"Proliferative Keratin Cyst," a Lesion in the Lungs of Rats Following Chronic Exposure to Para-aramid Fibrils

摘要: Cystic and keratinizing squamous lesions have been observed in rats exposed chronically to a number of particulates. A variety diagnostic terms applied these pulmonary but no consensus exists as their most proper morphological classification. In an attempt obtain for cystic produced by Kevlar para-aramid fibrils TiO2 powder, panel medical veterinary pathologists was invited participate workshop addressing the morphology reach on suitable descriptive term. All participants agreed that were not malignant neoplasms. The majority opinion minority (3/13) considered be benign tumors. appropriate morphologic diagnosis "proliferative keratin cyst" (PKC). addition, following text: "The are cysts lined well-differentiated stratified epithelium with central mass. Growth appears occurred accumulation peripheral extension metaplastic change into adjacent alveolar spaces. sharply demarcated except those areas which there has metaplasia alveoli. few mitotic figures dysplasia is absent."