It can be difficult to diagnose mesothelioma because many of the symptoms are similar to those of a number of other conditions, including lung cancer and other types of cancers. At the time of diagnosis, your doctor will first do a physical examination and complete a medical history, including asking about the possibility of prior exposure to asbestos.

    Although there is no early detection test for mesothelioma, there are several tests that can be used to help in making the diagnosis of mesothelioma, including a chest x-ray, a CT scan, or an MRI scan. A chest x-ray yields an image of the lungs that will show many types of abnormal changes. A CT scan (computed tomography) is a type of x-ray, but it uses a computer rather than film to create detailed images. An MRI scan (magnetic resonance imaging) uses magnetism, radio waves, and a computer but does not utilize radiation to create a clear image. These tests help your doctor differentiate mesothelioma from other lung tumors as well as determine where the tumor is and its size.

    The average age of onset for malignant mesothelioma is 60 years. There is a long latent period of 20-40 years between exposure and disease expression. Common symptoms include the gradual onset of shortness of breath and nonpleuritic chest pain. The chest pain can be severe and unremitting.A pleural effusion is often the first physical and radiographic finding.Physical signs include dullness to percussion and decreased breath sounds on the involved side. Other radiologic signs include nodular, irregular pleural thickening. Open pleural biopsy is often required to obtain an adequate amount of specimen to make a histological diagnosis.

    Malignant mesotheliomas spread rapidly along the pleural surface, and can rapidly involve the pericardium and contralateral pleura. The tumor may later extend to involve the abdominal lymph nodes and organs.

    The average survival time from the onset of symptoms ranges from 5 months in cases of extensive disease to 16 months in localized cases.Histologic type also correlates with survival time, epithelioid variants show a longer mean and 5 year survival rates.However, approximately 75% of patients die within one year of diagnosis. Treatment has generally been unsuccessful.