Lipoleiomyomatous tumors of the uterus: a heterogeneous group? Histopathological study of five cases.

Five surgical cases of lipoleiomyomatous tumor of the uterus were studied histopathologically. All the patients were postmenopausal. Three tumors had arisen in the corpus, and the remaining two in the cervix. In four of five cases, tumors consisted of smooth muscle tissue admixed with varying amounts of mature adipose tissue, which did not show cytological atypism. In the remaining single case, the tumor contained, in addition to smooth muscle tissue and fibroadipose tissue, many anomalous arterial blood vessels, which showed an irregular, tortuous appearance resembling that found in renal angiomyolipoma. From the histopathological findings and a review of the relevant literature, it was considered that lipoleiomyomatous tumor of the uterus is not a single histopathological entity but is composed of two distinct neoplasms with different histogenesis; that is, 'lipoleiomyoma' and 'anglolipoleiomyoma'. While the latter tumor is most likely of a choristomatous nature, the former probably arises from 'lipomatous' metaplasia of a pre-existing leiomyoma.