When adding 22 cases of bronchial adenomata seen in the Brompton Hospital to the more than 100 cases previously documented, Foster-Carter (1941) stated that no death had ever been recorded from malignant change in a bronchial adenoma. Price-Thomas (1954), reporting a personal series of 41 bronchial adenomata treated in the Brompton and Westminster Hospitals, concluded that 'the incidence of malignancy is so low that it is possible for practical purposes to ignore it'. More recent papers have, however, questioned the use of the term bronchial adenoma, emphasizing not only the varying behaviour of the four tumour types included in the term-the bronchial carcinoid, the adenoid cystic carcinoma (cylindroma), the muco-epidermoid tumour, and the true bronchial mucous gland adenoma-but also the differing degrees of malignancy of the bronchial carcinoid itself (Donahue, Weichert, and Ochsner, 1968;Meffert and Lindskog, 1970;Tolis et al., 1972;Turnbull et al., 1972). In a Mayo Clinic series of 215 cases of bronchial carcinoid (Arrigoni, Woolner, and Bernatz, 1972), 23 (11%) were considered to have atypical histological features and, of these, 70% metastasized and 30%/O were dead after a mean survival of 27 months. This is to be contrasted with the usual bronchial carcinoid five-year survival of 80% or more (Overholt, Bougas, and Morse, 1957; Donahue et al., 1967). 245 on 7 May 2018 by guest. Protected by copyright.