Pelioid-type well-differentiated hepatocellular carcinoma in a patient with a history of taking oral contraceptives: report of a case.

We report a case of pelioid-type well-differentiated hepatocellular carcinoma (HCC) in a 54-year-old woman with a history of taking oral contraceptives. She was not infected with hepatitis viruses and her liver function test results were normal. Contrast-enhanced computed tomography showed an irregular-shaped and remarkably enhanced tumor with central necrosis. The tumor was vaguely nodular without capsules, and consisted of multiple pelioid cysts and sinusoidal dilatations with transitional forms between them. The pelioid cysts were directly surrounded by neoplastic cells with fatty degeneration. Since pelioid-type HCC has similar radiological and pathological features to peliosis hepatis, it is difficult to differentiate them based on drug history and imaging studies. The detection of stromal invasion into the portal area is necessary to distinguish well-differentiated HCC from benign hepatic tumors.