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Wilson disease – liver pathology
Handbook of Clinical Neurology, Vol. 142 (3rd series) Wilson Disease A. Członkowska and M.L. Schilsky, Editors http://dx.doi.org/10.1016/B978-0-444-63625-6.00007-0 © 2017 Elsevier B.V. All rights reserved
Chapter 7
Wilson disease – liver pathology MACIEJ PRONICKI* Department of Pathology, The Children’s Memorial Health Institute, Warsaw, Poland
Abstract The liver in Wilson disease may demonstrate a wide range of damage patterns. Some patients may present almost no detectable microscopic pathology, while others display lesions consistent with fulminant hepatitis or acute liver failure. Most liver biopsy specimens show moderate to severe steatosis, variable degree of portal and/or lobular inflammation, and fibrosis eventually progressing to cirrhosis. Additional findings include liver cell degeneration and ballooning, Mallory hyaline bodies, liver cell necrosis, and glycogenation of periportal hepatocytic nuclei. None of the above lesions are specific for Wilson disease and should be interpreted in a wider medical context and particular clinical setting. The main message concerning liver pathology is that Wilson disease may be microscopically misinterpreted as many other liver diseases, including viral or autoimmune hepatitis, alcoholic/nonalcoholic steatohepatitis, toxic liver injury, cryptogenic cirrhosis, metabolic liver disease, and many others. The possibility of Wilson disease should be considered in all patients, especially young ones presenting unexplained liver diseases with many variable patterns of microscopic liver involvement.
PATHOLOGY OF WILSON DISEASE In a proportion of patients, particularly children, teenagers, or young adults suffering from Wilson disease, liver disease constitutes the most frequently observed clinical manifestation. The condition of the liver as an organ readily accessible by biopsy is quite well studied in Wilson disease, and histologic findings may bring about clinically useful information. Liver pathology has been widely described in medical surgical pathologic literature and constitutes the basic handbook knowledge (Arroyo and Crawford, 2009; Desmet and Rosai, 2012; Thompson et al., 2012; Torbenson, 2015). Clinical pattern of liver involvement may attain the full spectrum of presentations. Symptoms usually do not appear before the age of 3–5 years. Some patients develop acute or fulminant liver failure; on the other hand, many children and adults may stay clinically asymptomatic for a long time. The reason for phenotypic variability is not clear. This topic is widely discussed in Chapters 2–5. The following light microscopic pathologic findings, isolated or combined
in diverse associations, have been reported in patients with Wilson disease.
Liver steatosis In general, fatty degeneration is considered rather a frequent and, for the most part, unspecific expression of the liver parenchymal cell damage. In Wilson disease it is considered by many as one of the most typical features (Figs 7.2–7.7). The range of fatty accumulation may be wide, from mild and focal to severe, and diffuse. Types of steatosis – microvesicular vs. macrovesicular – also may vary, or frequently coexist. Interestingly, in some patients liver steatosis and inflammation in Wilson disease closely resemble nonalcoholic fatty liver disease, as seen in metabolic syndrome, or other forms of steatohepatitis. This phenomenon should be kept in mind when evaluating patients with liver disease, presenting steatohepatitis in biopsy, particularly if patients are young and not overweight.
*Correspondence to: Maciej Pronicki, Department of Pathology, The Children’s Memorial Health Institute, al. Dzieci Polskich 20, 04-730 Warsaw, Poland. Tel: +48-22-815-19-60, E-mail: [email protected]
Fig. 7.1. Liver biopsy sample of Wilson disease patient showing no substantial microscopic pathology. In some patients the liver is normal, or presents only minimal lesions in light microscopy. Portal space visible in upper right corner. Central vein at the left lower margin. Hematoxylin and eosin; original optical magnification 200 .
Fig. 7.4. Moderate mixed steatosis with features of early fibrosis. No substantial hepatitis. Hematoxylin and eosin; original optical magnification 200 .
Fig. 7.2. Mixed, predominantly pericentral steatosis of moderate degree, minimal portal inflammatory infiltrate. No fibrosis. Hematoxylin and eosin; original optical magnification 200 .
