chronic GOR include oesophageal stricture, mucosal ulceration, bleeding and Barrett’s metaplasia. Features on microscopy are similar to those seen in adults and are not specific but include basal hyperplasia (>15e20% of the mucosal depth), elongation of subepithelial papillae (much more than 50%), capillary congestion, basal layer spongiosis, acanthosis and balloon cells. Intraepithelial lymphocytes (IELs) and eosinophils may be present (latter more significant if >6 per high power field (HPF)). Features can be patchy. The gastric cardia can be inflamed in GORD. Clinical correlation and with pH studies is important as a large proportion of patients with GOR show normal histology.
Keywords congenital; duplication cyst; enterocolitis; eosinophils; gastritis; gastrointestinal; pediatric
Introduction The spectrum of gastrointestinal tract (GIT) disorders seen in paediatric patients is wide and the pathology differs partly from those seen in general adult pathology, with some overlapping areas. Pathologies related to congenital anomalies and immature development comprise a larger fraction than in adult surgical pathology. Neoplasms are uncommon. It is not possible to cover all aspects of paediatric gastrointestinal pathology in this article. The reader is thus referred to detailed review articles discussing paediatric gastrointestinal neoplasia, polyps, dysmotility disorders including Hirschsprung’s disease, and enteropathies of infancy including eosinophilic gastroenteritis, published in a specific paediatric GIT and liver mini symposium previously in this journal.1 This article is aimed at providing a brief overview of some of the other main gastrointestinal conditions encountered in paediatric surgical pathology and noting differences in those disorders also commonly seen in adult pathology. Endoscopic biopsy findings by site will be discussed first, followed by congenital anomalies and other lesions submitted as larger resection specimens.
Eosinophilic oesophagitis (EO) Two decades ago it was noticed that some children with refluxtype symptoms, who did not improve on anti-reflux treatments, showed very prominent mucosal eosinophilia. Atopic disorders were more prevalent within this subgroup; hence EO is also known as allergic oesophagitis. Caucasians, male gender and atopy are established risk factors (approximately 70% of patients or their family members have other atopic disorders3,4). pH studies are normal. In childhood, more EO patients present before 10 years of age. Similar symptoms as GORD occur, but a higher proportion of children also complain of “food getting stuck”. Endoscopic findings of linear furrowing/wrinkling or ‘trachealisation’ are more suggestive of EO. Microscopic features are
Denise Hiu-Jun Tao BSc (Hons) MSc MBBS, Histopathology Speciality Registrar, Southampton General Hospital, Southampton, UK. Conflicts of interest: none declared. Bhumita Vadgama MBChB FRCPath, Consultant Paediatric Pathologist, Southampton General Hospital, Southampton, UK. Conflicts of interest: none declared.
DIAGNOSTIC HISTOPATHOLOGY xxx:xxx
1
Ó 2019 Published by Elsevier Ltd.
Please cite this article as: Hiu-Jun Tao D, Vadgama B, Paediatric gastrointestinal pathology: selected topics, Diagnostic Histopathology, https:// doi.org/10.1016/j.mpdhp.2019.06.002
MINI-SYMPOSIUM: PAEDIATRIC PATHOLOGY
identified in children. Heavy neutrophilic inflammation is typical, often with a degree of ulceration and epithelial necrosis in HSV infection. Multinucleated giant cells are occasionally seen. Intranuclear HSV inclusions may be evident in the squamous epithelium around the ulcer edge, whereas CMV inclusions are usually located in stromal or endothelial cells at the base of ulcers. Candida pseudo-hyphae can be recognised in the epithelium and within fibrinopurulent exudate, which can be confirmed with Grocott or PAS stains. Rarely, other organisms may be suspected, e.g. Aspergillus, EpsteineBarr virus (EBV) and Varicella-Zoster virus.
similar to those seen in GORD but intraepithelial eosinophils are usually much higher (>20 per HPF). Although cut-off numbers are stated, generally speaking, clinically significant numbers tend to be obvious microscopically. Correlation with the pattern of infiltration, distribution (throughout the oesophageal length favours EO) and comparison with previous biopsies may be more helpful as disease can be patchy. Superficial layering of eosinophils, aggregation, degranulation and eosinophil-laden surface slough are features which favour EO (Figure 1). Lymphocytes may be slightly increased and activated mast cells seen, but neutrophils are not readily identified. Basal cell hyperplasia is often prominent and fibrosis of the lamina propria may be present. EO may be secondary to, or associated with, eosinophilic gastroenteritis or a peripheral eosinophilia.
Other Other causes of oesophagitis in children include Crohn’s disease (CD), ingestion of toxic or caustic substances (e.g. batteries) and drug-induced oesophagitis. The latter includes chemotherapy effects and impaction of tablets. Some dermatopathies can affect the oesophageal mucous membranes (e.g. Stevens-Johnson syndrome).
Barrett’s oesophagus (BO) BO is defined as columnar intestinal metaplasia replacing the native oesophageal squamous mucosa. BO is rare in children and is almost exclusively seen in those with long-standing GORD. Prevalence is reported between 0.3 and 4.8%.5 In some countries, diagnosis requires the presence of goblet cells on histology (e.g. as defined by the American Society of Gastroenterology); however, this is not mandatory in the UK, under guidelines published by the British Society of Gastroenterology.5,6 Several types of columnar lined mucosa have been described in BO, including intestinal, gastric fundal and gastric cardia types. The presence of native oesophageal structures on histology (e.g. submucosal ducts) may help confirm origin from the oesophagus in columnar mucosa. However, very few biopsies tend to demonstrate these. The exact site of biopsy has to be clarified with the gastroenterologist for a diagnosis of BO. Goblet cells have characteristic morphology but Alcian blue stain (at pH 2.5) may help by highlighting the acid mucin within them. Dysplasia in paediatric BO is exceedingly rare.
Stomach Gastritis is frequently seen in children but remains more common in adults. Atrophic gastritis and gastric malignancy, dysplasia or metaplastic conditions are diagnosed extremely rarely in the paediatric population. The diagnosis of mild gastritis can be subjective. Microscopy of a normal paediatric stomach biopsy demonstrates scanty dispersed chronic inflammatory cells. Lymphocyte aggregates should be small, very infrequent, and located mainly in the deeper mucosa. Eosinophils are sparse.7 Infectious gastritis Helicobacter pylori (HP) gastritis is common in adults and histopathology is well known. It remains the most common cause of gastritis in children where an aetiology is identifiable. HP causes acute and chronic active gastritis often with prominent germinal centres in lymphoid follicles. The latter are more frequently seen in children. Activity tends to concentrate around the neck of glands and a lymphocytic gastritis type picture may be seen. Chronic inflammation in biopsies can persist for up to several years after treatment, but acute changes tend to disappear by two months.7 Helicobacter heilmannii is prevalent in household pets and some farm animals and causes gastritis uncommonly in children. Inflammation is less intense compared to HP infection and the gastric antrum is involved in nearly all cases. The organism is longer and more spiralled in appearance. Other infectious aetiologies are less frequently seen in paediatric gastric biopsies. CMV, HSV, mycobacteria, and fungal infections may rarely be detected in biopsies from immunocompromised patients. Bacterial gastritis is scarcely biopsied. A third of patients with clinical hypertrophic gastropathy have associated CMV infection. As classic Menetrier disease is exceedingly rare in children, if enlarged gastric folds are noted at endoscopy, screening for CMV infection should be considered. Hypertrophic gastropathy is occasionally seen in eosinophilic gastritis, HP gastritis, and gastric lymphoma. Microscopy features of hypertrophic gastropathy include oedema, a mixed chronic inflammatory infiltrate, focal atrophy, foveolar
Infectious oesophagitis Infectious oesophagitis is uncommon except in debilitated or immunocompromised children. White plaques seen at endoscopy are suspicious for fungal infection and discrete ulcers may be visible in herpes simplex virus (HSV) infection. Candida, HSV and cytomegalovirus (CMV) are the most common organisms
Figure 1 Eosinophilic oesophagitis demonstrating degranulation and clustering of eosinophils towards the luminal surface (superficial layering).
DIAGNOSTIC HISTOPATHOLOGY xxx:xxx
2
Ó 2019 Published by Elsevier Ltd.
Please cite this article as: Hiu-Jun Tao D, Vadgama B, Paediatric gastrointestinal pathology: selected topics, Diagnostic Histopathology, https:// doi.org/10.1016/j.mpdhp.2019.06.002
MINI-SYMPOSIUM: PAEDIATRIC PATHOLOGY
hyperplasia and reduced numbers of parietal and chief cells.7 In neonates, marked antral foveolar hyperplasia has been described after the use of prostaglandins to maintain a patent ductus arteriosus.8
Caucasian populations. Nearly all patients are HLA-DQ2 or HLADQ8 positive. There is an approximate 75% concordance rate in identical twins. Diagnosis is primarily a clinicopathological process after biopsy examination. In the UK, duodenal biopsy is not necessary in the symptomatic patient if the serum IgA anti-tissue transglutaminase (tTG) level is >10x the upper reference limit, they are HLA-DQ2 or DQ8 haplotype positive, and the IgA antiendomysial antibodies (EMA) are raised.11 The characteristic histological features are well reported e.g. villous atrophy, excess intraepithelial lymphocytes (IELs), increased background chronic inflammation and crypt hyperplasia. Marsh scoring of severity of changes is used in some centres. Minor neutrophilic activity may be seen, especially in young children. When small bowel architecture and IELs are within normal limits, clustering of IELs at the villus tip and a ‘crescendo’ pattern upward along the villus sides may be early clues; however these findings are not diagnostic. Mimics of GSE in children include cow’s milk protein (CMP) allergy, which is one of the commonest food allergies in children and can present with gastric, small bowel or colonic symptoms. Similar changes may be seen with soya, egg and other food allergens. Post-enteritis enteropathy can present as malabsorption in a child after resolution of an acute episode of viral gastroenteritis. Autoimmune enteropathy can cause marked villous atrophy and inflammation as well. Crypt apoptotic activity is increased.1,7 See Table 1 for more histopathological differential diagnoses.
