Papillary mesothelioma, also known as well-differentiated papillary mesothelioma (WDPM), is an uncommon variation of epithelioma mesothelioma. It is frequently diagnosed in women, generally those who are still in the reproductive stages of their life, but it has also been clinically diagnosed in men as well.

The disease usually develops in the peritoneum - the lining of the abdomen - and, in most cases, is benign. Papillary mesothelioma, however, has also been seen to have origins in the tunica vaginalis, part of the male reproductive system as well as in the pleura or the lining of the lungs.

Papillary mesothelioma tumors generally cause no pain and the mesothelioma prognosis for someone diagnosed with such a tumor is usually very favorable. Unlike malignant mesothelioma of various types, however, this kind of mesothelioma cannot be definitively linked to asbestos exposure though a connection has been made in some cases.

Because the occurrence of this disease is quite rare, there is no standard mesothelioma treatment at this time. Past reports have shown that mesothelioma doctors who do encounter WDPM have offered surgical removal of the tumor as a possible treatment and others have shrunk the tumor with mesothelioma chemotherapy or radiation. However, it is rare that this kind of tumor spreads to other parts of the body, so mesothelioma surgery is usually the preferred option. Reoccurrence of the disease does happen in many cases but is not an indication that the patient will later develop a malignant form of mesothelioma cancer.