Clinical and pathological features of 41 homologous uterine stromal tumors classified by the criteria of Norris and Taylor were reviewed. These included stromal nodules (12 cases), endolymphatic stromal myosis (20 cases), and stromal sarcoma (nine cases). Patients ranged in age from 18 to 79 with a median of 45 years. Symptoms were similar in all three forms and included vaginal bleeding (63%), pelvic pain (11%), or an abdominal mass (6%), while 26% of patients were asymptomatic. Tumors characteristically resembled endometrial stroma histologically, but variations included hemangiopericytoma and "sex-cord-like" patterns, hyalinization, and foam cells. A sex-cord-like pattern was seen only with stromal nodules and endolymphatic stromal myosis. Necrosis was seen in all three lesions, whereas nuclear anaplasia was seen only with stromal sarcoma. Follow-up ranging from 2 months to 12 years (median interval: 5 years) was obtained in 23 cases. No recurrences were recorded among six stromal nodules. Endolymphatic stromal myosis behaved as an indolent low grade malignancy, with three recurrences but no deaths among 13 patients; these occurred at 3 to 7 years after initial diagnosis. Stromal sarcoma behaved as a high grade malignancy, with two deaths among five patients with follow-up, both occurring within 8 months of diagnosis.