Problematic Uterine Smooth Muscle Neoplasms

A recent trend in the classification of uterine smooth muscle neoplasms (USMNs) into clinically benign and clinically malignant groups has been to move from exclusive reliance upon mitotic index (MI) to an approach that incorporates additional histopathologic characteristics. In furtherance of this goal, we assessed a variety of histopathologic features of 213 problematic smooth muscle neoplasms for which we had > or = 2 years of clinical follow-up data or for which there was an unfavorable outcome. One hundred and thirteen of these patients have had a minimum follow-up of 5 years, and 48 have been followed for > or = 10 years. Cases eliminated from the study group included USMNs with a significant myxoid or epithelioid component and cases of intravenous leiomyomatosis. USMNs, whether cellular or not, with no cytologic atypia and with a mitotic index (MI = number of mitotic figures mf/10 high-power fields hpf) of or = 10 mf/10 hpf, four of 10 failed.(ABSTRACT TRUNCATED AT 400 WORDS)