Expression of ki-67 in uterine smooth muscle tumors as a predictor of proliferative activity

Context: Uterine smooth muscle tumors comprise of benign leiomyomas, benign variants of leiomyomas, borderline neoplasms and malignant leiomyosarcomas. Accurate categorization of these tumors by light microscopy can be challenging, particularly the distinction of leiomyosarcomas from certain benign variants and tumors of uncertain malignant potential.
Objective: The aim of the current study was to evaluate the expression of Ki-67 in uterine smooth muscle tumors, comparing leiomyomas, leiomyoma variants and leiomyosarcomas (LMS) and to prove the accuracy of ki-67 expression as a useful parameter in the diagnosis of these neoplasms.
Study design: In our study, we analysed 230 cases of uterine smooth muscle tumors histopathologically and 50 cases were selected for assessment of ki-67 expression, using immunohistochemistry. Ki-67 expression was then correlated with the histopathological diagnosis.
Results: Our results demonstrated that there was significantly elevated ki-67 expression in leiomyosarcomas, which correlates well with the rapid growth of these malignant tumors, significantly low ki-67 expression in usual leiomyomas and intermediate level of expression in certain histopathologically benign variants.
Conclusion: Ki-67 may be a useful immunohistochemical parameter to distinguish between cases of malignant smooth muscle tumors from those with borderline histology or certain variants, with special concern towards their biological behavior.