Oat-cell carcinoma of the lung. Its origin and relationship to bronchial carcinoid

Abstract

Electron-microscopic examination of normal bronchial epithelium and mucous glands has revealed the presence of cells similar in appearance to Kultschitzky (argentaffin) cells in the intestinal canal. The cells, which possess long cytoplasmic processes, are present in small numbers at all levels of the bronchial tree and are found adjacent to the basement membrane. They contain characteristic cytoplasmic granules referred to as neurosecretory-type granules, which are similar to those present in intestinal argentaffin cells, adrenal medullary cells and sympathetic nerve endings. Eighteen bronchial carcinoid tumors and 22 oat-cell pulmonary cancers have also been found to contain similar neurosecretory-type granules in the tumor cell cytoplasm. On the basis of light-microscopic similarities and the production of similar common patterns of hormonal disturbances and the possession of similar ultramicroscopic features, it is suggested that oat-cell pulmonary cancer and bronchial carcinoid tumors are closely related. They may be, respectively, the malignant and locally malignant form of tumors derived from Kultschitzky-type cells normally found throughout the bronchial tree.