Overview

Mesothelioma is a rare cancer that begins in the lining of the internal organs of the body. Approximately three-fourths of mesotheliomas begin in the lining surrounding the lungs, called pleural mesothelioma. While pleural mesothelioma does begin in the chest cavity, it does not start in the lungs, and it is often incorrectly grouped with lung cancer. Mesothelioma that begins in the tissue surrounding the abdominal area, called peritoneal mesothelioma, accounts for about 10% to 20% of mesotheliomas. The most rare type of mesothelioma begins in the lining around a man’s testicles, called the tunica vaginalis.

There are three main types of mesothelioma:

Epithelial type. The epithelial type accounts for 50% to 70% of people diagnosed with mesothelioma. It has the best prognosis (chance of recovery) because it grows slowly and is more likely to respond to treatment.

Sarcoma type. The sarcoma type accounts for 7% to 20% of people diagnosed with mesothelioma and has a worse prognosis.

Mixed type. The mixed type accounts for 20% to 35% of people diagnosed with mesothelioma and contains both epithelial and sarcoma types. This type of mesothelioma has an intermediate prognosis.

Find out more about basic cancer terms used in this section.