Mesothelioma

Introduction:
Mesothelioma is a form of cancer that is almost always caused by previous exposure to asbestos. In this disease, malignant cells develop in the mesothelium, a protective lining that covers most of the body's internal organs. Its most common site is the pleura (outer lining of the lungs and chest cavity), but it may also occur in the peritoneum (the lining of the abdominal cavity) or the pericardium (a sac that surrounds the heart).

Signs and symptoms:
Pleural

• Chest wall pain
• Pleural effusion
• Shortness of breath
• Fatigue or anemia
• Wheezing, hoarseness, or cough
• Blood in the sputum (fluid) coughed up

Abdominal

• Abdominal pain
• Ascites
• Mass in the abdomen
• Weight loss

Pathophysiology:

The mesothelium consists of a single layer of flattened to cuboidal cells forming the epithelial lining of the serous cavities of the body including the peritoneal, pericardial and pleural cavities. Deposition of asbestos fibres in the parenchyma of the lung may result in the penetration of the visceral pleura from where the fibre can then be carried to the pleural surface, thus leading to the development of malignant mesothelial plaques. The processes leading to the development of peritoneal mesothelioma remain unresolved, although it has been proposed that asbestos fibres from the lung are transported to the abdomen and associated organs via the lymphatic system. Additionally, asbestos fibres may be deposited in the gut after ingestion of sputum contaminated with asbestos fibres.

Treatment:

• Surgical approach: palliative decortication for pain control and to improve pulmonary function, surgical resection and intrapleural chemotherapy
• Radiation therapy: post-operatively as a consolidative treatment.
• Chemotherapy: Drugs of choice are cisplatin and pemetrexed, gemcitabine and cisplatin.
  

Prognosis:
Often fatal, poor response to treatment.

Screening:
Screening for asbestos-related disease not recommended for general population, but may be appropriate if history of significant asbestos exposureif history of significant exposure and exertional dyspnea, spirometry and chest x-ray recommended in addition to history and physicalif no evidence of abnormalities, consider high-resolution CT which may reveal pleural-based plaques, CT is more sensitive than chest x-ray for detecting lesions and mild fibrosispresence of plaques indicates significant asbestos exposureif patient has abnormal spirometry results, imaging abnormalities, or suspected asbestos-related conditions, consider full pulmonary function tests, including measurement of lung volumes and diffusion capacity.