Gross classification of 175 cases of rat pleural mesothelioma induced by chrysotile.

This paper reports an analysis of the gross pathologic classification of 175 cases of rat pleural mesothelioma induced by chrysotile. The mesotheliomas were divided into diffuse and localized types, and further into four subtypes according to the form of the tumors (massive, nodule, plaque, and mixed). Diffuse pleural mesothelioma accounted for 58.9% of the tumors and occurred mainly as the nodular type. Among the localized type (41.1%) the massive subtype was most prevalent.