Fig. 7.5. Mild steatosis and inflammation with early, thin fibrous bridges. Hematoxylin and eosin; original optical magnification 100 .
Fig. 7.3. Moderate to severe diffuse fatty degeneration, portal space widened by lymphocytic inflammatory infiltration. No interface inflammatory activity. Hematoxylin and eosin; original optical magnification 200 .
Fig. 7.6. Severe mixed fatty degeneration with no fibrosis and no hepatitis. Hematoxylin and eosin; original optical magnification 200 .
WILSON DISEASE – LIVER PATHOLOGY
Fig. 7.7. Diffuse fatty liver with moderate fibrosis and no inflammation. Hematoxylin and eosin; original optical magnification 100 .
Fig. 7.8. Severe active inflammation with parenchymal destruction and fibrosis, steatosis. Hematoxylin and eosin; original optical magnification 200 .
Inflammation Noninfectious hepatitis of any kind and degree may be observed in Wilson disease. In terms of histologic pattern, liver involvement may attain any form of acute or chronic inflammation, including forms mimicking viral, autoimmune, or other form of hepatitis (Fig. 7.8). Inflammatory infiltrates may occupy portal spaces, sometimes with accompanying active interface hepatitis. Inflammatory cells may be also seen in intralobular areas, leading to damage and necrosis of small groups of hepatocytes (Figs 7.9 and 7.10). Both portal and lobular hepatitis may coexist in individual patients (Fig. 7.11).
Fibrosis and cirrhosis Liver fibrosis usually progresses with the development of copper deposition and consequent liver damage (Fig. 7.12). Several authors discern precirrhotic and
73
Fig. 7.9. Massive liver cell necrosis with numerous neocholangioles and diffuse scarring, with no features of liver cell regeneration (explant). Hematoxylin and eosin; original optical magnification 100 .
Fig. 7.10. High-power magnification of Fig. 7.11 (explant). Irreversible liver cell damage, neocholangioles with bile plugs, diffuse fibrosis, and inflammation. Hematoxylin and eosin; original optical magnification 400 .
cirrhotic phases of liver disease in Wilsonian patients. Initially, fibrous tissue expands portal tracts and forms thin perisinusoidal fibrous strands, then fibrous bridges develop. Later in the disease, full-blown cirrhosis may develop (Fig. 7.13). The cirrhosis in Wilson disease is usually macronodular.
Glycogenated nuclei Glycogen deposition inside the liver cell nucleus is described as one of the typical findings in Wilson disease. Glycogenated nuclei may be observed both in light and electron microscope, and are visible in periportal areas of the liver lobule (Fig. 7.14). However, this observation is highly nonspecific, also occurring in many other liver diseases.
74
M. PRONICKI
Necrosis Individual hepatocytic cell necrosis may be observed in scattered cells in many cases of Wilson disease. In rare instances of fulminant liver failure, the necrosis is massive and diffuse. In such instances, the liver cell regeneration is usually nonexistent, with diffuse neocholangiolization and fibrosis.
Ballooning degeneration
Fig. 7.11. Intralobular foci of inflammatory liver cell dropout, mixed steatosis. Hematoxylin and eosin; original optical magnification 400 .
This type of liver cell injury consists of cell enlargement with cytoplasm clearing (Fig. 7.15). It is typically observed in some types of fatty liver disease and steatohepatitis, as well as liver inflammation. Thus, ballooned hepatocytes, although seen in Wilson disease, are not specific for this disorder.
Fig. 7.12. Severe fibrosis with nodular transformation and relatively scant inflammatory infiltrate. Moderate to severe mixed steatosis. Hematoxylin and eosin; original optical magnification 200 .
Fig. 7.14. Glycogenated liver cell nuclei of ballooned and steatotic liver cells. Hematoxylin and eosin; original optical magnification 600 . The arrow shows one of the glycogenated liver cell nuclei present in the microphotograph.
Fig. 7.13. Liver cirrhosis with dispersed mild inflammatory cells; original optical magnification 100 . Periodic–acid Schiff stain with diastase digestion (explant).
