Hepatocellular adenoma containing hepatocellular carcinoma in a male patient with familial adenomatous polyposis coli: Report of a case

Hepatocellular adenoma (HCA) is a benign condition occurring most frequently in young women using oral contraceptives. We herein report the first case of a 28-year-old man with familial adenomatous polyposis (FAP) who experienced hepatocellular carcinoma (HCC) within HCA. A preoperative computed tomography scan of the abdomen disclosed a tumor measuring 5.8 cm in diameter in the left lobe of the liver. A total proctocolectomy with construction of a linear stapled J-pouch, a hand-sewn ileoanal anastomosis and a liver tumor resection were performed. The pathology of the resected specimen confirmed the diagnosis of HCA containing HCC. Five cases of HCA have been reported that developed in patients with FAP, but this is the first case of HCA containing HCC. Hepatocellular adenomas occur due to the inactivation of hepatic nuclear factor 1α, but the mechanism underlying the malignant transformation from HCA to HCC could not be identified in this case.