Cluster of uterine mullerian adenosarcoma in the Washington, DC metropolitan area with high incidence of sarcomatous overgrowth.

Mullerian adenosarcoma is an uncommon variant of uterine sarcoma. Twelve uterine adenosarcomas were diagnosed during a 42-month period at the Washington Hospital Center in Washington, DC. Based on estimated incidence data derived from the US Department of Defense beneficiary population, an estimated relative risk of 15.4 (95% confidence interval, 7.7-31.0) was calculated, indicating a significantly increased incidence of adenosarcoma in the population studied (p<0.0000001). Among 10 patients who underwent hysterectomy, six (60%) of their tumors had sarcomatous overgrowth. In comparison with the previously reported proportion of adenosarcomas with sarcomatous overgrowth, approximately 16%, the proportion with sarcomatous overgrowth was significantly higher than expected (p<0.01). Mullerian adenosarcoma with sarcomatous overgrowth was first described in 1989 and suggests that the cluster of adenosarcomas reported herein may be due in part to the current classification of some uterine tumors as adenosarcoma with sarcomatous overgrowth that previously would have been classified as other types of uterine sarcoma. Nonetheless, even after reviewing and updating the classification of all sarcomas diagnosed at the Washington Hospital Center from 1985 to 1998, the ratio of adenosarcomas to uterine adenocarcinomas during the 1994-1998 period was 4.7 times (p<0.005) that of the 1985-1993 period, suggesting a more modest but real increase in the occurrence of this tumor. Correct classification of mullerian adenosarcomas with sarcomatous overgrowth is important because the limited available data suggest that the prognosis is notably worse than that for adenosarcomas without sarcomatous overgrowth.