Fig. 7.15. Liver cell ballooning (center) and steatosis, leading to effacement of trabecular architecture. Hematoxylin and eosin; original optical magnification 600 .
WILSON DISEASE – LIVER PATHOLOGY
Mallory bodies Mallory hyaline bodies, of the same type and morphology as classically seen in ballooned hepatocytes in alcoholic fatty liver disease and other chronic liver diseases, may be observed in Wilson disease. They consist of intracytoplasmic eosinophilic inclusions built of cytoskeletal proteins, mainly keratins. All of the above-mentioned individual histologic findings in Wilson disease may combine to form several large “biopsy patterns” (Torbenson, 2015). The most typical and well-defined are: (1) predominantly steatosis/ steatohepatitis-type damage with variable degree of fibrosis; (2) unexplained cirrhosis or hepatic fibrosis; (3) acute or fulminant hepatitis; and (4) mild, borderline pathologic lesions or even normal liver histology (Fig. 7.1).
LIGHT MICROSCOPIC DETECTION OF COPPER DEPOSITS Copper deposits in the liver are not detectable in routine sections stained with hematoxylin and eosin. In light microscopy, accumulated copper and associated proteins may be visualized by special histochemical stains. The most widely used and recognized are rhodanine and orcein. The first stain shows orange-red material accumulated in hepatocytic cytoplasm; the second stains excessive copper binding protein in brown. However, due to the focal pattern of copper accumulation in the liver, the sensitivity of the above stainings in biopsy specimens may be unsatisfactory. Moreover, copper may accumulate in liver cells in disorders other than Wilson disease, e.g., chronic cholestatic states. In the author’s experience, copper staining does not appear useful as a diagnostic tool in everyday diagnostic lab work.
ULTRASTRUCTURE Although the golden era of transmission electron microscopy in pathologic diagnostics has already passed, it should be noticed that ultrastructure of liver in Wilson disease is considered quite typical, and recognition of its pattern may appear diagnostically useful (Phillips et al., 1987). The most striking are the mitochondrial lesions. The mitochondria are enlarged, have abnormal shapes, and characteristically dilated terminal cristae
75
sometimes containing floccular deposits. Bile canaliculi show elongation of microvilli, sometimes with features of luminal obstruction, as well as “fish-mouth” outline. Other lesions include electron-dense intracytoplasmic inclusions, lysosomal copper deposits, glycogenated periportal hepatocytic nuclei, steatosis, and Mallory bodies. All of the above features may be suggestive of Wilson disease when observed together, in corresponding clinical setting. None of the described ultrastructural observations is diagnostic as an isolated finding. More about the role of liver pathology in clinical symptoms and diagnosis of WD is given in Chapters 9 and 14.
SUMMARY Since the hepatolenticular degeneration is considered a treatable disease, one message should be kept in mind: any acute or chronic liver injury of unknown origin presenting any kind and degree of histologic damage, particularly in a child or young person, should raise the suspicion of Wilson disease and prompt proper differential diagnostic action. This is particularly important when liver disease coexists with neuropsychiatric symptoms.
REFERENCES Arroyo M, Crawford J (2009). Pediatric liver disease and inherited, metabolic, and developmental disorders of the pediatric and adult liver. In: R Odze, J Goldblum (Eds.), Surgical Pathology of the GI tract, Liver, Biliary Tract and Pancreas, Saunders Elsevier, Philadelphia, pp. 1281–1283. Desmet V, Rosai J (2012). Liver, non-neoplastic diseases, tumors and tumorlike conditions. In: J Rosai (Ed.), Rosai and Ackerman’s Surgical Pathology, Mosby Elsevier, Philadelphia, PA, p. 899. Phillips M, Poucell S, Patterson J et al. (1987). The liver: an ultrastructural atlas and text of liver diseases, Raven Press, New York, pp. 255–256. Thompson R, Portmann B, Roberts E (2012). Genetic and metabolic liver disease. In: A Burt, B Portmann, L Ferrell (Eds.), Mac Sween’s Pathology of the Liver, Edinburgh, Churchill Livingstone Elsevier, pp. 203–208. Torbenson M (2015). Biopsy interpretation of the liver, Wolters Kluwer, Philadelphia, pp. 234–327.
