Proliferative Marker in Distinction between Benign and Malignant Mesothelial Proliferations

Background: Differentiation of benign from malignant mesothelial proliferations is a major problem in the pathology of the serosal membranes, particularly in small biopsy specimen. This study was conducted for the evaluation of proliferative marker for distinction between malignant mesothelioma (MM) and mesothelial hyperplasia (MH). Materials and Methods: Thirty six cases of malignant mesothelioma (MM) with the mean age of 62.94 years (range: 36-80 years, M/F: 3.58) and 22 cases of mesothelial hyperplasia (MH) were evaluated for proliferative status by immunohistochemical (IHC) method with monoclonal antibody, Ki-S5 (Ki-67); the labeling indices (LI) were evaluated. Results: Average count revealed a significant increase in MM as compared with reactive MH (p value <0.0001). Considering a threshold of 9% for ki-67, a sensitivity of 88% and specificity of 94% were resulted. Conclusion: Proliferative marker of Ki-67 can be useful in distinction between malignant mesothelioma and mesothelial hyperplasia (p-value <0.0001). (Tanaffos 2006 5(2); 9-12)