Drug effects Chemical/reactive gastropathy is less common in children but some similar aetiologies to adults exist, e.g. bile reflux and drugs, particularly NSAIDs in older children. Steroids, NSAIDs and oral iron can cause erosions, with regenerative epithelial change in adjoining mucosa. Chronic inflammation occurs particularly in the gastric body with proton pump inhibitor (PPI) therapy, more so than in the antrum. The parietal glands appear dilated and are lined by bumpy protuberant cells, resembling fundic gland polyps. Clear cell change is seen with prolonged use. Lymphocytic gastritis Lymphocytic gastritis describes an excess of gastric intraepithelial CD3þ CD8þ lymphocytes (>25 per 100 epithelial cells) on a background of chronic inflammation within the lamina propria. Association with coeliac disease is well known and a wide range in prevalence, up to 40%, is reported. It can be seen in CD, some cases of HP gastritis, and rarely autoimmune conditions. Granulomatous gastritis Non-necrotising granulomas in stomach biopsies of CD patients constitute the largest group with this morphology in children. Other systemic causes include mycobacterial or Histoplasma infection and, rarely, chronic granulomatous disease (CGD), granulomatosis with polyangiitis, sarcoidosis, common variable immunodeficiency (CVID) and Langerhans cell histiocytosis.
Infectious enterocolitis Acute bacterial (more commonly campylobacter jejuni, escherichia coli, shigella) and viral (e.g. rotavirus, Norwalk virus, astrovirus) infections are rarely biopsied and are diagnosed mainly on stool culture ELISA or PCR. Yersinia enterocolitica can mimic IBD or appendicitis by causing an inflammatory mass near the ileocaecal junction. Adenoviral infection can occur in the immunocompromised child10 and can cause a lead point for intussusception by eliciting marked lymphoid hyperplasia. CMV is not uncommonly seen and can mimic necrotising enterocolitis (NEC) by causing severe haemorrhagic colitis with scattered discrete ulcers. Microscopy features of giardiasis and cryptosporidium infection are summarised in Table 1.
Other In allergic/eosinophilic gastritis, eosinophils infiltrate the gastric mucosa especially within the antrum. This may be associated with hypersensitivity, food allergy, atopic disorders and autoimmune conditions. Serum IgE levels may be raised. It forms part of eosinophilic gastroenteritis.1,7 Gastric eosinophils may be increased also as part of chronic inflammatory bowel disease (IBD) and rarely can be associated with parasitic infection, drug reaction or connective tissue disorders. Gastric polyps are rare in the paediatric population although juvenile polyps and Peutz-Jeghers polyps do occur in the stomach.1 Fundic gland polyps may be seen in Familial Adenomatous Polyposis (FAP) and can resemble the changes associated with PPI use (see above). Further investigation for FAP may need to be considered by clinicians if there is a negative drug history for PPIs. Fundic gland polyps are usually very small, located in the body or fundus and show foveolar hyperplasia and dilated cystic glands but lack parietal cell hyperplasia.
Immunodeficiency (ID) ID of the GIT in children is a complex expanding group of disorders which can be classified into primary or secondary aetiologies. There are some overlapping features with autoimmune enteropathy; however a paucity of lamina propria plasma cells is the main suggestive feature of ID. Examples of primary diseases include selective IgA deficiency, CVID, X-linked agammaglobulinaemia and severe combined immunodeficiency (SCID). SCID presents in infancy and may be fatal without bone marrow transplant.10 IgA deficiency is the most common ID (incidence up to 2:1000) and is associated with other autoimmune processes e.g. pernicious anaemia and GSE. It is also increased in families with CVID. There are some histological similarities to GSE except for the lack of plasma cells. With IgA deficiency, screening for GSE should be carried out with IgG-linked antibodies instead of IgA-tTG. Chronic granulomatous disease (CGD) is due to NADPH oxidase pathway mutations leading to ineffectual ‘oxidative burst’ during phagocytosis, with 60% of cases showing X-linked
Small and large intestines Detailed descriptions regarding infantile enteropathies, eosinophilic gastroenteritis and Hirschsprung’s disease are available in standard paediatric pathology textbooks and review articles.1,5,7,9,10 Coeliac disease/gluten sensitive enteropathy (GSE) GSE, which is a T-cell related immune response, is the most common small bowel mucosal disorder causing malabsorption in
DIAGNOSTIC HISTOPATHOLOGY xxx:xxx
3
Ó 2019 Published by Elsevier Ltd.
Please cite this article as: Hiu-Jun Tao D, Vadgama B, Paediatric gastrointestinal pathology: selected topics, Diagnostic Histopathology, https:// doi.org/10.1016/j.mpdhp.2019.06.002
MINI-SYMPOSIUM: PAEDIATRIC PATHOLOGY
Mimics of coeliac disease in small bowel biopsies from children5,7,9,10 Villus architecture
Cow’s milk protein/other food allergy
Intraepithelial Lamina propria lymphocytes chronic inflammation
Patchy mild to moderate Mildly atrophy increased
Increases in Other features Neutrophils (PMNs)/ eosinophils (Eos) [ Eos, may be mild No [ PMNs
Patchy, mild
Non-IgE mediated Symptoms can be mild to severe, including PR bleeding, protein losing enteropathy, FTT, constipation. Post-enteritis Patchy variable atrophy Usually normal Patchy, mild to Not usually Clinical history of recent infection enteropathy moderate increased May last weeks to months after initial viral infection has resolved Crohn’s disease Possible villus blunting May be Variable, patchy. Patchy [ of both, Non-necrotising granulomata with possible glandular increased may see glandular architectural distortion abscesses. [ Eos more often in deep mucosa. Autoimmune Partial to total villous Minor if Variable, Sometimes [ of Seen in infants or young children more, with enteropathy atrophy with possible present predominantly both variable severity of pathology glandular destruction lymphocytes and Mimics GVHD Reduced goblet cells with plasma cells May have other autoimmunity e.g. DM type 1 increased Can be associated with IPEX syndrome cryptal apoptosis (Immunodysregulation, Polyendocrinopathy, Enteropathy; X-linked): with FOX3P mutations Giardia lamblia Commonly normal Occasional Mild if present Sometimes minor Biopsy may be entirely normal mild excess [of both Surface organisms resemble ‘falling leaves’ Cryptosporidium Variable mild to Not typical Mild, may be mixed Mixed History of note: occasionally severe acute and chronic Inflammation with Immunocompromised patients, travel history, atrophy inflammatory cells occasional exposure to farm animals cryptitis Stool examination for parasites Organisms resemble ‘blue beads’ on surface epithelium on microscopy CVID Variable atrophy Possible Nodular lymphoid Sometimes acute Low serum levels of IgA, IgM and IgG hyperplasia with inflammation with Can mimic autoimmune enteropathy plasma cell paucity [ of both Occasionally granulomata seen Table 1
inheritance. CGD patients are prone to infection by catalasepositive organisms, e.g. candida and staphyloccocus aureus. Histological features mimic IBD and can show patchy inflammation anywhere in the GIT, including the mouth. Granulomas may be seen and the presence of light orange-brown pigmented macrophages is highly suggestive (Figure 2). Chronic mucocutaneous candidiasis is a T-cell related disorder presenting in infancy, and which can lead to polyendocrinopathy.7,9 Graft versus host disease (GVHD) occurs more commonly after bone marrow or stem cell transplant, affecting the GIT in nearly half of acute presentations.10 Acute GVHD typically shows increased epithelial apoptotic debris deep within the crypts. There may be villous atrophy and features may partly resemble autoimmune enteropathy. Eosinophils can be seen. However, changes may be patchy so multiple biopsies are advised. As mycophenolate induced injury can show similar features, clinical correlation is essential (Figure 3).
DIAGNOSTIC HISTOPATHOLOGY xxx:xxx
Colitis Chronic IBD constitutes a large proportion of the workload (diagnostic/disease surveillance biopsies and resections) in paediatric GIT pathology. The main clinical and pathological features, both on macroscopic inspection and on microscopy, greatly mirror those seen in adults and will not be discussed. Hence only specific differing points will be mentioned. Nearly one-fifth of IBD patients are diagnosed before 15 years of age and the diagnosis of CD has slowly risen over 40 years. Clinical presentation is mostly similar to adults (e.g. diarrhoea, abdominal pain) but children can present with FTT or delayed onset of puberty. In children, both ulcerative colitis (UC) and CD are most commonly diagnosed in adolescence, however in UC, 3% are aged 5 years or less.5,7,9 In UC, children more often present with extensive colonic disease than adults. Backwash ileitis and pancolitis is seen more frequently in children and can be more extensive. Patients with UC may present with a caecal patch and skip lesions in the
4
Ó 2019 Published by Elsevier Ltd.