Chapter 7
Wilson disease – liver pathology MACIEJ PRONICKI* Department of Pathology, The Children’s Memorial Health Institute, Warsaw, Poland
Abstract The liver in Wilson disease may demonstrate a wide range of damage patterns. Some patients may present almost no detectable microscopic pathology, while others display lesions consistent with fulminant hepatitis or acute liver failure. Most liver biopsy specimens show moderate to severe steatosis, variable degree of portal and/or lobular inflammation, and fibrosis eventually progressing to cirrhosis. Additional findings include liver cell degeneration and ballooning, Mallory hyaline bodies, liver cell necrosis, and glycogenation of periportal hepatocytic nuclei. None of the above lesions are specific for Wilson disease and should be interpreted in a wider medical context and particular clinical setting. The main message concerning liver pathology is that Wilson disease may be microscopically misinterpreted as many other liver diseases, including viral or autoimmune hepatitis, alcoholic/nonalcoholic steatohepatitis, toxic liver injury, cryptogenic cirrhosis, metabolic liver disease, and many others. The possibility of Wilson disease should be considered in all patients, especially young ones presenting unexplained liver diseases with many variable patterns of microscopic liver involvement.
PATHOLOGY OF WILSON DISEASE In a proportion of patients, particularly children, teenagers, or young adults suffering from Wilson disease, liver disease constitutes the most frequently observed clinical manifestation. The condition of the liver as an organ readily accessible by biopsy is quite well studied in Wilson disease, and histologic findings may bring about clinically useful information. Liver pathology has been widely described in medical surgical pathologic literature and constitutes the basic handbook knowledge (Arroyo and Crawford, 2009; Desmet and Rosai, 2012; Thompson et al., 2012; Torbenson, 2015). Clinical pattern of liver involvement may attain the full spectrum of presentations. Symptoms usually do not appear before the age of 3–5 years. Some patients develop acute or fulminant liver failure; on the other hand, many children and adults may stay clinically asymptomatic for a long time. The reason for phenotypic variability is not clear. This topic is widely discussed in Chapters 2–5. The following light microscopic pathologic findings, isolated or combined
in diverse associations, have been reported in patients with Wilson disease.
Liver steatosis In general, fatty degeneration is considered rather a frequent and, for the most part, unspecific expression of the liver parenchymal cell damage. In Wilson disease it is considered by many as one of the most typical features (Figs 7.2–7.7). The range of fatty accumulation may be wide, from mild and focal to severe, and diffuse. Types of steatosis – microvesicular vs. macrovesicular – also may vary, or frequently coexist. Interestingly, in some patients liver steatosis and inflammation in Wilson disease closely resemble nonalcoholic fatty liver disease, as seen in metabolic syndrome, or other forms of steatohepatitis. This phenomenon should be kept in mind when evaluating patients with liver disease, presenting steatohepatitis in biopsy, particularly if patients are young and not overweight.
*Correspondence to: Maciej Pronicki, Department of Pathology, The Children’s Memorial Health Institute, al. Dzieci Polskich 20, 04-730 Warsaw, Poland. Tel: +48-22-815-19-60, E-mail: [email protected]
Fig. 7.1. Liver biopsy sample of Wilson disease patient showing no substantial microscopic pathology. In some patients the liver is normal, or presents only minimal lesions in light microscopy. Portal space visible in upper right corner. Central vein at the left lower margin. Hematoxylin and eosin; original optical magnification 200 .
Fig. 7.4. Moderate mixed steatosis with features of early fibrosis. No substantial hepatitis. Hematoxylin and eosin; original optical magnification 200 .
Fig. 7.2. Mixed, predominantly pericentral steatosis of moderate degree, minimal portal inflammatory infiltrate. No fibrosis. Hematoxylin and eosin; original optical magnification 200 .
Fig. 7.5. Mild steatosis and inflammation with early, thin fibrous bridges. Hematoxylin and eosin; original optical magnification 100 .
