Mesothelioma Pleural Fibroma tumors. There are usually two types: benign (solitary) and malign/ant (diffuse). The biological behaviour of the mesothelioma cancer can be usually predicted by their gross appearance – those that form solitary, discrete masses are generally benign, whereas the other type, who grows diffusely, are usually malignant.
Benign or solitary mesothelioma tumor is also called pleural fibroma. The exposure to asbestos plays no role on the aetiology of benign mesothelioma. Generally speaking it consists of a solitary type, circumscribed, small, firm mass, generally less than 3cm in diameter. Cut surface shows spirals of dense fibrous tissue. Microscopically, the tumour is predominantly composed of curls of collagen fibres and reticulin with interspersed fibroblasts. Rarely, mesothelial-lined clefts are seen in the tumor. Benign mesothelioma causes no symptoms and is detected as an incidental radiologic finding. Sometimes the tumour is associated with systemic syndrome of osteoarthropathy or hypoglycemia. Removal of the tumour is generally curative.
Malignant or diffuse mesothelioma is rare. It is a highly malignant tumor associated with high deadly rate. The tumor is significant in view of its acknowledge association with occupational job’s exposure to asbestos fibers for a large number of years, sometimes more than 20 years. About 90% of malignant mesothelioma tumors are asbestos related which means that the patients were in direct or indirect contact with this mineral. Mechanism of carcinogenecity by asbestos is not quite clear but it appears that prolonged exposure of the mineral type of asbestos with people swallowing and breathing it is capable of inducing oncogenic mutation in the mesothelium.
Asbestos is the commercial name for a group of hydrated magnesium silicate fibrous minerals. There are two major types: serpentine and amphibole. Ninety percent of the asbestos currently used in the United States is Canadian chrysotile, a serpentine fiber that is reportedly less carcinogenic.
Asbestos is valued in industry for its resistance to heat and combustion. It is still used in cement, ceiling and pool tiles, automobile brake linings, and in shipbuilding.
The annual incidence of mesothelioma in the United States is estimated to be approximately 3300 cases per year. The incidence of mesothelioma in the United States appears to have peaked around the year 2000 and is now declining, probably due to control of exposure to asbestos.
The incidence is increasing in many other places in the world, particularly in Great Britain, where a peak of up to 2500 deaths per year is expected around the year 2015. After that time, mesothelioma rates are expected to drop in England and other developed countries because of recent laws and legislation aimed at controlling the use and reducing asbestos exposure in the workplace and the general environment. In contrast, mesothelioma incidence rates are predicted to raise dramatically in the third world derived of the poor regulation on asbestos mining and the intensive use of asbestos in industrial and household applications.
Mesothelioma Pleural Fibroma tumors should reduce in numbers in the next 15 to 20 years but lets not forget that this disease takes between 20 to 40 years to develop and show up. Lets hope that all governs of the world have already put a break to this problem that will be affecting so many people in the next years.
