AN ATTEMPT TO USE THE WHO TYPING IN THE HISTOLOGICAL CLASSIFICATION OF LUNG CARCINOMAS

Abstract

An earlier lung carcinoma material collected during 1968–1971 was re‐examined. The series comprised 175 cases, 91 (52 per cent) of which were detected by biopsy and 84 (48 per cent) at autopsy. The significance of the results was evaluated in the light of the clinical course of the disease, mainly in the light of the survival. Epidermoid carcinomas were classified into two groups, one comprising carcinomas with high or moderate differentiation and another comprising those with slight differentiation, which were then dealt with as separate categories. The distribution was as follows: 68 (38.85 per cent) highly or moderately differentiated epidermoid carcinomas, including 6 of the clear‐cell type which are here classified as belonging to this group, and 27 (15.44 per cent) slightly differentiated epidermoid carcinomas, making up a total of 95 (54.29 per cent). Parvo‐cellular anaplastic carcinomas numbered 52 (29.72 per cent) and adenocarcinomas 15 (8.57 per cent) among which 12 (6.86 per cent) were bronchogenic and 3 (1.71 per cent) bronchiolo‐alveolar. Large‐cell carcinoma, mucous gland carcinoma, combined epidermoid‐adenocarcinoma and carcinosarcoma each occurred once (0.57 per cent). There were a further 7 (4.0 per cent) unclassifiable cases and 2 (1.14 per cent) mesotheliomas. Survival in the two groups of epidermoid carcinomas was seen to differ significantly. As regards the 3 patients with clear‐cell carcinomas survival was notably good. It was difficult histologically to draw a line between the slightly differentiated epidermoid carcinoma and the fusiform and polygonal subtypes of the anaplastic parvocellular carcinoma. Nor was there any significant difference in survival in these groups.