Fig. 7.3. Moderate to severe diffuse fatty degeneration, portal space widened by lymphocytic inflammatory infiltration. No interface inflammatory activity. Hematoxylin and eosin; original optical magnification 200 .
Fig. 7.6. Severe mixed fatty degeneration with no fibrosis and no hepatitis. Hematoxylin and eosin; original optical magnification 200 .
WILSON DISEASE – LIVER PATHOLOGY
Fig. 7.7. Diffuse fatty liver with moderate fibrosis and no inflammation. Hematoxylin and eosin; original optical magnification 100 .
Fig. 7.8. Severe active inflammation with parenchymal destruction and fibrosis, steatosis. Hematoxylin and eosin; original optical magnification 200 .
Inflammation Noninfectious hepatitis of any kind and degree may be observed in Wilson disease. In terms of histologic pattern, liver involvement may attain any form of acute or chronic inflammation, including forms mimicking viral, autoimmune, or other form of hepatitis (Fig. 7.8). Inflammatory infiltrates may occupy portal spaces, sometimes with accompanying active interface hepatitis. Inflammatory cells may be also seen in intralobular areas, leading to damage and necrosis of small groups of hepatocytes (Figs 7.9 and 7.10). Both portal and lobular hepatitis may coexist in individual patients (Fig. 7.11).
Fibrosis and cirrhosis Liver fibrosis usually progresses with the development of copper deposition and consequent liver damage (Fig. 7.12). Several authors discern precirrhotic and
73
Fig. 7.9. Massive liver cell necrosis with numerous neocholangioles and diffuse scarring, with no features of liver cell regeneration (explant). Hematoxylin and eosin; original optical magnification 100 .
Fig. 7.10. High-power magnification of Fig. 7.11 (explant). Irreversible liver cell damage, neocholangioles with bile plugs, diffuse fibrosis, and inflammation. Hematoxylin and eosin; original optical magnification 400 .
cirrhotic phases of liver disease in Wilsonian patients. Initially, fibrous tissue expands portal tracts and forms thin perisinusoidal fibrous strands, then fibrous bridges develop. Later in the disease, full-blown cirrhosis may develop (Fig. 7.13). The cirrhosis in Wilson disease is usually macronodular.
Glycogenated nuclei Glycogen deposition inside the liver cell nucleus is described as one of the typical findings in Wilson disease. Glycogenated nuclei may be observed both in light and electron microscope, and are visible in periportal areas of the liver lobule (Fig. 7.14). However, this observation is highly nonspecific, also occurring in many other liver diseases.
74
M. PRONICKI
Necrosis Individual hepatocytic cell necrosis may be observed in scattered cells in many cases of Wilson disease. In rare instances of fulminant liver failure, the necrosis is massive and diffuse. In such instances, the liver cell regeneration is usually nonexistent, with diffuse neocholangiolization and fibrosis.
Ballooning degeneration
Fig. 7.11. Intralobular foci of inflammatory liver cell dropout, mixed steatosis. Hematoxylin and eosin; original optical magnification 400 .
This type of liver cell injury consists of cell enlargement with cytoplasm clearing (Fig. 7.15). It is typically observed in some types of fatty liver disease and steatohepatitis, as well as liver inflammation. Thus, ballooned hepatocytes, although seen in Wilson disease, are not specific for this disorder.
Fig. 7.12. Severe fibrosis with nodular transformation and relatively scant inflammatory infiltrate. Moderate to severe mixed steatosis. Hematoxylin and eosin; original optical magnification 200 .
Fig. 7.14. Glycogenated liver cell nuclei of ballooned and steatotic liver cells. Hematoxylin and eosin; original optical magnification 600 . The arrow shows one of the glycogenated liver cell nuclei present in the microphotograph.
Fig. 7.13. Liver cirrhosis with dispersed mild inflammatory cells; original optical magnification 100 . Periodic–acid Schiff stain with diastase digestion (explant).
Fig. 7.15. Liver cell ballooning (center) and steatosis, leading to effacement of trabecular architecture. Hematoxylin and eosin; original optical magnification 600 .
