Mesothelioma Malignant Mesothelioma is a form of cancer that develops in thin layer of tissue that covers most of your internal organs. The majority of mesothelioma cases are found in the lining (pleura) of the lungs. Other, less common forms develop in the lining around the testicles or the heart. https://telegra.ph/9-Lessons-Your-Parents-Taught-You-About-Filing-A-Mesothelioma-Lawsuit-06-14