Diagnostic immunohistochemistry in uterine sarcomas: a study of 397 cases.

The purpose of this study was to evaluate the use of a broad panel of antibodies used as diagnostic markers for abdominal mesenchymal tumors in uterine sarcomas. The expression of vimentin, AE1/AE3, smooth muscle actin (SMA), desmin , h-caldesmon, actin, Myf4, CD10, CD31, CD68, CD117, factor VIII, HMB-45, and S-100 protein was studied in 397 uterine sarcomas. SMA was positive in 90% of the ordinary leiomyosarcomas and when combined with desmin or h-caldesmon, a positivity of 96% and 92%, respectively, was achieved. Actin and Myf4 were positive in 4 of 5 rhabdomyosarcomas. Endometrial stromal sarcomas reacted positive with CD10 in 62 of 84 tumors and negative with h-caldesmon in 75 of 84 tumors. CD10 was the most frequent positive marker in adenosarcoma. Most tumor markers stained negative in undifferentiated uterine sarcoma, but 12 of 21 tumors reacted positive for SMA. A few focally HMB-45-positive cells were found within all tumor groups, except in rhabdomyosarcomas and giant cell tumors. Endothelial markers, S-100 protein, and CD117 do not seem to be of any diagnostic value in uterine sarcomas. In conclusion, when immunohistochemistry is used diagnostically in uterine sarcomas, a broad panel of markers provides better information than reliance on a single antibody.