Majority of mesothelioma (cancerous tumor affecting mesothelial cells of organs) cases come under the classification pleural mesothelioma. This is a cancer that originates in the pleura, the delicate membrane covering the lungs. Out of these, seventy five percent are diffuse malignant pleural mesethelioma. The balance is localized or benign.

Diffuse malignant pleural mesothelioma is, in most cases, caused by unprotected exposure to asbestos. The symptoms include shortness of breath and/or chest pain, loss of weight, cough, fatigue, swelling on the face, neck and arms, reduced appetite, and coughing up blood. There would be collection of fluid in the thoracic cavity. It may take from twenty to forty years or more after contact with asbestos for the symptoms to emerge. Because of the time lag, diagnosing is often difficult. Moreover, many doctors are not familiar with the disease.

Diagnostic procedure consists mostly of imaging with Computed Tomography (CT scan), Magnetic Resonance Imaging (MRI) and Position Emission Tomography (PET), and laboratory tests and analysis. Thoractomy, which means making an incision through the chest wall to look into the pleura (the membrane lining the lungs and the thoracic cavity) and pleural biopsy provide conclusive evidence.

Diffuse malignant pleural mesothelioma tumor is very aggressive and spreads fast. There are several methods to gauge the stage of the cancer. The most common is known as TNM. T is for the size of the tumor, N for the number of lymph nodules involved, and M for metastasis (spread of the cancer). There are basically four different stages. Correct grading helps the doctors to decide on the course of treatment. If the affliction is detected at an early stage, the chances of longer survival are better.

But generally the prognosis (response to treatment) is not good in diffuse malignant pleural mesothelioma cases. Surgery during Stage I may help. If detected during the later phases of the cancer the survival rate is four months to twelve months. Radiotherapy and chemotherapy do not seem to improve the survival rate. The reality is that currently there is no effective curative treatment. Research is on to find new management methods and more effectual medicines.