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Diagnosis and treatment of foregut duplications
Diagnosis and Treatment of Foregut Duplications By Georges Azzie and Spencer Beasley Christchurch, New Zealand In its broadest sense, the term, foregut duplication encompasses the full spectrum of developmental aberrations of the embryonic foregut (bronchopulmonary and alimentary tract). Evidence is emerging that the notochord may have a pivotal role to play in foregut development through the Shh-GLi signalling pathway. The investigation and management of these lesions depends on the clinical presentation and the level of the foregut affected. The presentation of symptomatic foregut duplications also depends on any space-occupying effect they exert and where specific complications related to the malformation occur, such as when the mucosal lining contains acid-secreting cells. In a minority of cases, (eg, where they cause respiratory compromise or spinal cord compression) urgent intervention is required. In the remainder, precise diagnostic imaging according to the level and Iocation of the foregut duplication provides the necessary information to plan surgical excision of the lesions. Magnetic resonance imaging best shows the relationships of complex bronchopulmonary foregut malformations and associated anomalies of the spine, eg, neurenteric canal. Most lesions can be excised with minimal morbidity. Minimal-access surgical techniques can be applied to the simpler cysts, particularly some bronchogenic cysts. Thoraco-abdominal duplications and neurenteric cysts require careful preoperative delineation and more complex surgery.
Copyright 2003, Elsevier Science (USA). All rights reserved.
HE PRIMITIVE FOREGUT gives rise to the pharynx and its derivatives, the respiratory tract (trachea and lungs), esophagus, stomach, and duodenum to the level of the ampulla of Vater. No single embryologic theory explains the spectrum of anomalies covered by the heading "foregut duplications." The split notochord theory 1,2 is an attractive explanation for some alimentary tract and spinal anomalies, eg, neurenteric canal, but does not explain the full spectrum of lesions observed. The notochord appears to have a pivotal role to play in foregut development34 as the organizer of paraxial organogenesis. There is some evidence emerging that altered expression of the sonic hedgehog gene by the notochord affects the Shh-GLi signalling pathway and may contribute to a spectrum of bronchopulmonary, alimentary tract and associated anomalies (including esophageal atresia, pulmonary sequestrations, and cervical hemivertebrae)Y Bronchopulmonary foregut malformations have
T
been observed in the Adriamycin-induced rat model of the VATER association. 9J° The exact embryogenesis of foregut duplications remains to be determined. THE SPECTRUM OF FOREGUT DUPLICATIONS
In 1968, Gerle et al u proposed that the term bronchopulmonary foregut malformations be used to encompass the full spectrum of developmental aberrations of the embryonic foregut. The termforegut cyst 12is used today to describe a spectrum of bronchopulmonary malformations, typically bronchogenic cysts and combined pulmonary sequestrations associated with mixed bronchogenic and esophageal duplications 13 as well as the more traditional duplications of the alimentary tract from the pharynx to the duodenum. The classical features of alimentary tract duplications are that they have (1) a welldeveloped coat of smooth muscle, (2) an epithelial lining representing some portion of the alimentary tract (unless destroyed by infection), and (3) an intimate attachment to some portion of the foregut. The classical definition of foregut duplications has difficulty accommodating all variations, such as esophageal duplications that lie adjacent to or distant from the esophagus without sharing a muscular wall with it, TM or bronchogenic cysts containing cartilage that are attached to the wall of the lower esophagus, far away fi'om any bronchus. Typically, the mucosal lining of a foregut duplication is that of the respiratory or alimentary tract, but it can vary anywhere from ectopic respiratory pseudostratified ciliated columnar epithelium to ectopic gastric foveolar epithelium with fundic or pyloric glands. All may coexist in a single malformation. 1>19 Proof of the hybrid nature of some of these lesions is that gastric duplications can be lined with pseudostratified ciliated columnar (respiratory) epithelium, 16 and esophagogastric lesions can be lined with smooth muscle and cartilage as well as tissue resembling disorganized bronchioles with combined ciliated and squamous epithelium. 2° CLINICAL PRESENTATION
From the Department of Paediatric Surgery, Christchurch Hospital, Christchurch, New Zealand. Address reprint requests to Professor Spencer Beasley, MS, FRACS, Department of Paediatric Surgery, Christchurch Hospital, Private Bag 4710, Christchurch, New Zealand. Copyright 2003, Elsevier Science (USA). All rights reserved. 1055-8586/03/1201-0006535.00/0 dei: 1O.1053/spsu.2003.50000 46
The mode of presentation of symptomatic foregut duplications depends on 3 factors: (1) the anatomic level of the foregut involved, (2) the mass effect of the lesion, and (3) specific complications related to the malformation (usually associated with its mucosal lining containing acid secreting cells). Seminars in Pediatric Surgery, Vol 12, No 1 (February), 2003: pp 46-54
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Intrathoracic Duplications
Pancreatic Duplications
Most foregut duplications are located in the thorax. Nonspecific symptoms of pain or discomfort often are secondary to their space-occupying effect mainly because enlargement occurs in a relatively confined space (as with bronchogenic cysts and esophageal duplications in the posterior mediastinum). As the lesion enlarges further, symptoms related to compression of adjacent structures may become more specific and include cough, wheezing, dyspnea, hemoptysis, recurrent infections (caused by airway compression), and dysphagia (caused by esophageal compression). Gastric mucosa lining a foregut duplication is well known to cause symptoms: it occurs in about one third of esophageal duplications. 14 Although it may be an incidental finding in some cases, gastric mucosa also may lead to ulceration and bleeding within the cyst 14 or produce a peptic esophageal stricture. 21 Many foregut duplications are identified on routine imaging in an asymptomatic patient or even prenatally by ultrasonography. This is especially true of bronchogenic cysts, esophageal duplications, and extralobar pulmonary sequestrations, which present frequently as incidental findings on routine chest x-ray.
The mass effect of a duplication in the head of the pancreas may cause abdominal pain and features of pancreatitis. 2°,26-28 Ectopic gastric mucosa in foregut duplication cysts involving the pancreatic head in 2 patients has been found to produce increased levels of gastrin and gastritis. 27
Gastric Duplications Gastric duplications are rare, accounting for about 5% of abdominal duplications. 22 The typical presentation is of vomiting from gastric outlet obstruction and a palpable epigastric mass. An upper abdominal mass is palpable in up to 50% of cases. 21 Although vomiting is the most common presentation of gastric duplications, hematemesis and melena are not uncommon. ~4,2I Persistent vomiting may mimic pyloric stenosis and is caused by gastric outlet compression. 23-25Some gastric duplications are completely separate from the stomach within the retroperitoneum. Most do not communicate with the lumen of the stomach. Weight loss may be secondary to dehydration and malnutrition from protracted vomiting. Peptic ulceration may cause pain. Bleeding and perforation are the most common complications of gastric duplications and may be the only symptoms at first presentation. About a third are diagnosed in the neonatal period; the rest present throughout childhood.
Duodenal Duplications Duodenal duplications are rare and difficult to diagnose. Most patients have a long history of vague and nonspecific symptoms or intermittent obstruction. Most duodenal duplications are cystic, but a few communicate with the duodenum. Some present with jaundice from extrinsic compression of the common bile duct.
