Malignant mesotheliomas are derivated from mesothelial tissue or serosa. They may originate from the pleura, periotoneum, pericardium, and other miscellaneous serosal surfaces. Mesotheliomas are relatively rare and are clearly related to exposure to asbestos. Asbestos is widely used for industrial purposes and most of these patients have had occupational exposure. An unusual variety of this pathology is the mesothelioma with deciduoid morphology not associated with the exposure to asbestos. There are very rare the patients reported with this variety of peritoneal mesothelioma. The diagnosis of mesothelioma may be difficult to determine preoperatively. A patient with this pathology is reported and the clinical features laboratory findings and the therpay performed, are detailed in the article