Metastatic leiomyoma or synchronous lesion of the uteri corpus and vulva

OBJECTIVE: To reveal the morphological characteristics of simultaneously diagnosed leiomyoma of the corpus uteri and vulva. SUBJECT AND METHODS: The paper describes a case of multiple uterine leiomyomas concurrent with vulvar leiomyoma in a 39-year-old patient with progressive tumor nodule growth over 2 years. Vulvar tumor was biopsied simultaneously with extirpation of the uterus; vulvar leiomyoma was removed six months later. Histological and immunohistochemical studies: such as hematoxylin and eosin staining, the expression of smooth muscle actin, desmin, and progesterone and estrogen receptors, S100, CD10, and determination of Ki-67 proliferation index, were conducted. RESULTS: The largest (14-cm) multiple tumor nodule in the corpus uteri had the structure of leiomyoma of uncertain malignant potential; the large (8-cm) vulvar tumor was a leiomyoma with hyalinosis. The immunohistochemical profile of uterine and vulvar leiomyoma (smooth muscle actin+, desmin+, progesterone+, estrogen+ receptors, CD117-, and Ki-67) was the same (1-3%). The vulvar leiomyoma was assumed to be a tumor of metastatic origin. CONCLUSION: Vulvar leiomyoma is rare; it can arise from smooth muscle tissue of various anatomical structures of the skin and soft tissues. The pathogenesis of the so-called metastatic leiomyoma is unclear; there are concepts of a metaplastic transformation of subcelomic mesenchyme and multifocal smooth muscle proliferation. The presented case demonstrates the synchronous development of uterine and vulvar leiomyoma.