DIAGNOSTIC IMAGING
Intrathoracic Lesions Foregut duplications in the chest are best investigated initially with a chest x-ray. Posterior-anterior and lateral views are able to detect lesions in over 90% of cases (Fig lA). 29 Vertebral anomalies, if present, increase the chances that a lesion seen on chest x-ray is a foregut duplication and that there may be associated spinal anomalies (neurenteric canal). 3°-33 In one series 12 of 58 patients with bronchopulmonary foregut malformations (either bronchogenic cysts or esophageal duplications) 47 had abnormal chest radiograph findings: 86% of these consisted of either a posterior mediastinal mass or a parenchymal lung lesion, whereas the remainder were related to the space-occupying mass effect of the cyst or to a secondary pneumonic (infective) process. Others have reported similar findings. 34 Thoracic ultrasonography, especially in younger children, may identify some small anterior and central opacities undetected on standard chest x - r a y s . 29,35,36 However, ultrasonography is of limited value in the detection of most posterior mediastinal lesions 29 and is not performed routinely. Antenatal ultrasonography has been successful in the detection of intrathoracic foregut duplication cysts in 2 fetuses with hydrops. 37 This modality also has detected a thoraco-abdominal duplication cyst as an incidental finding on routine antenatal examination, allowing early postdelivery management. 38 Contrast studies (eg, barium swallow) may show a mass effect, as shown by compression of the esophagus or displacement from normal alignment, and may be used to determine whether there is any communication with the esophagus, although this is rare. 39-41 A computed tomography (CT) scan enables evaluation of mediastinal organs in a transverse plane and helps establish the borders of the lesion and its relationship to normal structures (Fig 1B). 42'43 The CT also has a role in screening cases in which the chest x-ray has been uncertain or equivocal. The scan evaluates the density of the lesion and, with IV contrast, shows whether the lesion perfuses, ie, provides information about its vascularity. The spiral CT provides the best definition of relationships of the bronchial tree and gives 3-dimensional reconstructions of mediastinal masses? 9
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AZZIE AND BEASLEY
Fig 1. (A) Posterior-anterior chest x-ray of a 5-year-old girl shows a well-defined circular opacity in the left hemithorax posteriorly, partly obscured by the left hemidiaphragm and left heart border. (B) Transverse section on CT of the Iower chest shows the same lesion as in Fig l A at the left lung base, There are no obvious abnormal vessels supplying it. (C) MRI scan (TzW) of the chest, coronal plane, shows an oval cystic lesion at the left base posteriorly and medially, There is no evidence of a connection with the esophagus or spinal canal, and no associated vessels can be seen (same patient as l A and 1B).
Magnetic resonance imaging (MRI) is valuable in the diagnosis of intrathoracic lesions in children because it helps avoid exposure to ionizing radiation, and its sagittal and coronal scans provide accurate information about the vascular anatomy without the need for IV contrast (Fig lC). 13'29 For example, it may show the aberrant vessel supplying a pulmonary sequestration. It is particularly useful for detecting associated anomalies of the spine, such as neurenteric canal. MRI has largely replaced myelograms and CT myelography in the diagnostic imaging of neurenteric forms of foregut anomalies. It defines the relationship to surrounding structures precisely and detects anomalies of the spinal column and the spinal cord. 44 Drawbacks in its use are that children frequently require general anaesthesia or sedation for the procedure, and it is unsuitable for examination of the bronchial tree. Where the bronchopulmonary foregut malformation is complex, MRI best shows the relationship between different components of the mass. 13
In the adult literature, endoscopic ultrasonography has been used to diagnose mediastinal cysts and to determine whether an esophageal impression is intramural or extrinsic to the esophageal wall. 41,45,46 There is little experience using this technique in children.
Intraabdominal Lesions The imaging of foregut duplications below the diaphragm is particularly amenable to ultrasonography. Screening for the intraabdominal extension or separate intestinal duplication that may accompany intrathoracic duplication cysts 14,47-49 is best done with abdominal ultrasonography. 5°43 This association was reported in 30% of the thoracic duplications in one series, but is uncommon in other reports. Duplications are identified by their gut signature, a term that is used to describe the hyperechoic inner layer that is produced by the mucosa and the relatively hypoechoic outer layer produced by smooth muscle. 5°-53 Peristaltic activity within the structure of the
FOREGUT DUPLICATIONS
cyst also may be visible. »4 Further investigation using other imaging modalities may better define the location, size, and precise anatomic relationships of the lesion to surrounding structures. Endoscopic ultrasonography has been shown to be accurate but invasive. 19 Contrast studies can show communication between the duplication and the intestinal tract as well as shed light on complex anatomic relationships. 65 A CT scan is an alternative modality to identify the precise location and size of the lesion and give information about its effects on surrounding structures, such as edema of the pancreas with duplication of the pancreatic head.51,53 MRI offers little in the way of further information unless characterization of the biliary-pancreatic system is required. In this case, MR cholangiography is a noninvasive way to detect abnormalities »6,57 and may give results comparable with those of endoscopic retrograde cholangiopancreatography (ERCP)? 7 However, the latter remains the gold standard to outline choledochal and pancreatic ductal anatomy and show any communication between the duplication cyst and the main pancreatic duct. 58,»9 Intraoperative ultrasonography may assist in the localization of cysts not easily visible in the pancreas, and intraoperative pancreatography may be useful to outline adjacent ductal relationships. Nuclear medicine studies (technetium 99 scanning) have been used to diagnose gastric duplications, but there are limitations to this technique because of the normal gastric uptake of isotope. 23 The sensitivity of detecting ectopic gastric mucosa with 99m Tc pertechnetate approaches 85% and is best when the patient is pretreated with cimetidine or glucagon. 6° A disosopropyl-acetanilide iminodiacetic acid (DISIDA) scan may help distinguish a duodenal duplication from a choledochal cyst. 22 Variation in the radiologic expertise and technical equipment available may affect the diagnostic algorithm that is used from center to center. RATIONALE FOR SURGICAL EXCISION
In general, foregut duplications should be excised. In incidentally diagnosed foregut duplications, particularly bronchogenic cysts, their usually benign course has encouraged some to advocate less invasive treatment such as needle aspiration and injection of a sclerosing agent, 27,61 but there are no good long-term follow-up data available. Orte large adult study has found that 82% of foregut duplication cysts were either symptomatic, complicated, or both at the time of surgery, and that they were associated with a high rate of intraoperative complications (14%), including division of the vagus nerve
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and injuries to the esophagus and bronchus. 62 This led the investigators to recommend early resection when these lesions are first identified. In children, expectant management of asymptomatic lesions is not considered appropriate because most eventually will have symptoms or complications. The nature of the complication varies according to the level of the foregut affected: features include feeding difficulties with floor of mouth lesions, 63 airway-related problems, 64,65 dysphagia, 21 and vomiting mimicking pyloric stenosis. 24,66,25Thoracic lesions are of concern because they occupy space otherwise destined for growing respiratory tissue. 64 Pneumonia is a common sequela to bronchogenic duplications. 65 Foregut duplications within the pancreas can cause pancreatitis by virtue of their mass effect. 2628 Complications unrelated to the mass effect of the duplication include (1) bleeding (related to ectopic gastric mucosa) either within the duplication itself or in adjacent alimentary tract, 14'21'67 (2) perforation of the duplication, 67 (3) peptic esophageal stricture, 2J and (4) malignant transformation. 64,68-7°There is general consensus thät foregut duplications are best excised becanse of their propensity to produce complications. SURGICAL TREATMENT
The most practical approach to the treatment of foregut duplications is one based on the anatomic level at which it is predominantly located.
