90% of primary liver neoplasms are hepatocellular carcinomas.
Most common in the mid to late decades of life.
More common in men than women (3/4:1).
Patient may have history of hepatitis B or C viral infections, alocohlic cirrhosis, primary hemochromatosis, tyrosinemia, or consumption of carcinogens (aflatoxin B₁, from aspergilus or thorotrast).
May present as hepatomegaly or weight loss.
The serum level of alpha-fetoprotein may be elevated.
Grossly appears as a single or multiple, white-gray to yellow masses. The tumor may be bile stained.
Microscopically the well differentiated tumor consists of hepatocytes arranged in trabecular (sinusoidal) or acinar (tubular) structures. The poorly differentiated tumor consists of poorly differentiated cells sometimes forming giant cells. The pathognomonic feature is formation of bile or bile canaliculi which may be visualized at the ultrastructural level. The tumor cells stain positive for low molecular weight cytokertain (CAM 5.2), alpha fetoprotein, and alpha₁ anti-trypsin.