ABSTRACT
Malignant mesothelioma is an uncommon fatal tumor that can originate from mesothelial cells of the pleura, peritoneum, pericardium, or tunica vaginalis testis. The most common type is malignant pleural mesothelioma (MPM) which often, though not always, is present as a pleural effusion. A pleural tumor probably a MPM was histologically described as early as 1970 by Wagner (1). The multipotent ability of the malignant mesothelial cells results in varied histological tumor patterns, such as epithelial, sarcomatous, or mixed (2). This causes diagnostic difficulties especially in distinguishing MPM from adenocarcinomas. Access to tissue specimens combined with immunohistochemical staining is thus shown to be of great importance in the diagnosis of MPM (3). MPM being a sarcoma would display an immunophenotype pattern that differs from adenocarcinomas. The sarcomatous origin of the tumor also results in production of extracellular matrix substances such as hyaluronan. Cytological examination of pleural fluid is less sensitive than examination of tissue specimens but can be improved with the use of electron microscopy (4).
