Rhabdoid Epithelioid Leiomyosarcoma of the Uterine Corpus

Abstract

A case of epithelioid leiomyosarcoma of the uterus with rhabdoid phenotype and early rhabdomyoblastic differentiation is described. A 72-year-old woman with a 5eek history of increased abdominal girth was found to have a large pelvic mass. The uterus revealed a large intramyometrial and left adnexal necrotic tumor that had spread to the small bowel mesentery and to the anterior abdominal peritoneum. The tumor was an epithelioid leiomyosarcoma with rhabdoid phenotype and focal early rhabdomyoblastic differentiation, as confirmed by immunohistochemical and ultratructural techniques. Also called composite extrarenal rhabdoid tumor (CERT), this lesion should be differentiated from malignant mixed mullerian tumor, rhabomyosarcoma, endometrial stromal sarcoma, and pure rhabdoid tumors of the uterus. The recognition of a rhabdoid phenotype is of clinical importance since these tumors are prone to be aggressive.