Please cite this article as: Hiu-Jun Tao D, Vadgama B, Paediatric gastrointestinal pathology: selected topics, Diagnostic Histopathology, https:// doi.org/10.1016/j.mpdhp.2019.06.002
MINI-SYMPOSIUM: PAEDIATRIC PATHOLOGY
may even lead to reversal of early chronic features. In severe ulcerating disease, extension into the submucosa may occur in UC. Upper GIT involvement in UC is also more frequent in children than adults, commonly chronic gastritis, but minor activity may also be seen. CD in children presents with pancolitis in nearly half of cases (adults about 20%) but stricturing or fissuring disease is less common. Around 40% present with ileal disease alone. Granulomas are identified more often in paediatric biopsies than in adult cases.5
Congenital surgical disorders and abnormalities of the gastrointestinal tract There are numerous congenital surgical disorders and abnormalities of the GIT which cannot all be covered in this article. We present a few (other than congenital dysmotility disorders) that can result in a surgical specimen. Oesophageal resections are uncommon and occasional specimens from acquired oesophageal stenoses (e.g. sequelae of caustic or thermal injury) may be submitted, showing submucosal fibrosis and possible non-specific chronic inflammation.
Figure 2 Chronic granulomatous disease can mimic Crohn’s disease. Patchy inflammation, abscesses and granulomas may be seen. Light orange-tan finely pigmented macrophages (seen here) are typically identified in the deeper lamina, more often in the less inflamed areas.
appendix. Focal active colitis only may be noted in rectal biopsies more often in children with UC at first presentation. As chronic features are absent in these rectal biopsies with focal activity, the term “relative rectal sparing” is applied. Relative rectal sparing can be seen initially in just less than a quarter of children who go on to be diagnosed with UC and thus focal active colitis is more ominous toward IBD in children than in adults.5,12 Treatment
Tracheo-oesophageal fistula (TOF) and oesophageal atresia (OA) TOF is an anomalous fistulous connection between the proximal and/or distal oesophagus and the tracheobronchial tree. OA and TOF most often occur together, in around 1 in 3000 births, resulting from variable incomplete division of the primitive foregut in the fourth and fifth weeks of gestation. There may be associated maternal polyhydramnios. OA without TOF is suggested on prenatal ultrasound screening by a small stomach with no gas bubble. An accompanying TOF can diminish these features. TOF/OA are classified into five main types dependent on the presence of OA only (more common in trisomy 21); OA with variably connected TOF; and TOF only. By far the most prevalent (85%) is of an upper oesophageal pouch, with a distal TOF, entering close to the carina, thus leaving a relatively short gap, more amenable to repair. Neonates require emergency surgery as choking, respiratory distress, or aspiration can ensue. The tracheal or bronchial fragments often show squamous metaplasia but the oesophageal pouch (more commonly submitted) may show abnormal mucous glands, disorganised muscular layers or cartilage.10,13 Approximately one half of infants with OA/TOF have associated congenital anomalies, frequently of midline structures. Cardiac abnormalities are found in about 30%. GIT anomalies (e.g. duodenal atresia or diaphragmatic hernia) are seen in 20% and approximately 25% of infants demonstrate VACTERL association syndrome (vertebral, anorectal malformation, cardiac, tracheo-oesophageal fistula, renal anomaly and limb defects). 6 e10% have associated chromosomal abnormalities such as trisomy 13, 18, or 21.13,14 Long-standing GOR is a common complication in many, with higher risk of BO. Duplication cysts Oesophageal duplication cyst is rare but more often lies adjacent to the lower half of the thoracic oesophagus. It may be separate or share part of the main oesophageal wall. The layers of the
Figure 3 In GVHD crypt apoptotic activity is prominent with variable cryptal debris and inflammation (as seen here). Crypt dropout may be seen. Severe cases show ulceration and surface denudation. Regenerative changes may occur later. Organisms of opportunistic infections should be bourne in mind.
DIAGNOSTIC HISTOPATHOLOGY xxx:xxx
5
Ó 2019 Published by Elsevier Ltd.
Please cite this article as: Hiu-Jun Tao D, Vadgama B, Paediatric gastrointestinal pathology: selected topics, Diagnostic Histopathology, https:// doi.org/10.1016/j.mpdhp.2019.06.002
MINI-SYMPOSIUM: PAEDIATRIC PATHOLOGY
wall of a duplication cyst are mainly normal and the lining mucosa may be stratified squamous or columnar, with or without cilia. A bronchogenic cyst is a differential diagnosis in the thorax. If ciliated epithelium is present, the differential may be difficult. Bronchogenic cysts tend to lack an organised muscularis propria, and cartilage or respiratory glands can be present. Occasionally, a gastroenteric cyst may add to the confusion in the mediastinum. They usually occur in the right posterior mediastinum. Some extend into the spinal canal (termed neuroenteric cysts). The spectrum of these neuroenteric remnants (split notochord syndrome) encompass gastrointestinal diverticula, fistulae, cysts, dorsal dermoid cysts or sinuses and cords. They extend from the dorsal midline GIT, upward and, possibly to the spinal cord or posterior skin, undergoing segmental obliteration along its path. Neuroenteric cyst linings show potentially any gastrointestinal epithelia (site dependent) and may include neuroglial or meningeal tissues.7 Gastric duplications lie more frequently along the greater curvature. Duplication cysts are most common in the small intestine area. Similar well-organised transmural features are noted with varying gastric, intestinal to simple epithelial linings evident (Figure 4).
Malrotation results from an aberration at any point during the return and fixation of the externally rotated GIT back into the body cavity (gestational weeks 10e11). Malrotation and Meckel’s diverticulum are risk factors for volvulus and intussusception. Malrotation is frequently associated with other abnormalities, e.g. ileal atresia and Hirschsprung’s disease. Intestinal atresia and stenosis Atresia is when the lumen is interrupted. Atresias of the colon and stomach are rare; hypertrophic pyloric stenosis is the main form of congenital stenosis seen in the stomach. The most common sites of atresia affect the duodenum, proximal jejunum and distal ileum. The former is seldom sent as a surgical specimen. Multiple small bowel atresias occur in 10% of patients. Jejuno-ileal atresias have been classified into 5 types, ranging from just membranous atresia (type I) where the bowel wall and mesentery are intact, to multiple intermittent atresias along a length of bowel (type IV). The most common form is type III (two blind ends are present without an intervening fibrous cord). Atresias are mainly considered to be due to intrauterine vascular events leading to ischaemia, infarction, absorption or fibrosis. Histology reveals fibrosis and calcification obliterating the lumen, mucosa and submucosa but a residual muscularis propria is often recognisable. There may be luminal granulation tissue. Features suggestive of CF should be sought (see below). Anorectal malformations can be complex. Small fragments from the surgical repair are often received, showing skin, anorectal mucosa, urothelium to vaginal squamous mucosa.
Exomphalos and vitellointestinal maldevelopment Exomphalos (omphalocoele) occurs when the midline developmental anterior abdominal wall defect fails to close. Viscera may remain bulging into the sac if normal physiological return into the abdominal cavity is disturbed. The sac may be excised and comprises amnion, parietal peritoneum, and connectives tissues. The umbilicus inserts into the dome of the sac. Faulty obliteration of all or part of the vitellointestinal (omphalomesenteric) duct during embryonic GIT development can result in a fistula with the ileum, Meckel’s diverticulum, and fibrous cords or distally as omphalomesenteric cysts, fistulae or umbilical granulomas. Remnants can show various types of GIT mucosa or even pancreatic heterotopia. Meckel’s diverticulum is a frequently submitted specimen; occurring in 2% of the population and constituting 90% of all omphalomesenteric duct related abnormalities. Presence of gastric and pancreatic heterotopia with potential ulcerative sequelae is well known.7,9
Figure 4 Duplication cyst with normal native bowel wall (upper right). The duplication cyst (lower right) shows its own well-organised wall (including both layers of the muscularis propria), merging with the native bowel wall (left). In this case the cyst is lined by markedly attenuated flattened epithelium.
DIAGNOSTIC HISTOPATHOLOGY xxx:xxx
Figure 5 Ileum of neonate showing early mucosal haemorrhagic necrosis. Note the deep crypt lumina expanded by densely eosinophilic thick secretions. This is suggestive of cystic fibrosis.
6
Ó 2019 Published by Elsevier Ltd.
Please cite this article as: Hiu-Jun Tao D, Vadgama B, Paediatric gastrointestinal pathology: selected topics, Diagnostic Histopathology, https:// doi.org/10.1016/j.mpdhp.2019.06.002
MINI-SYMPOSIUM: PAEDIATRIC PATHOLOGY
Single juvenile polyps (not part of juvenile polyposis syndrome) are commonly rectal in site, cause PR bleeding in young children and comprise granulation tissue, dilated glands and lamina propria inflammation.