Thoracic Duplications The main issues surrounding the surgical approach to intrathoracic foregut duplications relate to whether the lesions are best removed via an open thoracotomy or with video-assisted thoracoscopic surgery. The other concern is that some have a concomitant, intraabdominal component] 4,47-49 Any intraabdominal extension is best identified pre-operatively because this may affect the choice of surgical approach. Bronchogenic cysts. Traditionally, bronchogenic cysts have been resected via open thoracotomy, usually by a posterolateral intercostal approach. The procedure normally is straightforward unless the cyst has been infected and is surrounded by inflammatory changes. In recent years, minimal access surgical techniques have been applied to these lesions in both adults vl,72 and children. 6» Descriptions of minimal access surgical techniques have highlighted the importance of complete resection (to reduce the risk of recurrence) and identified an incidence of post resection pneumothorax associated with centrally located bronchogenic cysts. Merry et a165 described persistent air leak in 2 of 8 children; although this is a small series, it does constitute the largest experience reported
50
Fig 2. Operative appearance of a tubular duplication of the esophagus: it shared part of its wall with the normal esophagus.
of foregut-derived duplications resected by minimal access surgery. The investigators have suggested that central mediastinal lesions require chest robe drainage postoperatively.65 Esophageal duplications. Open right thoracotomy and resection has been the standard treatment for esophageal duplications (Fig 2). In the largest published series, 20 of 2 1 patients underwent successful primary resection of the duplications that were dissected free from surrounding structures. 14 Complete excision with segmental esophageal resection may be required when the shared esophageal wall of the cyst is too intimate to allow excision of the duplication alone. 21 Alternatively, marsupilization with stripping of the mucosa of the cyst at its common wall with the esophagus may be performed. 14,21 Thoracoscopic resection of thoracic esophageal duplications recently has been described in children. 65,73Mucosal integrity can be checked intraoperatively by air insufflation through a nasogastric tube. 45
Gastric Duplications Gastric duplications ideally are treated by complete excision without violation of the gastric lumen. If this is not possible, segmental gastric resection may be required. Partial excision of the duplication with mucosal stripping of the common wall may be required where the cyst is large, and complete excision would otherwise involve gastrectomy. Internal drainage (cystogastrostomy) into the stomach ~4,2I is an alternative to help avoid gastrectomy. Small pyloric duplication cysts can be excised by submucosal excision of the cyst. 22 The mucosal lining of noncommunicating cysts must be removed completely.
Duodenal Duplications Most duodenal duplications are related to the second and third patts of the duodenum on the postero-medial
AZZlE AND BEASLEY
aspect, which means that they orten are closely related to the ampulla of Vater. The significance of this is that they may be difficult to excise completely when they are in continuity with or share a common wall with the duodenum. It is an advantage to know their exact relationship to the pancreatic and biliary ducts as well as the extent of their common wall with the duodenum. These anatomic relationships can be seen preoperatively by ERCP 58 or MR cholangiography56,57 or intraoperatively by cholangiography. 14 The combined experience of the 2 largest published series of these anomalies 14,21comes to only 5 cases. Three patients were treated by partial excision and mucosectomy. The other 2 were marsupialized into the duodenum. One of the patients underwent sphincteroplasty of the pancreatic and biliary ducts, which drained into the duplication. Simple marsupialization is contraindicated where there are rests of ectopic gastric mucosa, as suggested by anemia, ulceration, or bleeding. Also, there may be risk of malignant degeneration in the long term, 64,68-7° for which reasons complete stripping or excision of the mucosal lining is preferred.
Pancreatic Duplications Enteric duplications of the pancreatic head offer challenges similar to those of duodenal duplications. Precise preoperative diagnostic imaging (abdominal ultrasonography, ERCP, angiography, and CT or MRI) 27 is important to define its anatomic relationships and assist in surgical planning. In the series reported by Siddiqui et al, 27 all 4 cysts were excised completely, although 2 had been drained initially using Roux en-Y cyst enterostomies. The investigators describe a technique of local resection, which amounted to resection of the mucosaS Black et a174found that half of the patients with pancreatic duplication cysts and ductal communication had had previous laparotomies without recognition of the correct pathology. This again highlights the importance of proper preoperative diagnostic imaging. Pancreatic duplications may be diagnosed on antenatal ultrasonography, although the correct diagnosis may remain uncertain until surgery is undertaken (Fig 3). 75 Where the duplication lies in the tail of the pancreas, laparoscopic distal pancreatectomy with splenic preservation can be performed, even in the infant. 75 SPECIAL PROBLEMS
Thoraco-Abdominal Duplications Thoraco-abdominal duplications are such rare entities that the 2 largest published series 44,21 describe a combined experience of only 9 cases. Typically, these foregut duplications are located predominantly in the chest
FOREGUT DUPLICATIONS
Fig 3. Upper abdominal ultrasound in a 3-month-old girl shows a cystic structure near the hilum of the spleen. At operation the cyst was found to be Iocated in the tail of the pancreas. C, cyst; SPL, spleen; ST, stomach.
but have an extension through the diaphragm. In these 2 series, the level at which the thoracic foregut duplication cysts communicates with the alimentary tract varied from the stomach (2 cases), to the duodenum (one case), the jejunum (4 cases), the ileum (one case), and the pancreatic duct (one case). The cysts tend to be lined in part by gastric epithelium, 21 but this is not always so. Associated anomalies include vertebral malformations and connections to the spinal canal. Given their more complex anatomic characteristics and the implications of these on surgical management, detailed diagnostic imaging is indicated. Contrast studies are useful to show the complex communications. »» In the 2 largest series, all lesions were excised through separate open thoracic and abdominal approaches. When operations are staged, adequate drainage of the residual cyst into the alimentary tract or percutaneously is necessary to avoid complications related to pressure phenomena. 14,21In the series by Stringer et al, 21 5 of 6 patients had major complications, resulting in 2 deaths. A case of antenatal ultrasonographic diagnosis of thoracoabdominal duplication cyst has been described, prompting an MRI scan to be performed shortly after birth and open thoracoabdominal approach with complete excision on the l l t h day of life) 8
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The investigation of any child with a mediastinal mass and vertebral anomalies should include adequate visualization of the spinal canal and cord. In the review reported by Superina et al, 33 all myelograms performed for children with mediastinal masses and vertebral anomalies showed intraspinal pathology. 33 Myelograms and CT myelography have been supplanted largely by the precise multiplanar capabilities of MR imaging, which not only delineates the mediastinal cyst and its relationship to other structures, but also determines the presence and extent of its intraspinal component (Fig 4). 44 The thoracic and spinal components of these complex lesions may cause significant morbidity and even mortality. There is no place for expectant management unless operative risks are considered too great. 33,76Any component that poses an immediate threat to life should be dealt with first: the next priority is where the intraspinal extension is producing neurologic signs. 33 As a general rule, laminectomy or laminotomy and excision of the intraspinal portion of the neurenteric cyst is the preferred initial surgical priority, but, in many instances, it may be performed concurrently with resection of the main component of the duplication cyst. This approach may help avoid the need for later emergency laminectomy when increasing intraspinal pressure caused by edema or bleeding in the early postoperative period produces focal neurological signs. 14'21'30'33'76'77
Diagnosis N Utero In recent years, the means to diagnose and treat large intrathoracic foregut duplications that cause mediastinal shift and hydrops in the fetus have been developed. 37 A large fetal thoracic mass can cause obstruction to venous return and produce nonimmune hydrops. Two such cases of duplication cysts diagnosed on antenatal ultrasonography have been managed in utero with thoracoamniotic shunting. 37 In one case, thoracoamniotic shunting at 28
Neurenteric Cysts Neurenteric cysts are the least common type of malformation in the spectrum of foregut duplications. Extension of the foregut duplication into the spinal canal creates specific problems and requires careful operative planning. A multidisciplinary approach involving general, thoracic, and neurosurgical expertise is required for their surgical treatment.
Fig 4. Coronal view on MRI of an upper thoracic neurenteric cyst clearly shows its spinal connection.
