Benign mesothelioma, also known as multicystic or fibrous mesothelioma, refers to non-cancerous tumors within the pleura, which is the lining in and around the lungs. Benign mesothelioma is classified as a fibrosis and is not related to asbestos exposure. It does not produce a pleural effusion. This lining is composed of special cells known as mesothelial cells, which secrete a lubricating substance that prevents the lungs and other organs from rubbing against each other. Men are more often diagnosed with the disease than women are, and it is more common for these nonmalignant tumors to develop in the lungs than in the stomach, heart, or the reproductive organs. The most important difference between benign mesothelioma and the cancerous form is that the benign tumors do not spread to other tissues in the body.
Both benign and malignant mesothelioma tumors are a direct result of asbestos exposure. Airborne asbestos fibers can travel to the ends of the small air passages and reach the lining of the lungs. Once in the lungs, asbestos fibers damage the cells that make up this lining, causing abnormal cell growth, and as a result, the person develops mesothelioma. If the fibers are swallowed, they can also reach the lining of the abdominal cavity where they can cause mesothelioma of the stomach. Consequently, workers involved in industries and occupations where asbestos is produced or used are at a high risk of developing the disease.
Drinking contaminated water, exposure to pesticides and fertilizers that contain vermiculite, or even living in the same household with a person who unknowingly carries asbestos dust home via clothing, hair and/or skin can increase the risk of developing mesothelioma. It can take as long as fifty years for the disease to develop even when a person is exposed to asbestos on a regular basis.
Less than ten percent of all mesothelioma cases are benign. The symptoms of benign mesothelioma are similar to those of malignant pleural mesothelioma; it is almost impossible distinguish between the two. When the doctor suspects that such a tumor exists, he or she may initially perform a simple chest x-ray. Follow-on diagnostic techniques such as CT Scans, MRIs, and open lung biopsies are required to differentiate between malignant and benign mesothelioma.
Approximately half of those affected by benign mesothelioma are unaware the disease because there are no telltale symptoms; these patients only learn of their mesothelioma when the tumor shows up in an X-ray or other
Among the other fifty percent of patients who do experience symptoms, many may find it difficult to breathe due to the crowding of the lungs as the tumor grows. Other symptoms include chronic cough, chest pain, fever, but perhaps the most distinguishing symptom is the presence of clubbed fingers. This symptomatic characteristic develops when dangerously low levels of oxygen in the bloodstream create distorted angles in the nail beds of the patient’s fingers. Patients with lung cancer, heart diseases, and cystic fibrosis may also experience clubbing of the fingers, so this symptom alone is not enough to make a positive diagnosis of benign mesothelioma.
The U.S. Dept of Health and Human Services has a good chart on their website showing the difference between benign and malignant tumors:
Cases of benign mesothelioma are relatively easy to treat. The goal of treating noncancerous mesothelioma is to eliminate the cause of the pain or discomfort which usually requires removing the tumors. Under normal conditions, a surgeon can remove the tumor or tumors in a single operation, and the prognosis is usually excellent in these cases. Complications and a serious health risk may occur if fluid escapes into the pleura of the lungs. After removing the tumor, most doctors recommend their patients continue to have regular check-ups and chest x-rays because benign mesothelioma may be the predecessor of the more serious malignant form of the disease.
Benign asbestos pleurisy is not a mesothelioma, but can be mistaken for one because it also affects people with a history of exposure to asbestos. Indeed, it is estimated that 3% to 5% of asbestos workers contract this pleurisy, after a latency period which is shorter than that of mesothelioma. Other asbestos-related diseases are pleural plaques and pleural calcifications. Benign asbestos pleurisy does produce pleural effusions, leading to suspicion of mesothelioma, especially when combined with a history of asbestos exposure. The pleural effusions associated with the pleurisy usually stops on its own. There have been cases where patients got pleurisy, it cleared up, and the patient later developed mesothelioma.