Difficulties of differential diagnosis between atypical leiomyoma and leiomyosarcoma of the uterine body

Leiomyoma of the uterus is a benign hormone-dependent tumors in women.The incidence of LM among gynecological diseases is 25 to 50%, according to different authors. In reproductive-aged women its frequency is about 30%. WHO recommends to allocate leiomyoma, which in russian literature often referred to as a simple or ordinary leiomyoma, and its histologic variants (cellular, mitotic activity, epithelioid, myxoid, atypical leiomyoma and lipoleyomioma etc.).We performed clinical and morphological analysis of atypical uterine leiomyoma in 44-year-old woman. Immunohistochemical study detected positive reaction to smooth muscle actin, dismin, progesterone receptors, N-caldesmon. Adverse reactions to c-kit, ER keratins. Proliferation index by Ki-67 does not exceed 10%. At the molecular genetic research in the studied loci, the microsatellite instability and loss of heterozygosity, characteristic of the LMS, were not revealed.