A scoring system for histopathologic and immunohistochemical evaluations of uterine leiomyosarcomas

Uterine leiomyosarcomas (LMS) are difficult to distinguish from benign leiomyomas without surgery. In this study we performed transcervical needle biopsy on 475 patients, 8 LMS patients and 467 patients with non-sarcomas (non-LMS) in a high-risk group for LMS, and evaluated whether examinations performed with Ki-67 and CD34 immunohistochemical analyses in addition to the standard hematoxylin-eosin (H&E)-stained sections would improve preoperative diagnostic precision of the uterine smooth muscle tumors. Histopathologic analysis included three factors: degree of cytologic atypia, mitotic index and coagulative tumor cell necrosis (CTCN). We also evaluated cell proliferation with Ki-67 expression. In cases of suspected CTCN, we examined CD34 expression and counted positive blood vessels in the necrotic area. Three of the 8 LMS cases satisfied the diagnostic criteria of LMS by histopathologic evaluation with H&E-stained sections. We made a score list based on these analyses; scores for LMS specimens ranged from 6-14 points; non-LMS specimens scored 0-2 points. At the cut-off score of 6 points, the positive predictive value to distinguish LMS from non-LMS was 100%, showing that this scoring system, is a useful method for preoperative differentiation between LMS and non-LMS tumors.