Mesothelioma is a cancer that arise from the pleura surroudning the lungs.  Increased incidence among people with heavy exposure to asbestos.  Long latent period of 25-45 years for the development of asbestos related mesothelioma.  Estimated 7-10% lifetime risk for people with heavy exposure of asbestos.  If they smoke, there is greater chance of dying from lung carcinoma rather than mesothelioma.  Evidence of exposure includes asbestos bodies and asbestos plaques.

Macroscopic Description of Mesothelioma

Diffuse lesion that spreads in the pleura space, ensheathing and invading local tissue that is usually associated with a pleural effusion.

Microscopy of Mesothelioma

Mixture of two cell types, one of which may predominate.  Mesothelial cells can differentiate into either epithelioid cuboidal, columnar or flattened cells forming tubular or papillary structures resembling adenocarcinoma (epitheliod type).  Particular immunohistochemistry staining needed to differentiate from metastatic disease.

Electron Microscopy of Mesothelioma

Presence of long tonofilaments but absent microvillous rootlets and lamellar bodies.  The mesenchymal type of mesothelioma appears like a spindle cell sarcoma (sarcomatoid type).  The mixed type of mesothelioma contains both epithelioid and sarcomatoid patterns.

Clinical Symptoms of Mesothelioma

Chest pain, dysponoea and recurrent pleural effusions.  Lung is invaded directly and there is often metastatic spread to the hilar lymph nodes, liver.

Prognosis of Mesothelioma

50% die within 12 months of diagnosis, few survive beyond 2 years.  Aggressive surgical, chemotherapy, and radiotherapy may improve the poor prognosis.  Mesothelioma in the peritoneal cavity associated with heavy asbestos exposure may occur.  Other sites you can have mesiothelioma: pericardium, tunica vaginalis, and genital tract.