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AZZIE AND BEASLEY
w e e k s ' gestation was successful in that both the m e d i astinal shift and fetal hydrops resolved. Postnatally, after a period o f stabilization, the neonate u n d e r w e n t right posterolateral t h o r a c o t o m y and resection o f a large foregut duplication cyst. In the second case, t h o r a c o a m n i o t i c shunting was unsuccessful, and intrauterine fetal d e m i s e occurred. T h e indications for antenatal intervention for foregut duplication are yet to be established. In the absence o f fetal hydrops, the antenatal diagnosis of these lesions allows e x p e d i e n t postnatal investigation and early definitive m a n a g e m e n t . 3s
Major Associated Congenital Anomalies M a n y o f these patients h a v e m a j o r associated congenital anomalies, s o m e of w h i c h m a y take priority in treatment, eg, esophageal atresia and t r a c h e o e s o p h a g e a l fistula. S o m e associated m a l f o r m a t i o n s m a y be the m a j o r
determinants o f l o n g - t e r m morbidity (eg, cloacal exstrophy, anorectal anomalies, and hemivertebrae), whereas others m a y be the m a i n determinants of survival, eg, congenital diaphragmatic h e r n i a ? 1,78 CONCLUSION
T h e investigation and m a n a g e m e n t o f foregut duplications in children depends on the clinical presentation and the l e v e l of the foregut affected. In a minority of cases, urgent intervention m a y be required. Expectant m a n a g e m e n t o f a s y m p t o m a t i c lesions is not considered appropriate because m o s t e v e n t u a l l y will h a v e s y m p t o m s or complications. Although most lesions can be excised relatively simply and with minimal morbidity, more complex lesions (thoraco-abdominal duplications, neurenteric cysts) require careful preoperative delineation and m o r e c o m p l e x surgery.
REFERENCES
1. Bentley JFR, Smith JR: Developmental posterior enteric remnants and spinal malformatiorls. Arch Dis Child 35:76, 1960 2. Beardmore HE, Wigglesworth FW: Vertebral anomalies and alimentary tract duplications. Pediatr Clin North Am 5:457-474, 1958 3. Dubois VNV, Qi BW, Beasley SW, et al: Abnormal branchirlg and regression of the notochord and its relationship to foregut abnormalities. Eur J Pediatr Surg 12:83-39, 2002 4. Qi BQ, Beasley SW: Relationship of the rlotochord to foregut development in the fetal rat modeI of esophageal atresia. J Pediatr Surg 34:1593-1598, 1999 5. Williams AK, Qi BQ, Beasley SW: Demonstration of abnormal notochord development by 3D reconstructive imaging in the rat model of oesophageal atresia. Pediatr Surg Int 17:21-24, 2001 6. Orford J, Manglick P, Cass DT, et al: Mechanisms for the development of esophageal atresia. J Pediatr Surg 36:985-994, 2001 7. Arsic D, Qi BQ, Beasley SW: Hedgehog in the human: A possible explanation for the VATER associatiorl. J Pediatr Child Health 38:117121, 2002 8. Arsic D, Keenan J, Beasley SW, et al: Expression of Shh protein in the rat foregut varies according to the embryological stage. ANZ J Surg 72:A76, 2002 (suppl) 9. Beasley SW, Diez-Pardo, Qi BQ, et al: The contributiorl of the adriamycin-induced rat model of the VATER association to out understanding of congenital abnormalities and their embryogenesis. Pediatr Surg Int 16:465-472, 2000 10. Qi BQ, Beasley SW: Communicating bronchopulmonary foregut malformations in the adryamycin-induced rat model of oesophageal atresia. Aust NZ J Surg 69:56-59, 1999 11. Gerle RD, Jaretzki A, Ashley CA, et al: Congenital bronchopulmonary-foregut malformation: Pulmonary sequestration commrlnicating with the gastrointestinal tract. N Engl J Med 278:1413-1419, 1968 12. Nobrlhara KK, Gorski YC, LaQuaglia MP: Bronchogenic cysts and oesophageal duplications: Common origins and treatment. J Pediatr Surg 32:1408-1413, 1997 13. Kim KW, Kim WS, Chedn JE, et al: Complex pulmonary foregut malformation: Extralobar pulmonary sequestration associated with a duplication cyst of mixed bronchogenic and oesophageal type. Pediatr Radiol 31:265-268, 2001 14. Holcomb GW III, Gheissari A, O'Neil JA: Surgical management of alimentary tract duplications. Ann Surg 209:167-174, 1989
15. Gensler S, Seiderlberg B, Rifkin H, et al: Ciliated Iined intramural cyst of the stomach: Case report and suggested embryogenesis. Ann Surg 163:954-956, 1966 16. Kim DH, Kim JS, Nato ES, et al: Foregut duplication cyst of the stomach. Path Int 50:142-145, 2000 17. Laraja RD, Rothenberg RE, Chapman J, et al: Foregut duplication cyst: A report of a case. Am Surg 61:840-841, 1995 18. Shireman PK: Intramural cyst of the stomach. Hure Pathol 18:857-858, 1987 19. Takahara T, Torigoe T, Haga H, et al: Gastric duplication cyst: Evaluation by endoscopic ultrasonography and magrletic resonance imaging. J Gastroenterol 31:420-424, 1996 20. McNally J, Charles AK, Spicer RD, et al: Mixed foregut cyst associated with esophageal atresia. J Pediatr Surg 36:939-940, 2001 21. Stringer MD, Spitz L, Abel R, et al: Management of alimentary tract duplication in children. Br J Surg 82:74-78, 1995 22. Heiss K: Intestinal duplications, in Oldham KT, Colombarli PM, and Foglia RP (eds): Surgery of Infants and Children: Scientific Principles and Practice. Philadelphia, PA, Lippirlcott-Raven, 1997, pp 1265- 1274 23. Brown RL, Azizkharl RG: Gastrointestinal bleeding in infants and children: Meckel's diverticulum and intestinal duplication. Semin Pediatr Surg 8:202-209, 1999 24. Kammerer GT: Duplication of the stomach resembling hypertrophic pyloric sterlosis. JAMA 207:2101-2102, 1969 25. Ramsey GS: Enterogenous cyst of the stomach simulating hypertrophic pyloric stenosis. Br J Surg 44:632, 1957 26. Lavine JE, Harrison M, Heyman MB: Gastrointestinal drlplications causing relapsing pancreatitis in children. Gastroenterology 97: 1556-1558, 1989 27. Siddiqui AM, Shamberger RC, Filler RM, et al: Enteric duplications of the parlcreatic head: Definitive management by Iocal resection. J Pediatr Surg 33:1117-1121, 1998 28. Williams WH, Hendren WH: Intrapancreatic duplication causing pancreatitis in a child. Surgery 69:708-715, 1971 29. Esposito G: Diagnosis of mediastinal masses and principles of surgical tactics and techniques for their treatment. Semin Pediatr Surg 8:54-60, 1999 30. Alrabeeah A, Gillis DA, Giacomantonio M, et al: Neurenteric cysts--A spectrum. J Pediatr Surg 33:752-754, 1998
