[Smooth muscle neoplasms of the uterus--a 51 cases study].

To discuss the diagnosis of uterine leiomyosarcoma and leiomyoma of cellular and bizarre type, we reviewed 51 cases and carried out P53 and desmin immunohistochemical staining on 43 cases. We found that in most cases leiomyosarcoma is accompanied by nuclear mitosis, cell atypia and margin infiltration. In a small number of cases, though mitotic figures are scarce, high cell atypia and marked margin infiltration were present. Leiomyoma variants may have high cellular density and bizarre nuclears but have no margin infiltration. Leiomyosarcoma has a high incidence of P53 expression, while no P53 expression was detected in leiomyoma variants. Desmin expression is closely correlated with the differentiation of smooth muscle neoplasms of the uterus. We conclude that nuclear mitotic activity is an important but not independent criteria in the diagnosis of uterine leiomyosarcoma. Cellular atypia and margin infiltration should be considered. P53 and desmin expression can be applied as accessary criteria.