mesothelioma /mes′ōthē′lē·ō″mə/ pl. mesotheliomas, mesotheliomata [Gk, mesos + epi, above, thele, nipple, oma, tumor] , a rare malignant tumor of the mesothelium of the pleura or peritoneum, associated with exposure to asbestos. The lesion, composed of spindle cells or fibrous tissue, may form thick sheets covering the viscera. The prognosis is poor. Also called celothelioma.
