Abstract

Angiomyolipoma is the most common mesenchymal tumor of the kidney. It occurs sporadically and is associated with tuberous sclerosis. It can appear in any organs, but most commonly in the kidney, and it appears slightly more in females. Angiomyolipoma is pathologically composed of three heterogeneous components of blood vessels, smooth muscle cells and fat cells of varying proportion, which occasionally make several unusual histologic variants. We describe a variant of renal angiomyolipoma simulating vascular leiomyoma on routine hematoxylin-eosin stain; prominent thick-walled blood vessels interspersed with proliferation of smooth muscle cells and total absence of fat cells. Perivascular spindle-shaped smooth muscle cells were reactive for smooth muscle actin, desmin and HMB-45 immunostains. This case illustrates vascular leiomyoma-like angiomyolipoma, which was finally diagnosed on the basis of HMB-45 immunostain, and also raises a question about the real existence of renal vascular leiomyoma.

• Keywords: Angiomyolipoma;Amgiomyoma;Kidney Neoplasms