title: Histological typing of lung tumours.
abstract: The WHO Histological classification of Lung Tumours, published in 1967, has been revised. The main features are as follows: Squamous cell carcinoma (epidermoid carcinoma) has the same definition as in the original version, i.e., the identification of keratin and/or intercellular bridges by light microscopy. Three degrees of histological differentiation are described. Dysplasia and carcinoma in situ are discussed. Small cell carcinoma is divided into oat-cell carcinoma, an intermediate cell type and a category for oat-cell carcinomas combined with other major types. Adenocarcinoma includes the acinar, papillary and bronchiolo-alveolar forms and the solid carcinomas with mucus formation (previously part of the large cell carcinoma group). Mesothelial tumours are divided into fibrous, epithelial and biphasic subtypes. A number of less common tumours and tumour-like lesions are defined.
mesh_terms: D000230:Adenocarcinoma / Q000473:pathology; D002282:Adenocarcinoma, Bronchiolo-Alveolar / Q000473:pathology; D000236:Adenoma / Q000473:pathology*; D018288:Carcinoma, Small Cell / Q000473:pathology*; D002294:Carcinoma, Squamous Cell / Q000473:pathology*; D006222:Hamartoma / Q000473:pathology; D006801:Humans; D008175:Lung Neoplasms / Q000473:pathology*; D008654:Mesothelioma / Q000473:pathology; D010212:Papilloma / Q000473:pathology*; D012983:Soft Tissue Neoplasms / Q000473:pathology; D014944:World Health Organization