Localized Intrasplenic Mesothelioma

Malignant mesothelioma is a primary neoplasm of the serosal membranes that usually presents with a diffuse pattern of growth. However, cases of localized mesotheliomas have been described. The predominant localization is the pleura; peritoneum and pericardium being rarer localizations. Only few cases of true intraparenchymal mesothelioma arising in organs such as liver, gonads, lung, and pancreas have been described. We report a case of an otherwise healthy 48-year-old man without asbestos exposure with a nodule of 3 cm in diameter, localized in the spleen, discovered incidentally at the ultrasonographic examination, for which histopathological and immunohistochemical findings were consistent with epithelioid mesothelioma: large round cells with eosinophil dense cytoplasm and macronucleoli and with immunohistochemical positivity for pancytokeratins, calretinin, Wilms tumor-1, and others markers of mesothelial differentiation. The diagnosis of localized intrasplenic epithelioid malignant mesothelioma was carried out. To the best of our knowledge, this is the first case of a localized intrasplenic mesothelioma published in the indexed literature.