Disorganised muscle bundles and stroma with non-specific inflammation may be seen. Necrotising enterocolitis (NEC) NEC is the most common reason for emergency surgery in the newborn, primarily affecting premature infants. The exact aetiology remains unclear but translocation of microorganisms, cytokine activation and immature immunity of the bowel are just some of the multiple factors thought to contribute to its pathogenesis. The main risk factors are prematurity, bacterial colonisation and formula feeding. Recently it has been identified that the premature intestinal epithelium is predisposed to mounting an exaggerated inflammatory response to colonizing bacteria, leading to mucosal destruction (e.g. by increased enterocyte apoptosis) and impaired mesenteric perfusion. This heightened response is partly due to the already increased innate TLR4 (tolllike receptor 4) expression on the premature infants’ enterocytes. Gram negative bacteria can further activate TLR4, perpetuating the reaction. Reviews suggest that potential inhibitors blocking TLR4 may help in the future together with modifying other identified growth factors.15 Vitamin D is a regulator of TLR4. No specific treatment for NEC exists. When resection becomes necessary, potential long term sequelae are severe and include short gut syndrome, strictures and malabsorption. Small bowel NEC is seen more frequently than of the colon. On macroscopy, the bowel wall can show thinning, mucosal congestion and discolouration or perforation. NEC is characterised by coagulative and haemorrhagic mucosa and varying mural necrosis. It may be patchy in distribution or of confluent extent. Bacteria may be seen on the mucosal surface and scattered gas-filled cystic spaces may be present in the wall (pneumatosis intestinalis). The presence of ganglion cells should be confirmed, as in term infants, NEC may be a presentation of Hirschsprung’s disease.
Practice points C
C
C
C
C
C
C
C
Meconium ileus and peritonitis Meconium ileus is obstruction due to luminal impacted meconium debris, more common in the ileum or proximal colon of low birth weight infants. It is associated with CF in a significant proportion. 10e15% of babies with CF will have neonatal meconium ileus. Ileus is usually treated medically but a thick green luminal plug may be noted at resection and, on microscopy, dense eosinophilic material filling crypts is suspicious of CF (Figure 5). Exclusion of Hirschsprung’s disease is needed as it is a clinical mimic for ileus. If intra-uterine intestinal perforation occurs, the released meconium elicits a severe peritoneal reaction with inflammation, fibrosis, calcification and sometimes a foreign body type reaction. If the inguinal canal is still patent at the time of intra-uterine perforation, meconium periorchitis may also develop.
C
A REFERENCES 1 Mini-symposium: paediatric gastrointestinal and liver pathology. In: Bateman A, Mead Z, eds. Diagn Histopathology 2015; 21: 217e60. 2 Treem WR, Davis PM, Hyams JS. Gastroesophageal reflux in the older child: presentation, response to treatment and long-term follow-up. Clin Pediatr 1991; 30: 435e40. 3 Philpott H, Nandurkar S, Royce SG, Thien F, Gibson PR. Risk factors for eosinophilic esophagitis. Clin Exp Allergy 2014; 44: 1012e9. 4 Straumann A, Aceves SS, Blanchard C, et al. Pediatric and adult eosinophilic esophagitis: similarities and differences. Allergy 2012; 67: 477e90.
Other Intussusception and volvulus show features of haemorrhagic necrosis. The former occurs mainly near the ileocaecal junction and is seen more often in infants. Mass lesions should be excluded in the older child. Lead points can include pancreatic heterotopic nodules, polyps, small duplications or mucosal lymphoid hyperplasia (consider adenovirus). Rarely, GIT lymphoma may be seen.
DIAGNOSTIC HISTOPATHOLOGY xxx:xxx
EO can be a patchy disease. Ideally examine multiple multi-site biopsies along the oesophagus. Do not rely on eosinophil numbers alone. Examine the overall pattern and distribution of infiltrate in individual biopsies Mild basal hyperplasia and elongation of subepithelial papillae can be seen in biopsies close to the squamocolumnar junction in patients, even without GORD10 Persistent embryonic surface columnar epithelium, at either end of the oesophagus, may be seen especially in premature babies but should disappear by early infancy e this is different to inlet patch of heterotopic gastric mucosa in upper oesophagus At the gastro-oesophageal junction and gastric cardia of neonates and young children, acid mucins can occur within the columnar epithelium without goblet cells e beware of over-diagnosis of BO16 Prominent Brunner’s glands in D1 biopsies can distort architecture and cause mild villous blunting e this is not true atrophy Always consider the differential diagnosis of CGD in GIT biopsies for IBD from young boys with granulomatous inflammation e look for faintly pigmented macrophages in deep lamina propria, see Figure 2 Compared to adults, children with only focal active colitis in their initial GIT biopsies are much more likely to be diagnosed with IBD at a later stage e although not diagnostic, do not dismiss this finding; communicate with the clinicians In children, chronic and chronic active inflammation in the upper GIT is seen much more frequently in CD and even UC, compared to adult populations. Therefore, with upper GI inflammation alone, in the absence of granulomas CD should not be definitively diagnosed Be aware of dual pathologies (e.g. Giardia in a biopsy with features of CVID or other ID); or of masking pathologies (e.g. NEClike features in neonatal CF, see Figure 5)
7
Ó 2019 Published by Elsevier Ltd.
Please cite this article as: Hiu-Jun Tao D, Vadgama B, Paediatric gastrointestinal pathology: selected topics, Diagnostic Histopathology, https:// doi.org/10.1016/j.mpdhp.2019.06.002
MINI-SYMPOSIUM: PAEDIATRIC PATHOLOGY
IR, et al. European soci11 Husby S, Koletzko S, KorponayeSzabo ety for pediatric Gastroenterology, hepatology, and nutrition guidelines for the diagnosis of coeliac disease. J Pediatr Gastroenterol Nutr 2012; 54: 136e60. 12 Scudiere JR, Maitra A, Montgomery EA. Selected topics in the evaluation of pediatric gastrointestinal mucosal biopsies. Adv Anat Pathol 2009; 16: 154e60. 13 Polydorides AD. Alimentary canal. In: Putman AR, Thompson KS, eds. Diagnostic pathology: nonneoplastic pediatrics. Amirsys, 2013. 8.4-8.12. 14 Shaw-Smith C. Oesophageal atresia, tracheo-oesophageal fistula, and the VACTERL association: review of genetics and epidemiology. J Med Genet 2006; 43: 545e54. ~o DF, Sodhi CP, Hackam DJ. Necrotizing enterocolitis: new 15 Nin insights into pathogenesis and mechanisms. Nat Rev Gastroenterol Hepatol 2016; 13: 590e600. 16 Ellison E, Hassall E, Dimmick JE. Mucin histochemistry of the developing gastroesophageal junction. Pediatr Pathol Lab Med 1996; 16: 195e206.
5 Brundler M-A, Borralho P, Karikoski R, Domizio P, Cohen MC. Gastrointestinal tract. In: Cohen MC, Scheimberg I, eds. Essentials of surgical pediatric pathology. Cambridge University Press, 2014; 210e50. 6 Fitzgerald RC, Di Pietro M, Ragunath K, et al. British Society of Gastroenterology guidelines on the diagnosis and management of Barrett’s oesophagus. Gut 2014; 63: 7e42. 7 Russo P, Ruchelli ED, Piccoli DA, eds. Pathology of pediatric gastrointestinal and liver disease. New York: Springer-Verlag, 2004. 26-27 and 47-87. 8 Peled N, Dagan O, Babyn P, et al. Gastric-outlet obstruction induced by prostaglandin therapy in neonates. N Engl J Med 1992; 327: 505e10. 9 Gastrointestinal pathology. In: Sebire NJ, Malone M, Ashworth M, Jacques TS, eds. Diagnostic pediatric surgical pathology. Churchill Livingstone Elsevier, 2009; 529e600. 10 Hart J, Wilcox R, Weber CR. The gastrointestinal tract. In: Stocker JT, Dehner LP, Husain AN, eds. Stocker and Dehner’s paediatric pathology. Philadelphia: Lippincott Williams & Wilkins, 2011; 586e627.
DIAGNOSTIC HISTOPATHOLOGY xxx:xxx
8
Ó 2019 Published by Elsevier Ltd.
Please cite this article as: Hiu-Jun Tao D, Vadgama B, Paediatric gastrointestinal pathology: selected topics, Diagnostic Histopathology, https:// doi.org/10.1016/j.mpdhp.2019.06.002
Paediatric gastrointestinal pathology: selected topics
Oesophagus During development, the foetal oesophagus is initially lined by ciliated stratified columnar epithelium which transforms over time through mucinous epithelium and finally to stratified squamous epithelium at around 20e25 weeks’ gestation. The squamous epithelium spreads out, beginning from the centre of the oesophageal tube. Islands of residual embryonic epithelium thus may be encountered if this process is not fully complete. Inlet (cervical) patch describes such an island, comprising gastric mucosa (fundic or, less commonly, antral type) flanked by, occasionally inflamed, squamous mucosa in the upper third of the oesophagus. A pink, soft, flat to raised, patch is seen. Oesophageal rings, webs and stenoses may also occur.
Denise Hiu-Jun Tao Bhumita Vadgama
Abstract The spectrum of paediatric gastrointestinal pathology is very wide and encompasses some diseases which overlap with those also seen in adult populations (e.g. chronic inflammatory bowel disease), whilst others are almost exclusive to children (e.g. necrotising enterocolitis). Selected topics in non-neoplastic paediatric gastrointestinal pathology are discussed. In this article, we briefly outline some specific gastrointestinal entities which may rarely be encountered in adult surgical pathology practice, including aspects of inflammation, infection, congenital abnormalities and those related to prematurity. Differences of certain pathologies between adults and children presenting with the same disease are highlighted.