WILSON DISEASE – LIVER PATHOLOGY
Mallory bodies Mallory hyaline bodies, of the same type and morphology as classically seen in ballooned hepatocytes in alcoholic fatty liver disease and other chronic liver diseases, may be observed in Wilson disease. They consist of intracytoplasmic eosinophilic inclusions built of cytoskeletal proteins, mainly keratins. All of the above-mentioned individual histologic findings in Wilson disease may combine to form several large “biopsy patterns” (Torbenson, 2015). The most typical and well-defined are: (1) predominantly steatosis/ steatohepatitis-type damage with variable degree of fibrosis; (2) unexplained cirrhosis or hepatic fibrosis; (3) acute or fulminant hepatitis; and (4) mild, borderline pathologic lesions or even normal liver histology (Fig. 7.1).
LIGHT MICROSCOPIC DETECTION OF COPPER DEPOSITS Copper deposits in the liver are not detectable in routine sections stained with hematoxylin and eosin. In light microscopy, accumulated copper and associated proteins may be visualized by special histochemical stains. The most widely used and recognized are rhodanine and orcein. The first stain shows orange-red material accumulated in hepatocytic cytoplasm; the second stains excessive copper binding protein in brown. However, due to the focal pattern of copper accumulation in the liver, the sensitivity of the above stainings in biopsy specimens may be unsatisfactory. Moreover, copper may accumulate in liver cells in disorders other than Wilson disease, e.g., chronic cholestatic states. In the author’s experience, copper staining does not appear useful as a diagnostic tool in everyday diagnostic lab work.
ULTRASTRUCTURE Although the golden era of transmission electron microscopy in pathologic diagnostics has already passed, it should be noticed that ultrastructure of liver in Wilson disease is considered quite typical, and recognition of its pattern may appear diagnostically useful (Phillips et al., 1987). The most striking are the mitochondrial lesions. The mitochondria are enlarged, have abnormal shapes, and characteristically dilated terminal cristae
75
sometimes containing floccular deposits. Bile canaliculi show elongation of microvilli, sometimes with features of luminal obstruction, as well as “fish-mouth” outline. Other lesions include electron-dense intracytoplasmic inclusions, lysosomal copper deposits, glycogenated periportal hepatocytic nuclei, steatosis, and Mallory bodies. All of the above features may be suggestive of Wilson disease when observed together, in corresponding clinical setting. None of the described ultrastructural observations is diagnostic as an isolated finding. More about the role of liver pathology in clinical symptoms and diagnosis of WD is given in Chapters 9 and 14.
SUMMARY Since the hepatolenticular degeneration is considered a treatable disease, one message should be kept in mind: any acute or chronic liver injury of unknown origin presenting any kind and degree of histologic damage, particularly in a child or young person, should raise the suspicion of Wilson disease and prompt proper differential diagnostic action. This is particularly important when liver disease coexists with neuropsychiatric symptoms.
REFERENCES Arroyo M, Crawford J (2009). Pediatric liver disease and inherited, metabolic, and developmental disorders of the pediatric and adult liver. In: R Odze, J Goldblum (Eds.), Surgical Pathology of the GI tract, Liver, Biliary Tract and Pancreas, Saunders Elsevier, Philadelphia, pp. 1281–1283. Desmet V, Rosai J (2012). Liver, non-neoplastic diseases, tumors and tumorlike conditions. In: J Rosai (Ed.), Rosai and Ackerman’s Surgical Pathology, Mosby Elsevier, Philadelphia, PA, p. 899. Phillips M, Poucell S, Patterson J et al. (1987). The liver: an ultrastructural atlas and text of liver diseases, Raven Press, New York, pp. 255–256. Thompson R, Portmann B, Roberts E (2012). Genetic and metabolic liver disease. In: A Burt, B Portmann, L Ferrell (Eds.), Mac Sween’s Pathology of the Liver, Edinburgh, Churchill Livingstone Elsevier, pp. 203–208. Torbenson M (2015). Biopsy interpretation of the liver, Wolters Kluwer, Philadelphia, pp. 234–327.