Peritoneal Mesothelioma Not Caused by Asbestos Malignant peritoneal mesothelioma forms in the lining of the abdomen. It is less frequent than the pleural type and more women suffer than men. Symptoms of peritoneal msothelioma can be vague, such as abdominal discomfort, weight loss, constipation or diarrhoea. A mesothelioma specialist can