Reflux oesophagitis Gastro-oesophageal reflux (GOR) describes backwards flow of gastric or, rarely in children, duodenal contents into the oesophagus. GOR disease (GORD) can present any time in childhood but is particularly common during infancy, due partly to an immature lower oesophageal sphincter. Frequent effortless regurgitation is very commonly noted but other non-specific symptoms leading to presentation include prolonged crying, irritability, vomiting and failure to thrive (FTT). Feeding refusal, poor growth, abdominal pain and chronic cough are more frequent in toddlers through to adolescents. Haematemesis is occasional. Presentation in adults is classically of heartburn, dysphagia and chest pain, which comprise less than 15% of presenting symptoms in older children.2 Infantile reflux usually resolves within two years, however, persistent reflux is not uncommon when presenting in older children. Risk of GORD is increased in children with neurological impairment, cystic fibrosis (CF), bronchopulmonary dysplasia and post oesophageal atresia (OA) or tracheo-oesophageal fistula (TOF) repair. Complications of chronic GOR include oesophageal stricture, mucosal ulceration, bleeding and Barrett’s metaplasia. Features on microscopy are similar to those seen in adults and are not specific but include basal hyperplasia (>15e20% of the mucosal depth), elongation of subepithelial papillae (much more than 50%), capillary congestion, basal layer spongiosis, acanthosis and balloon cells. Intraepithelial lymphocytes (IELs) and eosinophils may be present (latter more significant if >6 per high power field (HPF)). Features can be patchy. The gastric cardia can be inflamed in GORD. Clinical correlation and with pH studies is important as a large proportion of patients with GOR show normal histology.
Keywords congenital; duplication cyst; enterocolitis; eosinophils; gastritis; gastrointestinal; pediatric
Introduction The spectrum of gastrointestinal tract (GIT) disorders seen in paediatric patients is wide and the pathology differs partly from those seen in general adult pathology, with some overlapping areas. Pathologies related to congenital anomalies and immature development comprise a larger fraction than in adult surgical pathology. Neoplasms are uncommon. It is not possible to cover all aspects of paediatric gastrointestinal pathology in this article. The reader is thus referred to detailed review articles discussing paediatric gastrointestinal neoplasia, polyps, dysmotility disorders including Hirschsprung’s disease, and enteropathies of infancy including eosinophilic gastroenteritis, published in a specific paediatric GIT and liver mini symposium previously in this journal.1 This article is aimed at providing a brief overview of some of the other main gastrointestinal conditions encountered in paediatric surgical pathology and noting differences in those disorders also commonly seen in adult pathology. Endoscopic biopsy findings by site will be discussed first, followed by congenital anomalies and other lesions submitted as larger resection specimens.
Eosinophilic oesophagitis (EO) Two decades ago it was noticed that some children with refluxtype symptoms, who did not improve on anti-reflux treatments, showed very prominent mucosal eosinophilia. Atopic disorders were more prevalent within this subgroup; hence EO is also known as allergic oesophagitis. Caucasians, male gender and atopy are established risk factors (approximately 70% of patients or their family members have other atopic disorders3,4). pH studies are normal. In childhood, more EO patients present before 10 years of age. Similar symptoms as GORD occur, but a higher proportion of children also complain of “food getting stuck”. Endoscopic findings of linear furrowing/wrinkling or ‘trachealisation’ are more suggestive of EO. Microscopic features are
Denise Hiu-Jun Tao BSc (Hons) MSc MBBS, Histopathology Speciality Registrar, Southampton General Hospital, Southampton, UK. Conflicts of interest: none declared. Bhumita Vadgama MBChB FRCPath, Consultant Paediatric Pathologist, Southampton General Hospital, Southampton, UK. Conflicts of interest: none declared.
DIAGNOSTIC HISTOPATHOLOGY xxx:xxx
1
Ó 2019 Published by Elsevier Ltd.
Please cite this article as: Hiu-Jun Tao D, Vadgama B, Paediatric gastrointestinal pathology: selected topics, Diagnostic Histopathology, https:// doi.org/10.1016/j.mpdhp.2019.06.002
MINI-SYMPOSIUM: PAEDIATRIC PATHOLOGY
identified in children. Heavy neutrophilic inflammation is typical, often with a degree of ulceration and epithelial necrosis in HSV infection. Multinucleated giant cells are occasionally seen. Intranuclear HSV inclusions may be evident in the squamous epithelium around the ulcer edge, whereas CMV inclusions are usually located in stromal or endothelial cells at the base of ulcers. Candida pseudo-hyphae can be recognised in the epithelium and within fibrinopurulent exudate, which can be confirmed with Grocott or PAS stains. Rarely, other organisms may be suspected, e.g. Aspergillus, EpsteineBarr virus (EBV) and Varicella-Zoster virus.
similar to those seen in GORD but intraepithelial eosinophils are usually much higher (>20 per HPF). Although cut-off numbers are stated, generally speaking, clinically significant numbers tend to be obvious microscopically. Correlation with the pattern of infiltration, distribution (throughout the oesophageal length favours EO) and comparison with previous biopsies may be more helpful as disease can be patchy. Superficial layering of eosinophils, aggregation, degranulation and eosinophil-laden surface slough are features which favour EO (Figure 1). Lymphocytes may be slightly increased and activated mast cells seen, but neutrophils are not readily identified. Basal cell hyperplasia is often prominent and fibrosis of the lamina propria may be present. EO may be secondary to, or associated with, eosinophilic gastroenteritis or a peripheral eosinophilia.
Other Other causes of oesophagitis in children include Crohn’s disease (CD), ingestion of toxic or caustic substances (e.g. batteries) and drug-induced oesophagitis. The latter includes chemotherapy effects and impaction of tablets. Some dermatopathies can affect the oesophageal mucous membranes (e.g. Stevens-Johnson syndrome).
Barrett’s oesophagus (BO) BO is defined as columnar intestinal metaplasia replacing the native oesophageal squamous mucosa. BO is rare in children and is almost exclusively seen in those with long-standing GORD. Prevalence is reported between 0.3 and 4.8%.5 In some countries, diagnosis requires the presence of goblet cells on histology (e.g. as defined by the American Society of Gastroenterology); however, this is not mandatory in the UK, under guidelines published by the British Society of Gastroenterology.5,6 Several types of columnar lined mucosa have been described in BO, including intestinal, gastric fundal and gastric cardia types. The presence of native oesophageal structures on histology (e.g. submucosal ducts) may help confirm origin from the oesophagus in columnar mucosa. However, very few biopsies tend to demonstrate these. The exact site of biopsy has to be clarified with the gastroenterologist for a diagnosis of BO. Goblet cells have characteristic morphology but Alcian blue stain (at pH 2.5) may help by highlighting the acid mucin within them. Dysplasia in paediatric BO is exceedingly rare.
Stomach Gastritis is frequently seen in children but remains more common in adults. Atrophic gastritis and gastric malignancy, dysplasia or metaplastic conditions are diagnosed extremely rarely in the paediatric population. The diagnosis of mild gastritis can be subjective. Microscopy of a normal paediatric stomach biopsy demonstrates scanty dispersed chronic inflammatory cells. Lymphocyte aggregates should be small, very infrequent, and located mainly in the deeper mucosa. Eosinophils are sparse.7 Infectious gastritis Helicobacter pylori (HP) gastritis is common in adults and histopathology is well known. It remains the most common cause of gastritis in children where an aetiology is identifiable. HP causes acute and chronic active gastritis often with prominent germinal centres in lymphoid follicles. The latter are more frequently seen in children. Activity tends to concentrate around the neck of glands and a lymphocytic gastritis type picture may be seen. Chronic inflammation in biopsies can persist for up to several years after treatment, but acute changes tend to disappear by two months.7 Helicobacter heilmannii is prevalent in household pets and some farm animals and causes gastritis uncommonly in children. Inflammation is less intense compared to HP infection and the gastric antrum is involved in nearly all cases. The organism is longer and more spiralled in appearance. Other infectious aetiologies are less frequently seen in paediatric gastric biopsies. CMV, HSV, mycobacteria, and fungal infections may rarely be detected in biopsies from immunocompromised patients. Bacterial gastritis is scarcely biopsied. A third of patients with clinical hypertrophic gastropathy have associated CMV infection. As classic Menetrier disease is exceedingly rare in children, if enlarged gastric folds are noted at endoscopy, screening for CMV infection should be considered. Hypertrophic gastropathy is occasionally seen in eosinophilic gastritis, HP gastritis, and gastric lymphoma. Microscopy features of hypertrophic gastropathy include oedema, a mixed chronic inflammatory infiltrate, focal atrophy, foveolar
Infectious oesophagitis Infectious oesophagitis is uncommon except in debilitated or immunocompromised children. White plaques seen at endoscopy are suspicious for fungal infection and discrete ulcers may be visible in herpes simplex virus (HSV) infection. Candida, HSV and cytomegalovirus (CMV) are the most common organisms
Figure 1 Eosinophilic oesophagitis demonstrating degranulation and clustering of eosinophils towards the luminal surface (superficial layering).
DIAGNOSTIC HISTOPATHOLOGY xxx:xxx
2
Ó 2019 Published by Elsevier Ltd.
