A case of adrenal rest tumor of the liver: Radiological imaging and immunohistochemical study of steroidogenic enzymes.

A case of adrenal rest tumor in the liver of a 67-year-old female was reported. The tumor appeared on diagnostic imaging as a hypervascular and fat-containing mass at the periphery of right hepatic lobe and required differential diagnosis from hepatocellular carcinoma (HCC). Pathological diagnosis of the intraoperative frozen section taken under laparoscopic liver biopsy could not exclude fat-containing HCC. Therefore, she underwent partial resection of the right hepatic lobe. A yellowish-brown mass, 17 x 14 x 11 mm in a diameter, was located in the subcapsular portion. Histologically, the mass presented features similar to those of the adrenal cortex and was composed of pale cells. Immunohistochemically, the mass expressed the adrenal 4-binding protein and several enzymes involved in the synthesis of adrenocortical steroids. Based on these findings, the hepatic mass was finally diagnosed as an adrenal rest tumor of the liver.