Diagnostic value of mitotic activity in endometrial stromal sarcoma: report of two cases.

Two patients with endometrial stromal neoplasms, one low-grade and one high-grade malignant stromal sarcomas, were treated. The tumor cells of these two sarcomas had many common cytologic features and were similar to normal endometrial stromal cells. However, frequent mitoses were characteristic of the cytologic specimens of the high-grade stromal sarcoma but not of those of the low-grade sarcoma. Mitotic activity thus appears to offer a clear distinction in the cytologic differentiation between grades of endometrial stromal sarcoma and may serve as a guide to prognosis and treatment.