Multiple Cutaneous Leiomyomas

Abstract

Cutaneous leiomyomas are uncommon tumors that arise from arrector pili muscle (pilar leiomyoma), genital smooth muscle (genital leiomyoma), or vascular smooth muscle (angioleiomyoma). Angioleiomyomas are histologically distinct, and are not known to occur as multiple lesions. Most pilar leiomyomas occur singly, but can occur as multiple lesions. As multiple lesions, they may occur in association with uterine leiomyomas and, rarely, leiomyosarcomas, in the multiple cutaneous and uterine leiomyomatosis (MCUL) syndrome. More recently, cutaneous and uterine leiomyomas have been reported to occur in association with renal cell carcinoma in the hereditary leiomyomatosis renal cell cancer (HLRCC) syndrome (1). MCUL and HLRCC likely represent part of a spectrum of one disease. These syndromes are both familial and transmitted in an autosomal dominant pattern, with variable penetrance. The implicated gene encodes fumarate hydratase, an enzyme in the Krebs cycle that maps to chromosome 1q42.3–q43 (2). Fumarate hydratase (FH) is distributed predominantly within mitochondria, but also within the cytosol, of mammalian cells.