Subject matter experts are trained to distinguish between a benign tumor and a malignant tumor. Benign tumors are not cancerous and any surgeon can remove the tumor without any kind of problem. Because these benign tumors do not spread in the same way that malignant tumors do, these are not recognized as mesothelioma.
However, the malignant mesothelioma is much more common. Only 10 percent of mesothelioma patients are affected by the type pleural benign.