Atypical leiomyoma: An unusual variant of cutaneous pilar leiomyoma.

Cutaneous atypical leiomyoma is an unusual benign tumor arising from arrector pili muscle that shares histological features with uterine atypical or symplastic leiomyoma: atypical cellularity with pleomorphic nuclei but minimal or no mitosis. Six other cases have been reported so far and, in spite of its name and of being a smooth muscle proliferation, no recurrences nor metastasis have been reported.