A hepatic lipoma mimicking angiomyolipoma of the liver: report of a case.

Lipoma of the liver is extremely rare. Since the current knowledge of such tumors is based primarily on individual case reports and small case series, little is so far known about this disease. This report presents a case of lipoma of the liver mimicking angiomyolipoma. The patient was a 38-year-old man, who was hospitalized without any symptoms after a medical check. Radiological examinations (computed tomography, ultrasonography, magnetic resonance imaging) showed a well-defined mass, which was finally diagnosed to be located in the left part of the caudate lobe of the liver, containing two spotty enhanced nodules within the tumor. These were diagnosed to be either lipoma or angiomyolipoma of the liver. The resected specimen measured 9 cm in diameter. The cut surface of the specimen showed an encapsulated, homogeneous, yellowish tumor consisting of mature adipose tissue, which was diagnosed as lipoma of the liver. The two nodules within the tumor were encapsulated hemorrhage. Histopathological examinations revealed the lipoma to be composed of mature lipocytes without angiomatous or myomatous elements. There was no immunoreactivity to homatropine methylbromide 45. Therefore, the final diagnosis was lipoma of the liver, which is an extremely rare benign liver tumor.