A benign proliferative neoplasm made up of epithelial and mesenchymal cells of the mesothelium which make up part of the serosal covering and lining of various organ surfaces within the body. The disease is MONDO_0002373 (benign mesothelioma). Also known as: benign tumor of mesothelial tissue, benign tumor of mesothelium, benign tumour of mesothelial tissue, benign tumour of mesothelium, mesothelioma, benign.