An approach to a histogenetic nomenclature and classification of lung carcinomas based on the study of 2500 cases.

The recent data concerning the action of carcinogens and cocarcinogens, as well as the role of host factors in the development of lung carcinomas are discussed in relation to 2500 studied cases. The role of basal cell hyperplasia and of metaplastic factors is emphasized. Two developmental patterns could be observed: one characterized by the persistent action of carcinogens on a substrate similar or less different as to the normal one, giving rise to the microcellular, pleomorphous and epidermoid carcinomas, and the other related to the pre-existence of fibrous lesions in the lung which enhance the accumulation of carcinogens and provide for the cylindrocubic, bronchioloalveolar carcinomas and for the pseudoglandular zones of pleomorphous ones. In these views a histogenetic nomenclature and classification of lung carcinomas is proposed.