Lipid-rich clear-cell hepatocellular carcinoma arising in non-alcoholic steatohepatitis in a patient with diabetes mellitus.

A case of lipid-rich clear-cell hepatocellular carcinoma arising in non-alcoholic steatohepatitis is described in a patient with diabetes mellitus. The patient was a 67 year-old Japanese female with a history of tuberculosis, appendicitis, ischaemic heart disease, and non-insulin-dependent diabetes mellitus. The patient denied alcohol consumption. A liver mass was diagnosed as hepatocellular carcinoma of clear-cell type with early cirrhosis of the peri-tumoral liver tissue. Tumour cells had clear cytoplasm containing lipid droplets, and Mallory bodies. Surrounding non-tumoral liver tissue also showed lipid, and fibrosis in peri-portal areas with moderate bridging fibrosis. The features were consistent with clear-cell hepatocellular carcinoma arising in the fibrosis of non-alcoholic steatohepatitis. By electron microscopy, tumour cells had lipid droplets, glycogen, swollen mitochondria, rough endoplasmic reticulum, Mallory bodies, small bile canaliculi, desmosomes and gap junctions. Surrounding non-tumoral hepatocytes had a largely normal ultrastructure with prominent glycogen and lipid droplets. Clear-cell hepatocellular carcinoma within non-alcoholic steatohepatitis associated with diabetes mellitus is an extremely rare condition, and this report provides a detailed histopathological description with both immunohistochemical and ultrastructural data.