Squamous Cell Carcinoma, Lung, Rat

The gross appearance of spontaneous squamous cell carcinomas of the rat lung has apparently not been described in the literature. Squamous cell carcinomas induced in the rat lung by polycyclic hydrocarbons are seen grossly as solid masses containing central areas of friable material (keratin) (Shabad and Pylev 1970). Naturally occurring squamous cell carcinoma in man tends to arise in the hilar region and is thus more centrally located than other tumor types, which may arise in the periphery of the lung (WHO 1982). Induced squamous cell carcinomas of the rat lung often arise at the site of application of the carcinogen. A site predilection for the naturally occurring squamous cell carcinoma of the rat lung has not been reported.