CLINICAL HISTORY
A 37-year-old previously healthy woman, presented with a five-month history of weight loss anorexia, abdominal distention and discomfort. The patient had no prior history of hepato-biliary disease or tuberous sclerosis. Physical examination disclosed hepatomegaly with a liver span equal to 20 cm (Figure 1 A). On palpation of the abdomen, there was a renitent firm mass in the upper right quadrant mobile with respect to the superficial planes and fixed with respect to the deep planes. Tumor markers, including alpha-fetoprotein, carcinoembryonic antigen, and carbohydrate antigen 19-9 were all within normal limits. Aspartate aminotransferase, alanine aminotransferase and total bilirubin were within the normal range. Contrast-enhanced computed tomography scan demonstrated a hepatic mass located in segments IV, V and VI, with exophytic development, moderate and heterogeneous arterial enhancement, continuing in the portal and late stages, without detectable washout or late capsular enhancement (Figures 1B & 1C). This mass measured 170 x 110 mm in the axial plane and 200 mm in height. It had a close vascular contact with the right hepatic artery, the cystic artery, the right portal branch as well as its segmental portal branches of IV and VI, which remained permeable, without real invasion. Computed tomography scan also disclosed a left ovarian mass measuring 90 x 60 x 90 mm suggestive of teratoma (Figure 1C). On abdominal magnetic resonance imaging (MRI), low intensity was observed on a T1-weighted image and high intensity on a T2-weighted image. The patient underwent fine needle biopsy of the hepatic mass and histopathological examination of the biopsy specimen was suggestive of hepatocellular carcinoma. Right hepatectomy was performed with informed consent of the patient. Intraoperatively, a relatively soft dark red giant tumor was found to occupy the whole right lobe of the liver (Figure 1D). We received a hepatectomy specimen which weighed 1050 grams and measured after formalin fixation 17 × 15.5 × 6.5 cm. Cut section showed a well-circumscribed cystic mass measuring 16 cm in diameter with a hemorrhagic appearance and focal grey white firm areas in the periphery (Figure 2A). Histologically, the mass was composed of an admixture of smooth muscle cells, adipose tissue, and blood vessels (Figure 2B). Sheets of mature adipocytes were seen in some of the sections focally. The tumor proliferation consisted of 100% of epithelioid cells arranged in a trabecular pattern (Figure 2C) or in sheets. Extensive extramedullary hematopoiesis was noted in several sections with hematopoietic elements, including megakaryocytes as well as erythroid and myeloid precursors (Figure 2D). The vascular component was abundant and was composed of thick (Figure 2B) and thin-walled vessels with a striking peliotic pattern in some areas (Figure 3A). The epithelioid cells showed round nuclei, and abundant eosinophilic or clear cytoplasm (Figure 3B). Brown melanin granules were focally found within the tumor (Figure 3 C). Neither tumor necrosis nor mitotic figures were observed. The nonneoplastic liver showed mild nonspecific mononuclear infiltration in the portal tracts. Based on these microscopic findings, epithelioid angoimyolipoma, epithelioid hemangioendothelioma, hepatocellular carcinoma and hepatocellular adenoma were considered as differential diagnoses and an immunohistochemical study was performed. HMB45 (Figure 3D), MelanA, Smooth Muscle Actin and Desmin showed diffuse strong positive staining. However, the tumor cells showed negative staining for anti-hepatocyte, and CD34. The postoperative course was uneventful, and the patient was discharged on postoperative day 10. At present, she is still being followed-up.