Risk factors for malignant mesothelioma

Contact with asbestos is the major risk factor for mesothelioma. Asbestos is used in the manufacture of insulation and fireproof materials, tiles, brake pads, etc. After establishing the relationship of exposure to asbestos and the development of mesothelioma using this substance has decreased dramatically.

The risk of developing mesothelioma depends on the intensity and duration of exposure to asbestos. Prolonged contact at a young age greatly increases the risk of mesothelioma. The period of time after the first exposure to asbestos before the diagnosis of tumors is 20-50 years.

Smoking by itself does not affect the increase in the incidence of mesothelioma, but the combination of smoking and asbestos exposure significantly increases the risk of lung cancer. In smokers exposed to asbestos, the risk of lung cancer increased in 50-90 times compared with the general population. For the prophylaxis (prevention) of mesothelioma should avoid contact with asbestos at home and at work.

Pathogenesis of pleural mesothelioma is insufficiently studied, however, found that asbestos fibers have tropism for serous membranes. Of the respiratory tract, they migrate to the pleura, which can accumulate in large quantities and serve as a trigger for the development of tumors. Because lymph flow, directed towards the parietal pleura, tumor cells implanted in her, and gradually spread over the entire surface. Thus, in the tumor process involves both visceral and parietal pleura sheets, which leads to disruption of lymphatic circulation, rapid accumulation of fluid in the pleural cavity.

By histological classification of WHO (1999), malignant mesothelioma are divided into the following options (types):

• epithelioid type, constituting 50-70% of all mesotheliomas and having the best prognosis (outcome)
o Sarkomatoidny type (7-20%)
o Mixed type (20-35%)
The most unfavorable is frequent sarkomatoidny variant tumor. Effusion in the pleural cavity is at 60-80% of patients, but gradually growing tumor can cause the complete obliteration of the pleural cavity.



Note to Figure
Malignant mesothelioma of the pericardium:

A - mild atypical mesotelium strands and forms a slit-like structure. Fibrous framework of the extended fuksinpolozhitelnyh cells. Coloring pikrofuksinom. h150;

B - part of the increased number of slit-like and tubular structures. Stained with hematoxylin and eosin. h150;

C - solid accumulations mesothelium. Stained with hematoxylin and eosin. x 150;

D - the predominance of solid and tubular growths. Stained with hematoxylin and eosin. õ300;

F - solid masses of atypical polymorphic mesothelium. Stained with hematoxylin and eosin. õ300.