[A Resected Case of Angiomyolipoma Difficult to Be Distinguished from Hepatocellular Carcinoma]

A 42-year-old man complaining of left back pain was admitted to our hospital. The hepatis B and C surface antigens were negative. The serum levels of tumor markers were within the reference ranges. Abdominal ultrasound revealed an 8 cm-sized, primarily round and hyperechoic mass in the left lateral segment. Contrast-echo showed non-uniform enhancement in the arterial phase and uniform enhancement in the portal phase. This mass did not indicate"wash-out"on contrast- enhanced CT. It showed hypointensity in the hepatobiliary phase on MRI. The definitive diagnosis could not be obtained, and the patient was suspected with malignancy, such as hepatocellular carcinoma(HCC). Therefore, left hemi-hepatectomy was performed for the diagnostic treatment. Based on the immunochemical staining results, he was diagnosed with angiomyolipoma( AML). AML is composed of fat, blood vessels, and smooth muscles. It is regarded as a tumor of perivascular epithelioid cell tumor(PEComa). Early venous return and adipose tissues in the tumor were the distinctive features of this tumor. The preoperative diagnosis of AML without any fatty component as in this case is very difficult.