Cerebellum, Metastatic malignant mesothelioma

Malignant mesothelioma is a rare, aggressive neoplasm of serosal surfaces closely linked to asbestos exposure. Most often a locally invasive tumour, distant metastasis can also occur. However, in most published series, intracranial metastasis is very rare, occurring in less than 3% of cases. Microscopically, mesothelioma may show a variety of morphologies, the most common being epithelioid (as in this case), spindled/sarcomatoid, or biphasic. All histologic subtypes have been reported to metastasize to the CNS, with the most common being sarcomatoid. Immunohistochemistry for mesothelial markers (e.g. WT1, calretinin) and CK5/6 helps to distinguish metastatic mesothelioma from adenocarcinoma. Prognosis of CNS mesothelioma is very poor since it often represents a late finding.