Immunohistochemical analysis in the diagnosis of uterine myometrial smooth muscle tumors.

Uterine myometrial smooth muscle tumors sometimes raise concerns related to their histopathological typing, and that especially for benign entities with areas of atypia. In this study, we analyzed a group of myometrial smooth muscle tumors in what it regards their differential diagnosis utilizing a panel of antibodies consisting of α-SMA, Ki-67, p16, p53, PR and bcl-2. The study included a total of 16 cases of cellular leiomyomas, five cases of atypical leiomyomas and six of leiomyosarcomas, which were all analyzed for age, risk factors, mitotic activity, cellular atypia and tumor staging. In cases of cellular leiomyomas, the immunophenotype was characterized by high expression of PR and bcl-2 and low expression of p53 and Ki-67. For atypical leiomyomas, PR, bcl-2 and p53 expression levels were highly compared with low levels of p16 and Ki-67. Leiomyosarcomas immunophenotype was characterized by high expression values of Ki-67, p16 and p53, and decreased levels of PR and bcl-2. The study indicated specific immunophenotypes among the uterine myometrial smooth muscle tumors analyzed. The antibody panel used here might be a useful for the complementary histopathological analysis of myometrial leiomyomas and leiomyosarcomas.