Please cite this article as: Hiu-Jun Tao D, Vadgama B, Paediatric gastrointestinal pathology: selected topics, Diagnostic Histopathology, https:// doi.org/10.1016/j.mpdhp.2019.06.002
MINI-SYMPOSIUM: PAEDIATRIC PATHOLOGY
hyperplasia and reduced numbers of parietal and chief cells.7 In neonates, marked antral foveolar hyperplasia has been described after the use of prostaglandins to maintain a patent ductus arteriosus.8
Caucasian populations. Nearly all patients are HLA-DQ2 or HLADQ8 positive. There is an approximate 75% concordance rate in identical twins. Diagnosis is primarily a clinicopathological process after biopsy examination. In the UK, duodenal biopsy is not necessary in the symptomatic patient if the serum IgA anti-tissue transglutaminase (tTG) level is >10x the upper reference limit, they are HLA-DQ2 or DQ8 haplotype positive, and the IgA antiendomysial antibodies (EMA) are raised.11 The characteristic histological features are well reported e.g. villous atrophy, excess intraepithelial lymphocytes (IELs), increased background chronic inflammation and crypt hyperplasia. Marsh scoring of severity of changes is used in some centres. Minor neutrophilic activity may be seen, especially in young children. When small bowel architecture and IELs are within normal limits, clustering of IELs at the villus tip and a ‘crescendo’ pattern upward along the villus sides may be early clues; however these findings are not diagnostic. Mimics of GSE in children include cow’s milk protein (CMP) allergy, which is one of the commonest food allergies in children and can present with gastric, small bowel or colonic symptoms. Similar changes may be seen with soya, egg and other food allergens. Post-enteritis enteropathy can present as malabsorption in a child after resolution of an acute episode of viral gastroenteritis. Autoimmune enteropathy can cause marked villous atrophy and inflammation as well. Crypt apoptotic activity is increased.1,7 See Table 1 for more histopathological differential diagnoses.
Drug effects Chemical/reactive gastropathy is less common in children but some similar aetiologies to adults exist, e.g. bile reflux and drugs, particularly NSAIDs in older children. Steroids, NSAIDs and oral iron can cause erosions, with regenerative epithelial change in adjoining mucosa. Chronic inflammation occurs particularly in the gastric body with proton pump inhibitor (PPI) therapy, more so than in the antrum. The parietal glands appear dilated and are lined by bumpy protuberant cells, resembling fundic gland polyps. Clear cell change is seen with prolonged use. Lymphocytic gastritis Lymphocytic gastritis describes an excess of gastric intraepithelial CD3þ CD8þ lymphocytes (>25 per 100 epithelial cells) on a background of chronic inflammation within the lamina propria. Association with coeliac disease is well known and a wide range in prevalence, up to 40%, is reported. It can be seen in CD, some cases of HP gastritis, and rarely autoimmune conditions. Granulomatous gastritis Non-necrotising granulomas in stomach biopsies of CD patients constitute the largest group with this morphology in children. Other systemic causes include mycobacterial or Histoplasma infection and, rarely, chronic granulomatous disease (CGD), granulomatosis with polyangiitis, sarcoidosis, common variable immunodeficiency (CVID) and Langerhans cell histiocytosis.
Infectious enterocolitis Acute bacterial (more commonly campylobacter jejuni, escherichia coli, shigella) and viral (e.g. rotavirus, Norwalk virus, astrovirus) infections are rarely biopsied and are diagnosed mainly on stool culture ELISA or PCR. Yersinia enterocolitica can mimic IBD or appendicitis by causing an inflammatory mass near the ileocaecal junction. Adenoviral infection can occur in the immunocompromised child10 and can cause a lead point for intussusception by eliciting marked lymphoid hyperplasia. CMV is not uncommonly seen and can mimic necrotising enterocolitis (NEC) by causing severe haemorrhagic colitis with scattered discrete ulcers. Microscopy features of giardiasis and cryptosporidium infection are summarised in Table 1.
Other In allergic/eosinophilic gastritis, eosinophils infiltrate the gastric mucosa especially within the antrum. This may be associated with hypersensitivity, food allergy, atopic disorders and autoimmune conditions. Serum IgE levels may be raised. It forms part of eosinophilic gastroenteritis.1,7 Gastric eosinophils may be increased also as part of chronic inflammatory bowel disease (IBD) and rarely can be associated with parasitic infection, drug reaction or connective tissue disorders. Gastric polyps are rare in the paediatric population although juvenile polyps and Peutz-Jeghers polyps do occur in the stomach.1 Fundic gland polyps may be seen in Familial Adenomatous Polyposis (FAP) and can resemble the changes associated with PPI use (see above). Further investigation for FAP may need to be considered by clinicians if there is a negative drug history for PPIs. Fundic gland polyps are usually very small, located in the body or fundus and show foveolar hyperplasia and dilated cystic glands but lack parietal cell hyperplasia.
Immunodeficiency (ID) ID of the GIT in children is a complex expanding group of disorders which can be classified into primary or secondary aetiologies. There are some overlapping features with autoimmune enteropathy; however a paucity of lamina propria plasma cells is the main suggestive feature of ID. Examples of primary diseases include selective IgA deficiency, CVID, X-linked agammaglobulinaemia and severe combined immunodeficiency (SCID). SCID presents in infancy and may be fatal without bone marrow transplant.10 IgA deficiency is the most common ID (incidence up to 2:1000) and is associated with other autoimmune processes e.g. pernicious anaemia and GSE. It is also increased in families with CVID. There are some histological similarities to GSE except for the lack of plasma cells. With IgA deficiency, screening for GSE should be carried out with IgG-linked antibodies instead of IgA-tTG. Chronic granulomatous disease (CGD) is due to NADPH oxidase pathway mutations leading to ineffectual ‘oxidative burst’ during phagocytosis, with 60% of cases showing X-linked
Small and large intestines Detailed descriptions regarding infantile enteropathies, eosinophilic gastroenteritis and Hirschsprung’s disease are available in standard paediatric pathology textbooks and review articles.1,5,7,9,10 Coeliac disease/gluten sensitive enteropathy (GSE) GSE, which is a T-cell related immune response, is the most common small bowel mucosal disorder causing malabsorption in
DIAGNOSTIC HISTOPATHOLOGY xxx:xxx
3
Ó 2019 Published by Elsevier Ltd.
Please cite this article as: Hiu-Jun Tao D, Vadgama B, Paediatric gastrointestinal pathology: selected topics, Diagnostic Histopathology, https:// doi.org/10.1016/j.mpdhp.2019.06.002
MINI-SYMPOSIUM: PAEDIATRIC PATHOLOGY
Mimics of coeliac disease in small bowel biopsies from children5,7,9,10 Villus architecture
Cow’s milk protein/other food allergy
Intraepithelial Lamina propria lymphocytes chronic inflammation
Patchy mild to moderate Mildly atrophy increased
Increases in Other features Neutrophils (PMNs)/ eosinophils (Eos) [ Eos, may be mild No [ PMNs
Patchy, mild
Non-IgE mediated Symptoms can be mild to severe, including PR bleeding, protein losing enteropathy, FTT, constipation. Post-enteritis Patchy variable atrophy Usually normal Patchy, mild to Not usually Clinical history of recent infection enteropathy moderate increased May last weeks to months after initial viral infection has resolved Crohn’s disease Possible villus blunting May be Variable, patchy. Patchy [ of both, Non-necrotising granulomata with possible glandular increased may see glandular architectural distortion abscesses. [ Eos more often in deep mucosa. Autoimmune Partial to total villous Minor if Variable, Sometimes [ of Seen in infants or young children more, with enteropathy atrophy with possible present predominantly both variable severity of pathology glandular destruction lymphocytes and Mimics GVHD Reduced goblet cells with plasma cells May have other autoimmunity e.g. DM type 1 increased Can be associated with IPEX syndrome cryptal apoptosis (Immunodysregulation, Polyendocrinopathy, Enteropathy; X-linked): with FOX3P mutations Giardia lamblia Commonly normal Occasional Mild if present Sometimes minor Biopsy may be entirely normal mild excess [of both Surface organisms resemble ‘falling leaves’ Cryptosporidium Variable mild to Not typical Mild, may be mixed Mixed History of note: occasionally severe acute and chronic Inflammation with Immunocompromised patients, travel history, atrophy inflammatory cells occasional exposure to farm animals cryptitis Stool examination for parasites Organisms resemble ‘blue beads’ on surface epithelium on microscopy CVID Variable atrophy Possible Nodular lymphoid Sometimes acute Low serum levels of IgA, IgM and IgG hyperplasia with inflammation with Can mimic autoimmune enteropathy plasma cell paucity [ of both Occasionally granulomata seen Table 1
inheritance. CGD patients are prone to infection by catalasepositive organisms, e.g. candida and staphyloccocus aureus. Histological features mimic IBD and can show patchy inflammation anywhere in the GIT, including the mouth. Granulomas may be seen and the presence of light orange-brown pigmented macrophages is highly suggestive (Figure 2). Chronic mucocutaneous candidiasis is a T-cell related disorder presenting in infancy, and which can lead to polyendocrinopathy.7,9 Graft versus host disease (GVHD) occurs more commonly after bone marrow or stem cell transplant, affecting the GIT in nearly half of acute presentations.10 Acute GVHD typically shows increased epithelial apoptotic debris deep within the crypts. There may be villous atrophy and features may partly resemble autoimmune enteropathy. Eosinophils can be seen. However, changes may be patchy so multiple biopsies are advised. As mycophenolate induced injury can show similar features, clinical correlation is essential (Figure 3).
