Metastatic low-grade endometrial stromal sarcoma of clitoris: report of a case.

Low-grade endometrial stromal sarcoma (ESS) is an uncommon neoplasm, which has a highly recurrent nature. A review of the literature revealed that only one case of low-grade ESS, arising within the vulva from a focus of endometriosis, has been previously published. We describe an additional case of low-grade ESS arising within the vulva and to the best of our knowledge the first report of low-grade ESS metastasized to clitoris. A 46-year-old woman was admitted to our hospital due to a heavy uterine bleeding. A physical examination revealed a lesion in clitoris, which exhibited a densely cellular mesenchymal neoplasm on microscopy. On the basis of the pathologic features alone, a differential diagnosis of a low-grade ESS and cellular leiomyoma was considered. Seven months later, the patient presented again with excessive uterine bleeding and a total hysterectomy was performed. A tumor of white-tan, whorled appearance was found. Its features were suggestive of low-grade ESS. Taking into account the possible extrauterine location of an ESS and reviewing the first case, a diagnosis of rare low-grade ESS metastasized to clitoris was made.