It is also called fibrous mesothelioma, solitary fibrous tumor of the pleura, or pleural fibroma. Benign mesothelioma of the pleura typically appears more often in men than in women.
How is Benign Mesothelioma Different from Malignant Mesothelioma?
The first major difference between this type of tumor and malignant mesothelioma is that it originates in a different location. While malignant mesothelioma starts in the mesothelial cells that line the pleura, benign mesothelioma originates in the tissues under these cells, called the submesothelium.
The second major difference between these two types of tumor is that benign mesothelioma tumors do not usually metastasize. However, the Mayo Clinic Web site offers the following warning:
“In a minority of cases, benign mesothelioma can be very aggressive, despite the term “benign.” For this reason, some doctors now refer to this tumor as solitary fibrous tumor.”
The third major difference is that benign mesothelioma cells may take several years or possibly decades to grow; whereas malignant mesothelioma of the pleura develops rapidly.
Finally, benign mesothelioma is not associated with asbestos exposure.
Does Benign Mesothelioma of the Pleura Cause Symptoms?
According to the Mayo Clinic site, “Solitary fibrous tumor usually doesn’t cause signs and symptoms. Most cases are inadvertently discovered during tests and procedures for other conditions.”
There are, however, patients with benign mesothelioma of the pleura that present with symptoms and these are similar to the symptoms associated with the malignant form of the disease – shortness of breath, persistent coughing, and pain.
The first line treatment for benign mesothelioma of the pleura is surgery in spite of the tumor’s large size. The prognosis is good and the tumor seldom reoccurs after surgical removal.
In a study titled Localized fibrous “mesothelioma” of pleura (submesothelial fibroma), published February 1979, in Cancer, researchers studied the characteristics of 18 cases of solid fibrous tumors of the visceral pleura (the part of the pleura that covers the lung). They found that most of these tumors were about the same weight. When they observed them under a microscope, they saw that the tumors were enclosed in a membrane, originated from the visceral pleura, had a predominance of spindle cells whose structures were made up of white, glassy collagen fibers, had virtually no cell division and had not infiltrated the underlying lung.
The researchers also found that, “Total excision (removal) proved curative in all cases with no recurrences or complications.”
Can Benign Mesothelioma Develop Elsewhere?
This type of tumor may also develop in the lining of the abdominal cavity, or peritoneum, and present either as a solitary fibrous tumor, which appears predominantly in men, or as the rarer form, multicystic benign mesothelioma, which appears more frequently in women. Multicystic benign mesothelioma of the peritoneum can go undiagnosed, even though the appearance of the abnormal tissue is unique, because many doctors do not recognize it.
In a case report titled Multicystic benign mesothelioma of the peritoneum presenting as postmenopausal bleeding and a solitary pelvic cyst—a case report, published January 2004 in Gynecologic Oncology, the authors discuss a case in which a woman with postmenopausal bleeding presented with a single, multiloculated pelvic cyst, meaning a cyst with separations in its mass. A laparotomy, which is an incision in the abdominal wall permitting access to the abdominal cavity, was performed and the tumor was diagnosed as multicystic benign mesothelioma of the peritoneum. Here’s what the authors concluded from this case study:
“We wish to alert gynaecologists of this rare association and the unique appearance of mesothelioma lesions, which many would not instantly recognise. There is a lack of consensus on the treatment and follow-up of MBM (multicystic benign mesothelioma). Most authorities consider curative treatment of MBM is achievable through complete disease cytoreduction (peritonectomy) as carried out in the case.”
What the authors are advocating is surgically removing the part of the peritoneum containing the tumor. The prognosis is also good for this procedure.