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31. Fernandes ET, Custer MD, Burton EM, et al: Neurenteric cyst: Surgery and diagnostic imaging. J Pediatr Surg 26:108-110, 1991 32. Gilchrist BF, Harrison MW, Campbell JR. Neurenteric cyst: Current management. J Pediatr Surg 25:1231-1233, t990 33. Superina RA, Ein SH, Humpreys RP: Cystic duplications of the esophagus and neurenteric cysts. J Pediatr Surg 19:527-530, 1984 34. Opsahl T, Berman EJ: Bronchogenic mediastinaI cysts in infants: Case report and review of the literature. Pediatr 30:372-377, 1962 35. Durand C, Bandain P, Pin I, et al: Usefulness of ultrasonography (US) in the diagnosis of a mediastinal opacity. Pediatr Pulmonol 16:56-57, 1997 (suppI) 36. Kuzo RS, Ben-Ami TE, Yousefzadeh DK, et al: Internal mammary compartment: Window to the mediastinum. Radiology 195:187192, 1995 37. Ferro MM, Milner R, Voto L, et aI: Intrathoracic alimentary tract duplication cysts treated in utero by thoracoamniotic shunting. Fetal Diagn Ther 13:343-347, 1998 38. Markert DJ, Grumbach K, Haney PJ: Thoracoabdominal duplication cyst: Prenatal and postnatal imaging. J Ultrasound Med 15:333336, 1996 39. Blackader AD, Evans DJ: A case of mediastinal cyst producing compression of the trachea, ending fatally in an infant of nine months. Arch Pediatr 28:194-200, 1911 40. Maier H: Bronchogenic cysts of the mediastinum. Ann Surg 127:476-501, 1948 41. Van Dam J, Rice TW, Sivak MV: Endoscopic ultrasonography and endoscopically-guided needle aspiration for the diagnosis of upper gastrointestinal tract foregut cysts. Am J Gastroenterol 87:762-765, 1992 42. Dennie CJ, Cobelntz CL: The trachea: Normal anatomic features, imaging and causes of displacement. Can Assoc Radiol J 44:8189, 1993 43. Shamberger RC, Holzman RS, Griscom NT, et al: Prospective evaluation by computed tomography and pulmonary function tests of children with mediastinal masses. Surgery 118:468-471, 1995 44. Haddon MJ, Bowen A: Bronchopulmonary and neurenteric forms of foregut anomalies. Imaging for diagnosis and management. Radiol Clin North Am 29:241-254, 1991 45. Cioffi U, Bonav]na L, DeSimone M, et al: Presentation and surgical management of bronchogenic and oesophageal duplication cysts in adults. Chest 113:1492-1496, 1998 46. Ott DJ, Wolfman NT, Wu WC, et al: Endoscopic ultrasonography of benign oesophageal cysts simulating leiomyoma J Clin Gastroenterol t5:85-87, 1992 47. Olsen L, Anneren G, Henze A, et al: Multiple intestinal duplications in a child with thoracic myelomeningocele and hydrocephalus. Eur J Pediatr Surg 2:45, 1992 48. Pokomy WJ, Goldstein IR: Enteric thoracoabdominal duplications in children. J Thorac Cardiovasc Surg 87:821-824, 1984 49. Wolf YG: Thoraco-abdominal enteric duplication with meningocele, skeletal anomalies and dextrocardia. Eur J Pediatr 149:786, 1990 50. Barr LL, Hayden CK, Stanberry SD, et al: Enteric duplication cysts in children: Are their ultrasonographic wall characteristic diagnosis? Pediatr Radiol 20:326-328, 1990 51. Holstege A, Banner S, Brambs HJ, et al: Relapsing pancreatitis associated with duodenaI wall cysts. Gastroenterology 88:814-819, 1985 52. McAlister WH, Siegel MJ: Pediatric radiology case of the day. Case 1--Dnodenal duplication. AJR 152:1328-1332, 1989
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53. Procacci C, Portuese A, Fugazzola C, et al: Duodenal duplication in the adult: Its relationship with pancreatitis. Gastrointest Radiol 13:315-322, 1998 54. Dittrich JR, Spottswood SE, Jolles PR: Gastric duplication cyst. Scintigraphy and correlative imaging. Clin Nucl Med 22:9396, 1997 55. Herman TE, Oser AB, McAlister WH: Tubular communicating duplications of esophagus and stomach. Pediatr Radiol 21:494-496, 1991. 56. Laor T, Hoffer FA, Farmamillo D, et al: Pediatric applications of MR cholangiography. Presented at the meeting of the Society for Pediatric Radiology, Washington DC, April 1995 57. Okuyama H, Matsuo Y, Fukui Y, et al: Intrapancreatic duodenal duplication associated with pancreatic pseudocysts. J Pediatr Surg 27:1573-1574, 1992 58. Filston HC, McLeod ME, Bolman III RM, et al: Improved management of pancreatic lesions in children aided by ERCP. J Pediatr Surg 15:121-128, 1980 59. Luckman KF, Welch RW, Schwesinger W, et al: Symptomatic duodenal duplication cyst in an adult demonstrated by endoscopic retrograde cholangiopancreatography. Am J Gastroenterol 72:153-159, 1979 60. Seibert JJ, Williamson SL: Gastrointestinal scintigraphy, in Miller J, Gelfand M (eds): Pediatric Nuclear Imaging, Philadelphia, PA, Saunders, 1994, pp 157-194 61. Zimmer WD, Kamida CB, McGough PF, et al: Mediastinal duplication cyst. Percutaneous aspiration and cystography for diagnosis and treatment. Chest 90:772-773, 1986 62. St Georges R, Deslauriers J, Duranceau A: Clinical spectrum of bronchogenic cysts of the mediastinum and lung in the adult. Ann Thorac Surg 52:6-i3, 1991 63. Iyer CP, Mahour GH: Dnplications of the alimentary tract in infants and children. J Pediatr Surg 30:1267-1270, 1995 64. Bolton JWR, Shahian DM: Asymptomatic bronchogenic cysts: What is the best management?. Ann Thorac Surg 53:11341137, 1992 65. Merry C, Spurbeck W, Lobe TE: Resection of foregut-derived duplications by minimal-access surgery. Pediatr Surg Int 15:224-226, 1999 60. Pober JM, Bleicher MA: Surgical management of duodenal duplication cyst simulating pyloric stenosis Mount Sinai J Med 51:702704, 1984 07. Kleinhaus S, Boley SJ, Winslow P: Occult bleeding from a perforated gastric duplication in an infant. Arch Surg 116:122, 1981 68. Chuang MT, Barba FA, Kaneko M, et al: Adenocarcinoma arising in an intrathoracic dnplication cyst of foregut origin: A case report with review of the literature. Cancer 47:1887-1890, 1981 69. Coit DG, Mies C: Adenocarcinoma arising within a gastric duplication cyst. J Surg Oncol 50:274-277, 1992 70. Ware GW, Conrad HA: Thoracic duplication of the ailmentary tract. Am J Surg 86:264-272, 1953 71. Fumkawa K, Takahata S, Ichimiya H, et al: Video-assisted thoracoscopic resection of a mediastinal cyst: Report of a case. Surg Today 24:923-925, 1994 72. Schwartz CD, Puschmann R, Eckmayr J, et al: Videoendoscopic removaI of a mediastinal cyst. Chest 105:1254-1256, 1994 73. Michel JL, Revillon Y: Therapeutic thoracoscopic procedures in children: Indications and surgical applications in lung and mediastinum, in Bax NMA, Georgeson GE, Najmaldin AS, et al (eds): Endoscopic Surgery in Children. New York, NY, Springer 1999, pp 98-108
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74. Black PR, Welch KJ, Eraklis AJ: Juxtapancreatic intestinalduplications with pancreatic ductal communication: A cause of pancreatitis and recurrent abdominal pain. J Pediatr Surg 2t:257261, 1986 75. Maoate K, Azzie G, Beasley SW: Technique of laparoscopic distal pancreatectomy with splenic preservation in the infant. ANZ J Surg 72:A81, 2002 (suppl)
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76. Sen S, Boume AJ, Morris LL, et al: Dorsal enteric cysts--A study of eight cases. Austr NZ J Surg 58:51-55, 1988 77. Thurston SE, Lenn NJ: The association of spinn and gastroesophageal anomalies: Case report and review. Clin Pediatr 23:652-654, 1984 78. Danzer E, Paek BW, Farmer DL, et al: Congenital diaphragmatic hemia associated with a gastroesophageal duplication cyst: A case report. J Pediatr Surg 36:626-628, 2001
Copyright 2003, Elsevier Science (USA). All rights reserved.
