Peritoneal mesothelioma is a rare and aggressive cancer that affects the lining of the abdomen, known as the peritoneum. Although they’ve historically been treated the same way, there are many differences between peritoneal mesothelioma and pleural mesothelioma, the more common form of the mesothelioma that is found in the lining of the lungs. Because peritoneal mesothelioma symptoms are often subtle, the disease has often spread by the...