Diffuse fatty metamorphosis of a large, well-differentiated hepatocellular carcinoma originating in the normal liver: a case report and literature review.

Fatty changes are frequently observed in small, well-differentiated hepatocellular carcinomas (HCCs), but are rarely observed in large (over 30 mm in diameter) lesions. Here, we report a 76-year-old man who developed a large (58 mm in diameter), well-differentiated HCC with diffuse extensive fatty changes in the right lobe of the liver. He had no history of alcohol abuse, obesity, or hepatitis B or C infection, and no autoantibodies, but he did have type 2 diabetes. The serum alpha-fetoprotein level was within the normal range, and ultrasonography showed a round hyperechoic lesion. Dynamic contrast-enhanced computed tomography revealed a tumor with inhomogeneous low attenuation in the arterial, portal, and venous phases, mimicking an angiomyolipoma. The patient underwent central bisegmentectomy of the liver, and the histological diagnosis was well-differentiated HCC with diffuse extensive fatty changes. The surrounding non-cancerous area was normal. A review of the published literature found six published cases of large, well-differentiated HCC with extensive fatty changes. Unlike the patients in most previous reports, our patient did not have any underlying liver disease and had no history of alcohol abuse.