Types of Mesothelioma

All types affect mesothelial structures

Mesothelioma is a relatively rare form of cancer, diagnosed in 3,000 people in the United States each year.  What all types of mesothelioma have in common is their location in the mesothelial membranes of the body. The mesothelial membranes are the thin and clinging tissues that line the chest, abdominal cavities, and outer surface of most internal organs.  The mesothelium produces a lubricating fluid that helps organs by enabling them to move.  The different types of mesothelioma refer to where the cancer is located.

Pleural mesothelioma

The most frequently occurring form is pleural mesothelioma, found in the outer lining of the lungs.  There are two layers of pleural surface—the parietal pleura and the visceral pleura.  Either layer can be transformed by the infiltration of cancerous tumors from a smooth membrane into a lumpy surface that produces excess fluid and restricts breathing.

Malignant mesothelioma of the pleura is diagnosed in about two-thirds of all mesothelioma cases.  Because it is the most common type of the disease, pleural mesothelioma has been studied the most, and treatment options have been developed specifically to treat it.

Peritoneal mesothelioma

The next most common form is peritoneal mesothelioma, which accounts for the majority of the remaining cases.  The incidence of peritoneal mesothelioma appears to be on the rise, especially in women.

Like the pleura, the peritoneum has two parts: the visceral peritoneum that covers the intestinal tract directly and the parietal peritoneum that lines the abdomen.  In peritoneal mesothelioma, the tissue develops calcification and plaques that impede its function and eventually become cancerous.

Pericardial mesothelioma

Primary pericardial mesothelioma occurs much less frequently than the first two types. Pericardial mesothelioma develops in the pericardium, which is the multi-layered sac that protects the heart and attaches it to the surrounding walls. There have only been a few hundred cases of pericardial mesothelioma recorded in medical literature.

Tunica vaginalis mesothelioma

Testicular mesothelioma develops in the membranous lining that surrounds the testicle, the tunica vaginalis, which provides protection and support for the reproductive organ.  Tunica vaginalis mesothelioma is the rarest form of mesothelioma.  To date, less than one hundred cases of this type of mesothelioma have been reported.  Reported symptoms include testicular lumps and swelling of the scrotum.

Benign mesothelioma

Very rarely, a non-malignant mesothelioma tumor develops in the pleura or the peritoneum.  These tumors can press on the lungs and cause pain and breathing difficulties that resemble the symptoms of malignant mesothelioma.  But a benign mesothelioma tumor does not spread or invade adjacent tissues. A single benign tumor can usually be removed surgically, curing the benign mesothelioma patient.