Benign mesothelioma is a rare disease characterized by the presence of a fibrous tumor in the pleura, the membrane that surrounds the lungs. The disease is called benign because the tumors are usually not cancerous and usually do not spread to surrounding tissues or to other areas of the body. Nonetheless, the disease can be dangerous if left untreated. The tumors may grow large, placing pressure on the lungs and causing difficulty breathing. Benign mesothelioma is also known as non-malignant mesothelioma and solitary fibrous tumor of the pleura.
It is believed by many in the medical community that malignant mesothelioma is always caused by exposure to asbestos. There is no consensus as to whether the benign form of the disease, which accounts for fewer than one in ten mesothelioma cases, is also caused by asbestos. Since that connection has not been ruled out, however, doctors often see a diagnosis of benign mesothelioma as a warning sign to be on the lookout for other diseases caused by asbestos, including malignant tumors.
A patient with benign mesothelioma may show no symptoms, with tumors discovered during routine examinations. However, they may show symptoms such as a chronic cough, breathlessness, and chest pain, as a result of the tumor pressing on the lung. Other symptoms, resulting from low oxygen in the blood, include clubbed fingers, low blood sugar, and fever. These symptoms are similar to those seen with malignant mesothelioma. Extensive tests may be needed to determine whether a patient has the benign or malignant form of the disease.
Diagnosis usually begins with a review of the patient's medical history and a physical exam. This is followed by chest imaging to locate the tumor, which may include x-rays, computed tomography (CT) scans, or magnetic resonance imaging (MRI). Finally, a biopsy will be performed to determine if the tumor is benign or malignant. This may consist of a tissue biopsy, in which part of the tumor is surgically removed for testing, or a fluid biopsy, in which liquid is extracted from the tumor using a needle.
Benign mesothelioma is usually treated with surgical removal of the tumor. Part of the lung may also be removed. For most patients, surgical treatment results in a full recovery with no recurrence. Some patients develop a buildup of fluid in the cavity surrounding the lungs in the first few days after the procedure, and must remain in the hospital to have additional fluid drawn off. Regular follow-up checkups are recommended, since there is a chance that the tumor may return in either a benign or malignant form.