The epidermoid (squamous cell) carcinomas of the lung. A histopathological analysis of 2,150 diagnosed cases

A histopathological analysis of 2,150 cases of lung epidermoid (squamous cell) carcinomas, diagnosed between March 1949 and December 1983, was performed. The ratio men/women was 14.9:1. The study included 851 lung surgical specimens (199 pulmonectomies, 456 lobectomies and 196 segmentectomies, atypical resections and lung biopsies). 1,103 bronchial biopsies of inoperable cases, 91 peripheral lymph node biopsies, 19 pleuroparietal biopsies, and 86 autopsies. Immature, unkeratinized forms were found in 471 cases, a low tendency to keratinization in 830 cases, and mature, well keratinized forms in 849 cases. Necrosis of neoplastic tissue occurred in 332 cases (15.5 per cent). The most frequent metastases were found in hilar and mediastinal lymph nodes: 71 surgical specimens and autopsies. In the ensemble of histodiagnosed cases of lung carcinomas (between 1949 and 1983), the epidermoid carcinomas of the lung, which presented an incidence of about 55 per cent 15 years ago, have decreased to 36 per cent in the last five years. Differentiating criteria between immature forms of epidermoid, cylindrocubic and macrocellular carcinomas of the lung were established. The importance of epidermoid metaplasia of bronchial epithelium and of intraepithelial proliferations in the histogenesis of epidermoid carcinomas of the lung is discussed in the light of experimental data.