Pleomorphic angioleiomyoma

We describe two cases of pleomorphic angioleiomyoma. In one case, a 46-year-old man presented with a single nodule on his scrotum of 1 year's duration, and in another, a 38-year-old woman presented with a single nodule on her right knee of 1 year's duration. In both cases, histopathologic examination showed a well-circumscribed nodule composed of smooth muscle and numerous veins and capillaries. Contrary to the ordinary angioleiomyoma, marked nuclear pleomorphism was noted. Although mitoses were rare, immunohistochemistry revealed many tumor cells that were positive for proliferating cell nuclear antigen, Ki-67, and p53, indicating that the pleomorphic appearance does not simply represent a degenerative change of some tumor cells.