This 59-year old woman presented with a 0.6-centimeter nodule on her left lower leg that was thought clinically to be a poroma versus a cyst versus a dermatofibroma. This is a classic presentation of angioleiomyoma in that it most commonly presents as a solitary lesion on the lower leg or feet of adult women. The lesion is usually painful. Angioleiomyoma must be distinguished from leiomyosarcoma (prominent cytologic atypia), other smooth muscle tumors such as pilar leiomyoma, and vascular anomalies. The proliferation of benign smooth muscle fibers and the way they emerge from the walls of intimately associated blood vessels in angioleiomyoma differentiate the latter from its mimics.
Higher power view demonstrates the intimate relationship of the spindle cells to the blood vessels, indicating the origin of the former from the latter. The vascular lumina are compressed.