Types of Malignant Mesothelioma

Malignant mesothelioma can be classified according to where the cancer develops. The two most common types of malignant mesothelioma are pleural and peritoneal.

Malignant Pleural Mesothelioma

Most people diagnosed with malignant mesothelioma have cancer in the pleura, the lining of the lungs and chest cavity.

This aggressive cancer causes the pleura to thicken, preventing the lungs and chest from expanding normally. As a result, fluid may accumulate in the chest cavity. People with malignant pleural mesothelioma often develop shortness of breath, a dry cough, and chest pain.

An X-ray typically reveals fluid in the chest. Many doctors may suspect pneumonia or another inflammatory condition, and they don’t immediately inquire about asbestos exposure. This delays the diagnosis.

Malignant Peritoneal Mesothelioma

Mesothelioma may also arise from the lining of the abdomen. This type of cancer develops in the peritoneum, the thin membrane that surrounds the abdominal cavity and the surface of the abdominal organs.

Some doctors believe that a person may contract this condition by ingesting asbestos fibers, which become trapped in the peritoneum. Inhaled asbestos fibers can also reach the peritoneum through the lymphatic system, a series of vessels that drain fluid from the body’s organs. Sometimes, malignant pleural mesothelioma metastasizes, or spreads, from the lungs to the abdominal cavity.

Symptoms may include abdominal pain and swelling, nausea, and vomiting.

Cell Types of Mesothelioma

Malignant mesothelioma can also be described by cell type. There are three primary types.

Epithelial mesothelioma, which is named for its sheet-like epithelial cells, comprises more than 50 percent of all mesotheliomas. This cell type tends to respond better to treatment than others.

Sarcomatoid mesothelioma is known for its “spindly” cells; it comprises between 10 and 20 percent of all mesotheliomas. This type is usually aggressive, meaning it grows and spreads quickly.

The biphasic type features a mixture of the two cells. It comprises between 30 and 40 percent of all mesotheliomas. The aggressiveness of this type of mesothelioma depends on the ratio of epithelial to sarcomatoid cells. The more epithelial cells there are, the more likely the cancer is likely to respond to treatment.