My grandad developed pleural mesothelioma. It is mesothelioma’s most common form.
Because he worked around asbestos most of his life, the asbestos entered into his lungs when he breathed. The mesothelioma developed because of this. It started attacking the pleural membrane, and he had extreme difficulty breathing.
He got bad chest pains as well. This scared him, and he visited a doctor for a chest x-ray. Unfortunately, the pleural mesothelioma had progressed so far that it could not be treated.