Malignant pleural mesothelioma (MPM) is a highly aggressive tumor that has become a very important issue over recent years (1). Asbestos exposure is the main factor involved in pathogenesis and the incidence has rised up since the 1960's. It is extimated that the incidence will reach a peak witnin the next 5 years. (1,2,3). The diagnosis of MPM is difficult because the disease may occur up to 30–40 yrs after asbestos exposure, and the differential diagnosis on pleural biopsy between MPM and pleural benign disease or metastasis of adenocarcinoma may be difficult in some cases, even with the use of immunohistochemistry