DIAGNOSTIC HISTOPATHOLOGY xxx:xxx
Colitis Chronic IBD constitutes a large proportion of the workload (diagnostic/disease surveillance biopsies and resections) in paediatric GIT pathology. The main clinical and pathological features, both on macroscopic inspection and on microscopy, greatly mirror those seen in adults and will not be discussed. Hence only specific differing points will be mentioned. Nearly one-fifth of IBD patients are diagnosed before 15 years of age and the diagnosis of CD has slowly risen over 40 years. Clinical presentation is mostly similar to adults (e.g. diarrhoea, abdominal pain) but children can present with FTT or delayed onset of puberty. In children, both ulcerative colitis (UC) and CD are most commonly diagnosed in adolescence, however in UC, 3% are aged 5 years or less.5,7,9 In UC, children more often present with extensive colonic disease than adults. Backwash ileitis and pancolitis is seen more frequently in children and can be more extensive. Patients with UC may present with a caecal patch and skip lesions in the
4
Ó 2019 Published by Elsevier Ltd.
Please cite this article as: Hiu-Jun Tao D, Vadgama B, Paediatric gastrointestinal pathology: selected topics, Diagnostic Histopathology, https:// doi.org/10.1016/j.mpdhp.2019.06.002
MINI-SYMPOSIUM: PAEDIATRIC PATHOLOGY
may even lead to reversal of early chronic features. In severe ulcerating disease, extension into the submucosa may occur in UC. Upper GIT involvement in UC is also more frequent in children than adults, commonly chronic gastritis, but minor activity may also be seen. CD in children presents with pancolitis in nearly half of cases (adults about 20%) but stricturing or fissuring disease is less common. Around 40% present with ileal disease alone. Granulomas are identified more often in paediatric biopsies than in adult cases.5
Congenital surgical disorders and abnormalities of the gastrointestinal tract There are numerous congenital surgical disorders and abnormalities of the GIT which cannot all be covered in this article. We present a few (other than congenital dysmotility disorders) that can result in a surgical specimen. Oesophageal resections are uncommon and occasional specimens from acquired oesophageal stenoses (e.g. sequelae of caustic or thermal injury) may be submitted, showing submucosal fibrosis and possible non-specific chronic inflammation.
Figure 2 Chronic granulomatous disease can mimic Crohn’s disease. Patchy inflammation, abscesses and granulomas may be seen. Light orange-tan finely pigmented macrophages (seen here) are typically identified in the deeper lamina, more often in the less inflamed areas.
appendix. Focal active colitis only may be noted in rectal biopsies more often in children with UC at first presentation. As chronic features are absent in these rectal biopsies with focal activity, the term “relative rectal sparing” is applied. Relative rectal sparing can be seen initially in just less than a quarter of children who go on to be diagnosed with UC and thus focal active colitis is more ominous toward IBD in children than in adults.5,12 Treatment
Tracheo-oesophageal fistula (TOF) and oesophageal atresia (OA) TOF is an anomalous fistulous connection between the proximal and/or distal oesophagus and the tracheobronchial tree. OA and TOF most often occur together, in around 1 in 3000 births, resulting from variable incomplete division of the primitive foregut in the fourth and fifth weeks of gestation. There may be associated maternal polyhydramnios. OA without TOF is suggested on prenatal ultrasound screening by a small stomach with no gas bubble. An accompanying TOF can diminish these features. TOF/OA are classified into five main types dependent on the presence of OA only (more common in trisomy 21); OA with variably connected TOF; and TOF only. By far the most prevalent (85%) is of an upper oesophageal pouch, with a distal TOF, entering close to the carina, thus leaving a relatively short gap, more amenable to repair. Neonates require emergency surgery as choking, respiratory distress, or aspiration can ensue. The tracheal or bronchial fragments often show squamous metaplasia but the oesophageal pouch (more commonly submitted) may show abnormal mucous glands, disorganised muscular layers or cartilage.10,13 Approximately one half of infants with OA/TOF have associated congenital anomalies, frequently of midline structures. Cardiac abnormalities are found in about 30%. GIT anomalies (e.g. duodenal atresia or diaphragmatic hernia) are seen in 20% and approximately 25% of infants demonstrate VACTERL association syndrome (vertebral, anorectal malformation, cardiac, tracheo-oesophageal fistula, renal anomaly and limb defects). 6 e10% have associated chromosomal abnormalities such as trisomy 13, 18, or 21.13,14 Long-standing GOR is a common complication in many, with higher risk of BO. Duplication cysts Oesophageal duplication cyst is rare but more often lies adjacent to the lower half of the thoracic oesophagus. It may be separate or share part of the main oesophageal wall. The layers of the
Figure 3 In GVHD crypt apoptotic activity is prominent with variable cryptal debris and inflammation (as seen here). Crypt dropout may be seen. Severe cases show ulceration and surface denudation. Regenerative changes may occur later. Organisms of opportunistic infections should be bourne in mind.
DIAGNOSTIC HISTOPATHOLOGY xxx:xxx
5
Ó 2019 Published by Elsevier Ltd.
Please cite this article as: Hiu-Jun Tao D, Vadgama B, Paediatric gastrointestinal pathology: selected topics, Diagnostic Histopathology, https:// doi.org/10.1016/j.mpdhp.2019.06.002
MINI-SYMPOSIUM: PAEDIATRIC PATHOLOGY
wall of a duplication cyst are mainly normal and the lining mucosa may be stratified squamous or columnar, with or without cilia. A bronchogenic cyst is a differential diagnosis in the thorax. If ciliated epithelium is present, the differential may be difficult. Bronchogenic cysts tend to lack an organised muscularis propria, and cartilage or respiratory glands can be present. Occasionally, a gastroenteric cyst may add to the confusion in the mediastinum. They usually occur in the right posterior mediastinum. Some extend into the spinal canal (termed neuroenteric cysts). The spectrum of these neuroenteric remnants (split notochord syndrome) encompass gastrointestinal diverticula, fistulae, cysts, dorsal dermoid cysts or sinuses and cords. They extend from the dorsal midline GIT, upward and, possibly to the spinal cord or posterior skin, undergoing segmental obliteration along its path. Neuroenteric cyst linings show potentially any gastrointestinal epithelia (site dependent) and may include neuroglial or meningeal tissues.7 Gastric duplications lie more frequently along the greater curvature. Duplication cysts are most common in the small intestine area. Similar well-organised transmural features are noted with varying gastric, intestinal to simple epithelial linings evident (Figure 4).
Malrotation results from an aberration at any point during the return and fixation of the externally rotated GIT back into the body cavity (gestational weeks 10e11). Malrotation and Meckel’s diverticulum are risk factors for volvulus and intussusception. Malrotation is frequently associated with other abnormalities, e.g. ileal atresia and Hirschsprung’s disease. Intestinal atresia and stenosis Atresia is when the lumen is interrupted. Atresias of the colon and stomach are rare; hypertrophic pyloric stenosis is the main form of congenital stenosis seen in the stomach. The most common sites of atresia affect the duodenum, proximal jejunum and distal ileum. The former is seldom sent as a surgical specimen. Multiple small bowel atresias occur in 10% of patients. Jejuno-ileal atresias have been classified into 5 types, ranging from just membranous atresia (type I) where the bowel wall and mesentery are intact, to multiple intermittent atresias along a length of bowel (type IV). The most common form is type III (two blind ends are present without an intervening fibrous cord). Atresias are mainly considered to be due to intrauterine vascular events leading to ischaemia, infarction, absorption or fibrosis. Histology reveals fibrosis and calcification obliterating the lumen, mucosa and submucosa but a residual muscularis propria is often recognisable. There may be luminal granulation tissue. Features suggestive of CF should be sought (see below). Anorectal malformations can be complex. Small fragments from the surgical repair are often received, showing skin, anorectal mucosa, urothelium to vaginal squamous mucosa.
Exomphalos and vitellointestinal maldevelopment Exomphalos (omphalocoele) occurs when the midline developmental anterior abdominal wall defect fails to close. Viscera may remain bulging into the sac if normal physiological return into the abdominal cavity is disturbed. The sac may be excised and comprises amnion, parietal peritoneum, and connectives tissues. The umbilicus inserts into the dome of the sac. Faulty obliteration of all or part of the vitellointestinal (omphalomesenteric) duct during embryonic GIT development can result in a fistula with the ileum, Meckel’s diverticulum, and fibrous cords or distally as omphalomesenteric cysts, fistulae or umbilical granulomas. Remnants can show various types of GIT mucosa or even pancreatic heterotopia. Meckel’s diverticulum is a frequently submitted specimen; occurring in 2% of the population and constituting 90% of all omphalomesenteric duct related abnormalities. Presence of gastric and pancreatic heterotopia with potential ulcerative sequelae is well known.7,9
Figure 4 Duplication cyst with normal native bowel wall (upper right). The duplication cyst (lower right) shows its own well-organised wall (including both layers of the muscularis propria), merging with the native bowel wall (left). In this case the cyst is lined by markedly attenuated flattened epithelium.