HE PRIMITIVE FOREGUT gives rise to the pharynx and its derivatives, the respiratory tract (trachea and lungs), esophagus, stomach, and duodenum to the level of the ampulla of Vater. No single embryologic theory explains the spectrum of anomalies covered by the heading "foregut duplications." The split notochord theory 1,2 is an attractive explanation for some alimentary tract and spinal anomalies, eg, neurenteric canal, but does not explain the full spectrum of lesions observed. The notochord appears to have a pivotal role to play in foregut development34 as the organizer of paraxial organogenesis. There is some evidence emerging that altered expression of the sonic hedgehog gene by the notochord affects the Shh-GLi signalling pathway and may contribute to a spectrum of bronchopulmonary, alimentary tract and associated anomalies (including esophageal atresia, pulmonary sequestrations, and cervical hemivertebrae)Y Bronchopulmonary foregut malformations have
T
been observed in the Adriamycin-induced rat model of the VATER association. 9J° The exact embryogenesis of foregut duplications remains to be determined. THE SPECTRUM OF FOREGUT DUPLICATIONS
In 1968, Gerle et al u proposed that the term bronchopulmonary foregut malformations be used to encompass the full spectrum of developmental aberrations of the embryonic foregut. The termforegut cyst 12is used today to describe a spectrum of bronchopulmonary malformations, typically bronchogenic cysts and combined pulmonary sequestrations associated with mixed bronchogenic and esophageal duplications 13 as well as the more traditional duplications of the alimentary tract from the pharynx to the duodenum. The classical features of alimentary tract duplications are that they have (1) a welldeveloped coat of smooth muscle, (2) an epithelial lining representing some portion of the alimentary tract (unless destroyed by infection), and (3) an intimate attachment to some portion of the foregut. The classical definition of foregut duplications has difficulty accommodating all variations, such as esophageal duplications that lie adjacent to or distant from the esophagus without sharing a muscular wall with it, TM or bronchogenic cysts containing cartilage that are attached to the wall of the lower esophagus, far away fi'om any bronchus. Typically, the mucosal lining of a foregut duplication is that of the respiratory or alimentary tract, but it can vary anywhere from ectopic respiratory pseudostratified ciliated columnar epithelium to ectopic gastric foveolar epithelium with fundic or pyloric glands. All may coexist in a single malformation. 1>19 Proof of the hybrid nature of some of these lesions is that gastric duplications can be lined with pseudostratified ciliated columnar (respiratory) epithelium, 16 and esophagogastric lesions can be lined with smooth muscle and cartilage as well as tissue resembling disorganized bronchioles with combined ciliated and squamous epithelium. 2° CLINICAL PRESENTATION
From the Department of Paediatric Surgery, Christchurch Hospital, Christchurch, New Zealand. Address reprint requests to Professor Spencer Beasley, MS, FRACS, Department of Paediatric Surgery, Christchurch Hospital, Private Bag 4710, Christchurch, New Zealand. Copyright 2003, Elsevier Science (USA). All rights reserved. 1055-8586/03/1201-0006535.00/0 dei: 1O.1053/spsu.2003.50000 46
The mode of presentation of symptomatic foregut duplications depends on 3 factors: (1) the anatomic level of the foregut involved, (2) the mass effect of the lesion, and (3) specific complications related to the malformation (usually associated with its mucosal lining containing acid secreting cells). Seminars in Pediatric Surgery, Vol 12, No 1 (February), 2003: pp 46-54
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Intrathoracic Duplications
Pancreatic Duplications
Most foregut duplications are located in the thorax. Nonspecific symptoms of pain or discomfort often are secondary to their space-occupying effect mainly because enlargement occurs in a relatively confined space (as with bronchogenic cysts and esophageal duplications in the posterior mediastinum). As the lesion enlarges further, symptoms related to compression of adjacent structures may become more specific and include cough, wheezing, dyspnea, hemoptysis, recurrent infections (caused by airway compression), and dysphagia (caused by esophageal compression). Gastric mucosa lining a foregut duplication is well known to cause symptoms: it occurs in about one third of esophageal duplications. 14 Although it may be an incidental finding in some cases, gastric mucosa also may lead to ulceration and bleeding within the cyst 14 or produce a peptic esophageal stricture. 21 Many foregut duplications are identified on routine imaging in an asymptomatic patient or even prenatally by ultrasonography. This is especially true of bronchogenic cysts, esophageal duplications, and extralobar pulmonary sequestrations, which present frequently as incidental findings on routine chest x-ray.
The mass effect of a duplication in the head of the pancreas may cause abdominal pain and features of pancreatitis. 2°,26-28 Ectopic gastric mucosa in foregut duplication cysts involving the pancreatic head in 2 patients has been found to produce increased levels of gastrin and gastritis. 27
Gastric Duplications Gastric duplications are rare, accounting for about 5% of abdominal duplications. 22 The typical presentation is of vomiting from gastric outlet obstruction and a palpable epigastric mass. An upper abdominal mass is palpable in up to 50% of cases. 21 Although vomiting is the most common presentation of gastric duplications, hematemesis and melena are not uncommon. ~4,2I Persistent vomiting may mimic pyloric stenosis and is caused by gastric outlet compression. 23-25Some gastric duplications are completely separate from the stomach within the retroperitoneum. Most do not communicate with the lumen of the stomach. Weight loss may be secondary to dehydration and malnutrition from protracted vomiting. Peptic ulceration may cause pain. Bleeding and perforation are the most common complications of gastric duplications and may be the only symptoms at first presentation. About a third are diagnosed in the neonatal period; the rest present throughout childhood.
Duodenal Duplications Duodenal duplications are rare and difficult to diagnose. Most patients have a long history of vague and nonspecific symptoms or intermittent obstruction. Most duodenal duplications are cystic, but a few communicate with the duodenum. Some present with jaundice from extrinsic compression of the common bile duct.
DIAGNOSTIC IMAGING
Intrathoracic Lesions Foregut duplications in the chest are best investigated initially with a chest x-ray. Posterior-anterior and lateral views are able to detect lesions in over 90% of cases (Fig lA). 29 Vertebral anomalies, if present, increase the chances that a lesion seen on chest x-ray is a foregut duplication and that there may be associated spinal anomalies (neurenteric canal). 3°-33 In one series 12 of 58 patients with bronchopulmonary foregut malformations (either bronchogenic cysts or esophageal duplications) 47 had abnormal chest radiograph findings: 86% of these consisted of either a posterior mediastinal mass or a parenchymal lung lesion, whereas the remainder were related to the space-occupying mass effect of the cyst or to a secondary pneumonic (infective) process. Others have reported similar findings. 34 Thoracic ultrasonography, especially in younger children, may identify some small anterior and central opacities undetected on standard chest x - r a y s . 29,35,36 However, ultrasonography is of limited value in the detection of most posterior mediastinal lesions 29 and is not performed routinely. Antenatal ultrasonography has been successful in the detection of intrathoracic foregut duplication cysts in 2 fetuses with hydrops. 37 This modality also has detected a thoraco-abdominal duplication cyst as an incidental finding on routine antenatal examination, allowing early postdelivery management. 38 Contrast studies (eg, barium swallow) may show a mass effect, as shown by compression of the esophagus or displacement from normal alignment, and may be used to determine whether there is any communication with the esophagus, although this is rare. 39-41 A computed tomography (CT) scan enables evaluation of mediastinal organs in a transverse plane and helps establish the borders of the lesion and its relationship to normal structures (Fig 1B). 42'43 The CT also has a role in screening cases in which the chest x-ray has been uncertain or equivocal. The scan evaluates the density of the lesion and, with IV contrast, shows whether the lesion perfuses, ie, provides information about its vascularity. The spiral CT provides the best definition of relationships of the bronchial tree and gives 3-dimensional reconstructions of mediastinal masses? 9
48
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Fig 1. (A) Posterior-anterior chest x-ray of a 5-year-old girl shows a well-defined circular opacity in the left hemithorax posteriorly, partly obscured by the left hemidiaphragm and left heart border. (B) Transverse section on CT of the Iower chest shows the same lesion as in Fig l A at the left lung base, There are no obvious abnormal vessels supplying it. (C) MRI scan (TzW) of the chest, coronal plane, shows an oval cystic lesion at the left base posteriorly and medially, There is no evidence of a connection with the esophagus or spinal canal, and no associated vessels can be seen (same patient as l A and 1B).
