Histologic examination revealed a dermal tumor composed of bundles of spindle cells with eosinophilic cytoplasm and long nuclei. Cellular pleomorphism and mitotic figures were not seen. The tumor bundles appeared red with a trichrome stain.
Cutaneous leiomyomas are rare, benign, but painful tumors of smooth muscle origin. There are 4 types of leiomyomas of the skin: (1) solitary piloleiomyomas arising from the arrectores pilorum muscle; (2) multiple piloleiomyomas arising from arrectores pilorum muscles; (3) solitary genital leiomyomas arising from dartoic, vulvar, or mammillary muscle; and (4) solitary angioleiomyomas arising from the muscle of veins.1