Superficial leiomyomas. A clinicopathologic study of 34 cases.

The clinicopathologic findings of 34 cases of cutaneous and subcutaneous leiomyomas were described. These were composed of 12 cases of piloleiomyoma and 22 of genital leiomyoma (scrotum, nipple and areola, vulva, and perianal region). Thirteen of 22 genital leiomyomas occurred in the vulva. Four cases of leiomyoma of pilar arrector origin had multiple lesions. The tumor occurred predominantly in adult females with an approximate sex ratio of 1:3 (8 males and 26 females). The patients with such leiomyomas ranged in age from 26 to 77 with an average of 46.8 years. The histologic feature in each case was essentially the same, and composed of interlacing bundles of smooth muscle cells, although vulvar leiomyomas frequently showed varying degrees of hyalinization and were composed of more slender tumor cells. All 12 cases submitted for immunohistochemistry showed a strongly positive staining both for actin and for desmin. In our view, cutaneous and subcutaneous leiomyomas, excluding angioleiomyomas, are undoubtedly rare in occurrence.