Magnetic resonance imaging (MRI) is valuable in the diagnosis of intrathoracic lesions in children because it helps avoid exposure to ionizing radiation, and its sagittal and coronal scans provide accurate information about the vascular anatomy without the need for IV contrast (Fig lC). 13'29 For example, it may show the aberrant vessel supplying a pulmonary sequestration. It is particularly useful for detecting associated anomalies of the spine, such as neurenteric canal. MRI has largely replaced myelograms and CT myelography in the diagnostic imaging of neurenteric forms of foregut anomalies. It defines the relationship to surrounding structures precisely and detects anomalies of the spinal column and the spinal cord. 44 Drawbacks in its use are that children frequently require general anaesthesia or sedation for the procedure, and it is unsuitable for examination of the bronchial tree. Where the bronchopulmonary foregut malformation is complex, MRI best shows the relationship between different components of the mass. 13
In the adult literature, endoscopic ultrasonography has been used to diagnose mediastinal cysts and to determine whether an esophageal impression is intramural or extrinsic to the esophageal wall. 41,45,46 There is little experience using this technique in children.
Intraabdominal Lesions The imaging of foregut duplications below the diaphragm is particularly amenable to ultrasonography. Screening for the intraabdominal extension or separate intestinal duplication that may accompany intrathoracic duplication cysts 14,47-49 is best done with abdominal ultrasonography. 5°43 This association was reported in 30% of the thoracic duplications in one series, but is uncommon in other reports. Duplications are identified by their gut signature, a term that is used to describe the hyperechoic inner layer that is produced by the mucosa and the relatively hypoechoic outer layer produced by smooth muscle. 5°-53 Peristaltic activity within the structure of the
FOREGUT DUPLICATIONS
cyst also may be visible. »4 Further investigation using other imaging modalities may better define the location, size, and precise anatomic relationships of the lesion to surrounding structures. Endoscopic ultrasonography has been shown to be accurate but invasive. 19 Contrast studies can show communication between the duplication and the intestinal tract as well as shed light on complex anatomic relationships. 65 A CT scan is an alternative modality to identify the precise location and size of the lesion and give information about its effects on surrounding structures, such as edema of the pancreas with duplication of the pancreatic head.51,53 MRI offers little in the way of further information unless characterization of the biliary-pancreatic system is required. In this case, MR cholangiography is a noninvasive way to detect abnormalities »6,57 and may give results comparable with those of endoscopic retrograde cholangiopancreatography (ERCP)? 7 However, the latter remains the gold standard to outline choledochal and pancreatic ductal anatomy and show any communication between the duplication cyst and the main pancreatic duct. 58,»9 Intraoperative ultrasonography may assist in the localization of cysts not easily visible in the pancreas, and intraoperative pancreatography may be useful to outline adjacent ductal relationships. Nuclear medicine studies (technetium 99 scanning) have been used to diagnose gastric duplications, but there are limitations to this technique because of the normal gastric uptake of isotope. 23 The sensitivity of detecting ectopic gastric mucosa with 99m Tc pertechnetate approaches 85% and is best when the patient is pretreated with cimetidine or glucagon. 6° A disosopropyl-acetanilide iminodiacetic acid (DISIDA) scan may help distinguish a duodenal duplication from a choledochal cyst. 22 Variation in the radiologic expertise and technical equipment available may affect the diagnostic algorithm that is used from center to center. RATIONALE FOR SURGICAL EXCISION
In general, foregut duplications should be excised. In incidentally diagnosed foregut duplications, particularly bronchogenic cysts, their usually benign course has encouraged some to advocate less invasive treatment such as needle aspiration and injection of a sclerosing agent, 27,61 but there are no good long-term follow-up data available. Orte large adult study has found that 82% of foregut duplication cysts were either symptomatic, complicated, or both at the time of surgery, and that they were associated with a high rate of intraoperative complications (14%), including division of the vagus nerve
49
and injuries to the esophagus and bronchus. 62 This led the investigators to recommend early resection when these lesions are first identified. In children, expectant management of asymptomatic lesions is not considered appropriate because most eventually will have symptoms or complications. The nature of the complication varies according to the level of the foregut affected: features include feeding difficulties with floor of mouth lesions, 63 airway-related problems, 64,65 dysphagia, 21 and vomiting mimicking pyloric stenosis. 24,66,25Thoracic lesions are of concern because they occupy space otherwise destined for growing respiratory tissue. 64 Pneumonia is a common sequela to bronchogenic duplications. 65 Foregut duplications within the pancreas can cause pancreatitis by virtue of their mass effect. 2628 Complications unrelated to the mass effect of the duplication include (1) bleeding (related to ectopic gastric mucosa) either within the duplication itself or in adjacent alimentary tract, 14'21'67 (2) perforation of the duplication, 67 (3) peptic esophageal stricture, 2J and (4) malignant transformation. 64,68-7°There is general consensus thät foregut duplications are best excised becanse of their propensity to produce complications. SURGICAL TREATMENT
The most practical approach to the treatment of foregut duplications is one based on the anatomic level at which it is predominantly located.
Thoracic Duplications The main issues surrounding the surgical approach to intrathoracic foregut duplications relate to whether the lesions are best removed via an open thoracotomy or with video-assisted thoracoscopic surgery. The other concern is that some have a concomitant, intraabdominal component] 4,47-49 Any intraabdominal extension is best identified pre-operatively because this may affect the choice of surgical approach. Bronchogenic cysts. Traditionally, bronchogenic cysts have been resected via open thoracotomy, usually by a posterolateral intercostal approach. The procedure normally is straightforward unless the cyst has been infected and is surrounded by inflammatory changes. In recent years, minimal access surgical techniques have been applied to these lesions in both adults vl,72 and children. 6» Descriptions of minimal access surgical techniques have highlighted the importance of complete resection (to reduce the risk of recurrence) and identified an incidence of post resection pneumothorax associated with centrally located bronchogenic cysts. Merry et a165 described persistent air leak in 2 of 8 children; although this is a small series, it does constitute the largest experience reported
50
Fig 2. Operative appearance of a tubular duplication of the esophagus: it shared part of its wall with the normal esophagus.
of foregut-derived duplications resected by minimal access surgery. The investigators have suggested that central mediastinal lesions require chest robe drainage postoperatively.65 Esophageal duplications. Open right thoracotomy and resection has been the standard treatment for esophageal duplications (Fig 2). In the largest published series, 20 of 2 1 patients underwent successful primary resection of the duplications that were dissected free from surrounding structures. 14 Complete excision with segmental esophageal resection may be required when the shared esophageal wall of the cyst is too intimate to allow excision of the duplication alone. 21 Alternatively, marsupilization with stripping of the mucosa of the cyst at its common wall with the esophagus may be performed. 14,21 Thoracoscopic resection of thoracic esophageal duplications recently has been described in children. 65,73Mucosal integrity can be checked intraoperatively by air insufflation through a nasogastric tube. 45
Gastric Duplications Gastric duplications ideally are treated by complete excision without violation of the gastric lumen. If this is not possible, segmental gastric resection may be required. Partial excision of the duplication with mucosal stripping of the common wall may be required where the cyst is large, and complete excision would otherwise involve gastrectomy. Internal drainage (cystogastrostomy) into the stomach ~4,2I is an alternative to help avoid gastrectomy. Small pyloric duplication cysts can be excised by submucosal excision of the cyst. 22 The mucosal lining of noncommunicating cysts must be removed completely.
