Mesothelioma in man and experimental animals.

Abstract

Asbestos has been established as the cause of most cases of diffuse malignant mesothelioma occurring in the industrialized world. The morphology of mesothelioma may be complex, and the employment of chemical, histochemical and ultrastructural studies are often helpful in identification. Diagnostic difficulties may to some degree blur the extent of its prevalence and reliance on exposure history may not reveal its association with asbestos. Reference panels can be useful in assessing the former and analysis of lung tissue asbestos content may help to clarify the latter, especially in the low dose range. Electron microscopy may prove to be of assistance in this respect, possibly with particular attention to the peripheral areas of the lung. Animal experimentation has supported epidemiologic conclusions and revealed the phenomenon of fiber carcinogenesis. The morphology of mesothelioma in experimental animals is very similar to that in humans, including ultrastructural and biochemical features.

Disseminated sclerosing peritoneal mesothelioma in a dog

“…3 Asbestos exposure, which has been implicated in the development of pleural mesothelioma in human beings, 13 is considered to be a risk factor in canine mesothelioma as well. 9 Mesothelioma has been experimentally induced in rats by injection of asbestos, glass fibers, aluminium oxide, and Simian virus 40 15,18 ; however, the precise role of asbestos exposure and development of mesotheliomas in domestic animals is currently unknown. Malignant mesothelioma preferably metastasizes via lymphatic routes, even though distant metastases are rarely reported.…”

Invasive Epithelial Mesothelioma in a Dog

“…Mesothelioma is a rare neoplasm arising from the lining cells of the peritoneal, pleural, and pericardial cavities or the tunica vaginalis of the testis. 13 Spontaneous mesothelioma has been reported in humans as well as in many species of animals, including dogs, cattle, goats, horses, rats, and hamsters, 7 but is most common in cattle, where it may be congenital. 8 Mesothelioma is associated with exposure to asbestos in humans 3 , 6–10 , 12 , 13 and potentially in dogs.…”

“…The tumor has been experimentally induced in rats and hamsters by inhalation or injection of asbestos, glass fibers, and aluminum oxide. 7 Mesothelioma has also been induced in rats by intracavitary injections of the simian virus 40 (SV40). 10 There are distinct histologic patterns: epithelioid (resembling carcinoma), sarcomatoid or sclerosing (resembling fibrosarcoma), and biphasic mesothelioma.…”