Cutaneous leiomyoma with cytologic atypia, akin to uterine symplastic leiomyoma.

ABSTRACT

BACKGROUND: Smooth muscle tumors of the skin with cytologic pleomorphism and mitotic activity have traditionally been characterized as leiomyosarcomas, despite having a benign clinical course. In the uterus, there is a smooth muscle tumor known as symplastic leiomyoma, which typically has cytologic pleomorphism without significant mitotic activity. OBJECTIVE: The objective was to illustrate by case report the unusual histologic variant of the cutaneous pilar leiomyoma analogous to the symplastic leiomyoma of the uterus. METHODS: A 54-year-old woman presented with a clinical picture of cutaneous leiomyoma but had histologic features of nuclear hyperchromasia and pleomorphism, but rare mitoses. RESULTS: Management of this patient included excision of the involved area. CONCLUSION: Symplastic leiomyoma is an atypical uterine leiomyoma with cytologic atypia. We present the case of a patient with cutaneous leiomyomas that histologically demonstrated similar features to a uterine symplastic leiomyoma. We believe that this represents a distinct histologic variant of the cutaneous pilar leiomyoma analogous to the symplastic leiomyoma of the uterus.