Two Cases of Hepatic Angiomyolipoma with Radiologic Similarity to Hepatocellular Carcinoma

Hepatic angiomyolipoma (AML), a rare benign mesenchymal tumor, is composed of fatty tissue, proliferated blood vessels, and smooth muscle cells. Since the proportion of this three components is variable, radiologic and pathologic findings of the tumor can show different features, which makes its diagnosis difficult. On ultrasonography, it is usually a well defined hyperechoic mass and has occasional posterior enhancement of echoes as seen in hemangioma. On dynamic enhancement study, it shows not only prominent enhancement on the arterial-dominant phase and gradual hypoattenuation on the delayed phase, but also gradual and prolonged enhancement, and thus, it can be misdiagnosed as hepatocellular carcinoma or hemangioma. Positive reactivity for HMB-45, melanoma-specific antibody, makes the diagnosis possible and reactivity for smooth muscle actin confirms the diagnosis. We report two cases of hepatic AMLs, which were initially thought to be hepatocellular carcinomas because of early enhancement of the arterial phase and gradual hypoattenuation of the delayed phase on dynamic study of CT or MRI. One case was treated by chemoembolization of hepatic artery followed by hepatic resection, and the other was treated by hepatic resection after gun biopsy under ultrasound guidance. (Kor J Gastroenterol 2000;36:424 - 430)ope