[Monophasic angiomyolipoma (PEComa) of the liver]

The paper provides a morphological and immunohistochemical description of hepatic angiomyolipoma in a 29-year-old woman. Microscopically, it is a tumor with trabecular and diffuse growth patterns, which consists of polygonal cells with pleomorphic nuclei and extensive cytoplasm accumulated around the nucleus. Immunohistochemical study is of crucial importance in making the diagnosis. The tumor cells coexpress smooth muscle actin and the melanin markers: HMB-45, melan A, and MITF. The proliferative activity of the tumor is very low (Ki-67 index < 1%). According to the present views, angiomyolipoma belongs to perivascular epithelioid cell tumors (PEComas).