DIAGNOSTIC HISTOPATHOLOGY xxx:xxx
Figure 5 Ileum of neonate showing early mucosal haemorrhagic necrosis. Note the deep crypt lumina expanded by densely eosinophilic thick secretions. This is suggestive of cystic fibrosis.
6
Ó 2019 Published by Elsevier Ltd.
Please cite this article as: Hiu-Jun Tao D, Vadgama B, Paediatric gastrointestinal pathology: selected topics, Diagnostic Histopathology, https:// doi.org/10.1016/j.mpdhp.2019.06.002
MINI-SYMPOSIUM: PAEDIATRIC PATHOLOGY
Single juvenile polyps (not part of juvenile polyposis syndrome) are commonly rectal in site, cause PR bleeding in young children and comprise granulation tissue, dilated glands and lamina propria inflammation.
Disorganised muscle bundles and stroma with non-specific inflammation may be seen. Necrotising enterocolitis (NEC) NEC is the most common reason for emergency surgery in the newborn, primarily affecting premature infants. The exact aetiology remains unclear but translocation of microorganisms, cytokine activation and immature immunity of the bowel are just some of the multiple factors thought to contribute to its pathogenesis. The main risk factors are prematurity, bacterial colonisation and formula feeding. Recently it has been identified that the premature intestinal epithelium is predisposed to mounting an exaggerated inflammatory response to colonizing bacteria, leading to mucosal destruction (e.g. by increased enterocyte apoptosis) and impaired mesenteric perfusion. This heightened response is partly due to the already increased innate TLR4 (tolllike receptor 4) expression on the premature infants’ enterocytes. Gram negative bacteria can further activate TLR4, perpetuating the reaction. Reviews suggest that potential inhibitors blocking TLR4 may help in the future together with modifying other identified growth factors.15 Vitamin D is a regulator of TLR4. No specific treatment for NEC exists. When resection becomes necessary, potential long term sequelae are severe and include short gut syndrome, strictures and malabsorption. Small bowel NEC is seen more frequently than of the colon. On macroscopy, the bowel wall can show thinning, mucosal congestion and discolouration or perforation. NEC is characterised by coagulative and haemorrhagic mucosa and varying mural necrosis. It may be patchy in distribution or of confluent extent. Bacteria may be seen on the mucosal surface and scattered gas-filled cystic spaces may be present in the wall (pneumatosis intestinalis). The presence of ganglion cells should be confirmed, as in term infants, NEC may be a presentation of Hirschsprung’s disease.
Practice points C
C
C
C
C
C
C
C
Meconium ileus and peritonitis Meconium ileus is obstruction due to luminal impacted meconium debris, more common in the ileum or proximal colon of low birth weight infants. It is associated with CF in a significant proportion. 10e15% of babies with CF will have neonatal meconium ileus. Ileus is usually treated medically but a thick green luminal plug may be noted at resection and, on microscopy, dense eosinophilic material filling crypts is suspicious of CF (Figure 5). Exclusion of Hirschsprung’s disease is needed as it is a clinical mimic for ileus. If intra-uterine intestinal perforation occurs, the released meconium elicits a severe peritoneal reaction with inflammation, fibrosis, calcification and sometimes a foreign body type reaction. If the inguinal canal is still patent at the time of intra-uterine perforation, meconium periorchitis may also develop.
C
A REFERENCES 1 Mini-symposium: paediatric gastrointestinal and liver pathology. In: Bateman A, Mead Z, eds. Diagn Histopathology 2015; 21: 217e60. 2 Treem WR, Davis PM, Hyams JS. Gastroesophageal reflux in the older child: presentation, response to treatment and long-term follow-up. Clin Pediatr 1991; 30: 435e40. 3 Philpott H, Nandurkar S, Royce SG, Thien F, Gibson PR. Risk factors for eosinophilic esophagitis. Clin Exp Allergy 2014; 44: 1012e9. 4 Straumann A, Aceves SS, Blanchard C, et al. Pediatric and adult eosinophilic esophagitis: similarities and differences. Allergy 2012; 67: 477e90.
Other Intussusception and volvulus show features of haemorrhagic necrosis. The former occurs mainly near the ileocaecal junction and is seen more often in infants. Mass lesions should be excluded in the older child. Lead points can include pancreatic heterotopic nodules, polyps, small duplications or mucosal lymphoid hyperplasia (consider adenovirus). Rarely, GIT lymphoma may be seen.
DIAGNOSTIC HISTOPATHOLOGY xxx:xxx
EO can be a patchy disease. Ideally examine multiple multi-site biopsies along the oesophagus. Do not rely on eosinophil numbers alone. Examine the overall pattern and distribution of infiltrate in individual biopsies Mild basal hyperplasia and elongation of subepithelial papillae can be seen in biopsies close to the squamocolumnar junction in patients, even without GORD10 Persistent embryonic surface columnar epithelium, at either end of the oesophagus, may be seen especially in premature babies but should disappear by early infancy e this is different to inlet patch of heterotopic gastric mucosa in upper oesophagus At the gastro-oesophageal junction and gastric cardia of neonates and young children, acid mucins can occur within the columnar epithelium without goblet cells e beware of over-diagnosis of BO16 Prominent Brunner’s glands in D1 biopsies can distort architecture and cause mild villous blunting e this is not true atrophy Always consider the differential diagnosis of CGD in GIT biopsies for IBD from young boys with granulomatous inflammation e look for faintly pigmented macrophages in deep lamina propria, see Figure 2 Compared to adults, children with only focal active colitis in their initial GIT biopsies are much more likely to be diagnosed with IBD at a later stage e although not diagnostic, do not dismiss this finding; communicate with the clinicians In children, chronic and chronic active inflammation in the upper GIT is seen much more frequently in CD and even UC, compared to adult populations. Therefore, with upper GI inflammation alone, in the absence of granulomas CD should not be definitively diagnosed Be aware of dual pathologies (e.g. Giardia in a biopsy with features of CVID or other ID); or of masking pathologies (e.g. NEClike features in neonatal CF, see Figure 5)
7
Ó 2019 Published by Elsevier Ltd.
Please cite this article as: Hiu-Jun Tao D, Vadgama B, Paediatric gastrointestinal pathology: selected topics, Diagnostic Histopathology, https:// doi.org/10.1016/j.mpdhp.2019.06.002
MINI-SYMPOSIUM: PAEDIATRIC PATHOLOGY
IR, et al. European soci11 Husby S, Koletzko S, KorponayeSzabo ety for pediatric Gastroenterology, hepatology, and nutrition guidelines for the diagnosis of coeliac disease. J Pediatr Gastroenterol Nutr 2012; 54: 136e60. 12 Scudiere JR, Maitra A, Montgomery EA. Selected topics in the evaluation of pediatric gastrointestinal mucosal biopsies. Adv Anat Pathol 2009; 16: 154e60. 13 Polydorides AD. Alimentary canal. In: Putman AR, Thompson KS, eds. Diagnostic pathology: nonneoplastic pediatrics. Amirsys, 2013. 8.4-8.12. 14 Shaw-Smith C. Oesophageal atresia, tracheo-oesophageal fistula, and the VACTERL association: review of genetics and epidemiology. J Med Genet 2006; 43: 545e54. ~o DF, Sodhi CP, Hackam DJ. Necrotizing enterocolitis: new 15 Nin insights into pathogenesis and mechanisms. Nat Rev Gastroenterol Hepatol 2016; 13: 590e600. 16 Ellison E, Hassall E, Dimmick JE. Mucin histochemistry of the developing gastroesophageal junction. Pediatr Pathol Lab Med 1996; 16: 195e206.
5 Brundler M-A, Borralho P, Karikoski R, Domizio P, Cohen MC. Gastrointestinal tract. In: Cohen MC, Scheimberg I, eds. Essentials of surgical pediatric pathology. Cambridge University Press, 2014; 210e50. 6 Fitzgerald RC, Di Pietro M, Ragunath K, et al. British Society of Gastroenterology guidelines on the diagnosis and management of Barrett’s oesophagus. Gut 2014; 63: 7e42. 7 Russo P, Ruchelli ED, Piccoli DA, eds. Pathology of pediatric gastrointestinal and liver disease. New York: Springer-Verlag, 2004. 26-27 and 47-87. 8 Peled N, Dagan O, Babyn P, et al. Gastric-outlet obstruction induced by prostaglandin therapy in neonates. N Engl J Med 1992; 327: 505e10. 9 Gastrointestinal pathology. In: Sebire NJ, Malone M, Ashworth M, Jacques TS, eds. Diagnostic pediatric surgical pathology. Churchill Livingstone Elsevier, 2009; 529e600. 10 Hart J, Wilcox R, Weber CR. The gastrointestinal tract. In: Stocker JT, Dehner LP, Husain AN, eds. Stocker and Dehner’s paediatric pathology. Philadelphia: Lippincott Williams & Wilkins, 2011; 586e627.
DIAGNOSTIC HISTOPATHOLOGY xxx:xxx
8
Ó 2019 Published by Elsevier Ltd.
Please cite this article as: Hiu-Jun Tao D, Vadgama B, Paediatric gastrointestinal pathology: selected topics, Diagnostic Histopathology, https:// doi.org/10.1016/j.mpdhp.2019.06.002