Duodenal Duplications Most duodenal duplications are related to the second and third patts of the duodenum on the postero-medial
AZZlE AND BEASLEY
aspect, which means that they orten are closely related to the ampulla of Vater. The significance of this is that they may be difficult to excise completely when they are in continuity with or share a common wall with the duodenum. It is an advantage to know their exact relationship to the pancreatic and biliary ducts as well as the extent of their common wall with the duodenum. These anatomic relationships can be seen preoperatively by ERCP 58 or MR cholangiography56,57 or intraoperatively by cholangiography. 14 The combined experience of the 2 largest published series of these anomalies 14,21comes to only 5 cases. Three patients were treated by partial excision and mucosectomy. The other 2 were marsupialized into the duodenum. One of the patients underwent sphincteroplasty of the pancreatic and biliary ducts, which drained into the duplication. Simple marsupialization is contraindicated where there are rests of ectopic gastric mucosa, as suggested by anemia, ulceration, or bleeding. Also, there may be risk of malignant degeneration in the long term, 64,68-7° for which reasons complete stripping or excision of the mucosal lining is preferred.
Pancreatic Duplications Enteric duplications of the pancreatic head offer challenges similar to those of duodenal duplications. Precise preoperative diagnostic imaging (abdominal ultrasonography, ERCP, angiography, and CT or MRI) 27 is important to define its anatomic relationships and assist in surgical planning. In the series reported by Siddiqui et al, 27 all 4 cysts were excised completely, although 2 had been drained initially using Roux en-Y cyst enterostomies. The investigators describe a technique of local resection, which amounted to resection of the mucosaS Black et a174found that half of the patients with pancreatic duplication cysts and ductal communication had had previous laparotomies without recognition of the correct pathology. This again highlights the importance of proper preoperative diagnostic imaging. Pancreatic duplications may be diagnosed on antenatal ultrasonography, although the correct diagnosis may remain uncertain until surgery is undertaken (Fig 3). 75 Where the duplication lies in the tail of the pancreas, laparoscopic distal pancreatectomy with splenic preservation can be performed, even in the infant. 75 SPECIAL PROBLEMS
Thoraco-Abdominal Duplications Thoraco-abdominal duplications are such rare entities that the 2 largest published series 44,21 describe a combined experience of only 9 cases. Typically, these foregut duplications are located predominantly in the chest
FOREGUT DUPLICATIONS
Fig 3. Upper abdominal ultrasound in a 3-month-old girl shows a cystic structure near the hilum of the spleen. At operation the cyst was found to be Iocated in the tail of the pancreas. C, cyst; SPL, spleen; ST, stomach.
but have an extension through the diaphragm. In these 2 series, the level at which the thoracic foregut duplication cysts communicates with the alimentary tract varied from the stomach (2 cases), to the duodenum (one case), the jejunum (4 cases), the ileum (one case), and the pancreatic duct (one case). The cysts tend to be lined in part by gastric epithelium, 21 but this is not always so. Associated anomalies include vertebral malformations and connections to the spinal canal. Given their more complex anatomic characteristics and the implications of these on surgical management, detailed diagnostic imaging is indicated. Contrast studies are useful to show the complex communications. »» In the 2 largest series, all lesions were excised through separate open thoracic and abdominal approaches. When operations are staged, adequate drainage of the residual cyst into the alimentary tract or percutaneously is necessary to avoid complications related to pressure phenomena. 14,21In the series by Stringer et al, 21 5 of 6 patients had major complications, resulting in 2 deaths. A case of antenatal ultrasonographic diagnosis of thoracoabdominal duplication cyst has been described, prompting an MRI scan to be performed shortly after birth and open thoracoabdominal approach with complete excision on the l l t h day of life) 8
51
The investigation of any child with a mediastinal mass and vertebral anomalies should include adequate visualization of the spinal canal and cord. In the review reported by Superina et al, 33 all myelograms performed for children with mediastinal masses and vertebral anomalies showed intraspinal pathology. 33 Myelograms and CT myelography have been supplanted largely by the precise multiplanar capabilities of MR imaging, which not only delineates the mediastinal cyst and its relationship to other structures, but also determines the presence and extent of its intraspinal component (Fig 4). 44 The thoracic and spinal components of these complex lesions may cause significant morbidity and even mortality. There is no place for expectant management unless operative risks are considered too great. 33,76Any component that poses an immediate threat to life should be dealt with first: the next priority is where the intraspinal extension is producing neurologic signs. 33 As a general rule, laminectomy or laminotomy and excision of the intraspinal portion of the neurenteric cyst is the preferred initial surgical priority, but, in many instances, it may be performed concurrently with resection of the main component of the duplication cyst. This approach may help avoid the need for later emergency laminectomy when increasing intraspinal pressure caused by edema or bleeding in the early postoperative period produces focal neurological signs. 14'21'30'33'76'77
Diagnosis N Utero In recent years, the means to diagnose and treat large intrathoracic foregut duplications that cause mediastinal shift and hydrops in the fetus have been developed. 37 A large fetal thoracic mass can cause obstruction to venous return and produce nonimmune hydrops. Two such cases of duplication cysts diagnosed on antenatal ultrasonography have been managed in utero with thoracoamniotic shunting. 37 In one case, thoracoamniotic shunting at 28
Neurenteric Cysts Neurenteric cysts are the least common type of malformation in the spectrum of foregut duplications. Extension of the foregut duplication into the spinal canal creates specific problems and requires careful operative planning. A multidisciplinary approach involving general, thoracic, and neurosurgical expertise is required for their surgical treatment.
Fig 4. Coronal view on MRI of an upper thoracic neurenteric cyst clearly shows its spinal connection.
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w e e k s ' gestation was successful in that both the m e d i astinal shift and fetal hydrops resolved. Postnatally, after a period o f stabilization, the neonate u n d e r w e n t right posterolateral t h o r a c o t o m y and resection o f a large foregut duplication cyst. In the second case, t h o r a c o a m n i o t i c shunting was unsuccessful, and intrauterine fetal d e m i s e occurred. T h e indications for antenatal intervention for foregut duplication are yet to be established. In the absence o f fetal hydrops, the antenatal diagnosis of these lesions allows e x p e d i e n t postnatal investigation and early definitive m a n a g e m e n t . 3s
Major Associated Congenital Anomalies M a n y o f these patients h a v e m a j o r associated congenital anomalies, s o m e of w h i c h m a y take priority in treatment, eg, esophageal atresia and t r a c h e o e s o p h a g e a l fistula. S o m e associated m a l f o r m a t i o n s m a y be the m a j o r
determinants o f l o n g - t e r m morbidity (eg, cloacal exstrophy, anorectal anomalies, and hemivertebrae), whereas others m a y be the m a i n determinants of survival, eg, congenital diaphragmatic h e r n i a ? 1,78 CONCLUSION
T h e investigation and m a n a g e m e n t o f foregut duplications in children depends on the clinical presentation and the l e v e l of the foregut affected. In a minority of cases, urgent intervention m a y be required. Expectant m a n a g e m e n t o f a s y m p t o m a t i c lesions is not considered appropriate because m o s t e v e n t u a l l y will h a v e s y m p t o m s or complications. Although most lesions can be excised relatively simply and with minimal morbidity, more complex lesions (thoraco-abdominal duplications, neurenteric cysts) require careful preoperative delineation and m o r e c o m p l e x surgery.
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