Atypical leiomyomas of the uterus: a clinicopathologic study of 51 cases.

Atypical leiomyoma is a well-described smooth muscle neoplasm of the uterus. Only 1 study has addressed long-term clinical follow-up in a large series, and little is known about the adequacy of treatment by myomectomy. The surgical pathology archives were searched for consecutive cases of uterine atypical leiomyoma from 1992 to 2003. Glass slides were reviewed to confirm the diagnoses, and patient age, treatment modality, and clinical follow-up data were recorded. Fifty-one atypical leiomyomas with available glass slides and clinical follow-up data were identified. Thirty tumors exhibited diffuse, moderately to severely atypical cells, whereas 21 showed atypical cells in a more focal or patchy distribution. Twelve had ischemic-type necrosis. By the highest count method, 37 cases were found to have ≤1 MF/10 HPF, 13 showed 1 to 3 MF/10 HPF, and 1 was nearly entirely necrotic precluding mitotic assessment. Among cases in which adjacent non-neoplastic tissue was well visualized, all were found to have pushing margins (46 cases). The average tumor size was 6.8 cm (median 6.5 cm; range, 0.7 to 14 cm). The average patient age was 42.5 years (median 42 y; range, 21 to 72 y). In all cases, the initial diagnostic procedure was hysterectomy (34) or myomectomy (17). Average follow-up was 42 months (range, 0.3 to 121.8 mo). Of those treated with hysterectomy, 1 had recurrent atypical leiomyoma in the retroperitoneum at 87.5 months, 1 died of other causes, and the remaining 32 (94%) were free of disease. Of the myomectomy group, 82% had no evidence of recurrent disease on follow-up: 2 had residual atypical leiomyoma in the subsequent hysterectomy specimen; and 1 underwent second myomectomy for atypical leiomyoma with 2 subsequent successful pregnancies. Atypical leiomyoma has a low rate of extrauterine, intra-abdominal recurrence (<2%) with a negligible risk for distant metastasis. Patients may be treated by myomectomy alone with successful pregnancy, but should be monitored for local intrauterine residual/recurrent disease.