Huge Hepatic Angiomyolipoma Mimicking Low Grade Hepatocellular Carcinoma

A 41-year-old man was diagnosed with a huge symptomatic liver mass and was referred to our hospital for liver biopsy and further evaluation. He presented with right upper quadrant tenderness. Enhanced abdominal computed tomography and magnetic resonance imaging revealed a 12.5-cm relatively well-defined heterogeneous enhancing mass in the right inferior liver with a large exophytic component containing a fat component and progressive delayed enhancement. The patient underwent right inferior sectionectomy. The pathological diagnosis was confirmed as angiomyolipoma, 12.3×9.2×5.0 cm in size, with tumor necrosis in 20% of the tissue. Hepatic angiomyolipoma is known as a benign tumor, but in our case, because of the large tumor size and coagulative necrosis, this tumor had malignant potential; surgical resection was deemed to be appropriate, and close follow-up monitoring was essential postoperatively.