MONDO_0006364 (peritoneal well differentiated papillary mesothelioma) is a localized or multifocal mesothelioma arising from the peritoneum. It predominantly occurs in women. It is characterized by the formation of papillae, covered by a single layer of blunt mesothelial cells. Mitotic figures are not present. There is no evidence of severe cytologic atypia. It has a relatively favorable clinical outcome, compared to diffuse malignant mesothelioma. Also known as: peritoneal WDPM.