Unusual hepatic tumor with features of mesenchymal hamartoma and congenital solitary nonparasitic cyst.

We report a hepatic tumor in an adolescent that does not fit into any of the described categories of liver tumors. The patient presented with hepatomegaly, abdominal pain, and normal liver function test; the tumor was cystic in imaging studies. The resected specimen, result of a partial hepatectomy, measured 21 cm and was multicystic with solid areas. Microscopically, the cysts were lined by a mucous-producing or intestinal-type epithelium, associated with smooth muscle and small mucous-producing glands. The solid component contained fibrous and adipose tissue, smooth muscle and thick-walled vessels. Aneuploidy was demonstrated by flow cytometry. We interpreted the tumor as having features of a mesenchymal hamartoma and congenital solitary nonparasitic cyst. It is conceivable that the lesions originated with small peribiliary glands with dilatation and intestinal metaplasia.

Atypical morphologic presentation of biliary atresia and value of serial liver biopsies.

BACKGROUND: Liver biopsy findings are important in diagnosing extrahepatic biliary atresia. Diffuse ductular proliferation is a characteristic finding. We describe four patients with conjugated hyperbilirubinemia in whom the initial liver biopsy findings showed a lack of ductular proliferation, despite subsequent development of biliary atresia. RESULTS: On initial biopsy, paucity of intrahepatic bile ducts was present in three of four patients, with a bile duct to portal space ratio of 0.3 to 0.4 (normal, 0.9-1.8). A normal bile duct to portal space ratio of 1.0 was observed in the fourth patient. Ductular proliferation became apparent in three subjects between 9 and 12 weeks of age, and biliary atresia was noted at the time of a Kasai portoenterostomy. The fourth child had well-developed biliary cirrhosis at liver transplantation. CONCLUSIONS: Changes characteristic of biliary atresia may appear even after 9 weeks of age. Bile duct paucity and normal bile duct to portal space ratio do not preclude the subsequent development of biliary atresia. Infants with unexplained conjugated hyperbilirubinemia and acholic stools should undergo sequential liver biopsies until clinical improvement occurs or until biliary atresia can be excluded from the differential diagnosis.