A hepatic angiomyolipoma with rapid growth after a follow-up period of thirteen years

The case presented here is a 63-year-old woman. A liver tumor 76 mm in diameter was detected and diagnosed as hepatic angiomyolipoma. Although there was no change in the size and shape of the tumor from November 2000 to March 2014, it had grown to 126 mm by September 2014. The patient was admitted to our hospital in November for tumor evaluation, and the tumor was 140 mm in size by December 2014. Right hepatectomy was performed. The resected specimen was 1,230 g in weight and 150 mm in size, with a massive hematoma in the tumor. Gross inspection of the resected specimen showed a dark brown mass with light brown hard tissue accompanied by adipose tissue in the right lobe of the liver. Pathological examination showed proliferating smooth muscle cells that were positive for both HMB45 and a-SMA on immunohistochemical studies and adipose cells similar to a lipoma. The tumor was diagnosed as hepatic angiomyolipoma. The greater part of the tumor consisted of hematoma and necrosis, and hemorrhage leading to necrosis was considered the cause of the rapid tumor growth. Continuous follow-up is necessary for patients with hepatic angiomyolipoma without change in size for a long period.