What causes benign fibrous tumors of the pleura?

What causes benign fibrous tumors of the pleura?

The causes of benign fibrous tumors of the pleura are not known. It is known, however, that exposure to asbestos – the primary cause of mesothelioma tumors – does not cause this condition. Smoking, though discouraged, is also not considered a cause of benign tumors of the pleura.