A histochemical and ultrastructural study of adenocarcinoma of the lung.

Twenty-five cases of solitary nodular adenocarcinoma of the human lung were studied histochemically and ultrastructurally and their morphological characteristics were compared to the cells observed in the control lungs. Adenocarcinoma cells of the human lung may be classified into following four types: Type A--cells resembling the bronchial goblet cell; Type B--cells resembling the mucous cell of the bronchial gland; Type C--cells resembling the type II alveolar lining cell; and Type D--cells resembling the nonciliated bronchiolar cell. Twenty-one cases belonging to Type D (84%) and two cases to Type B (8%), and one case each to Types A (4%) and C (4%). For the histogenesis of adenocarcinoma of the human lung, nonciliated bronchiolar epithelium may be the most important. A comparison of 10 cases of bronchiolo-alveolar carcinoma with 15 cases of ordinary (acinar and papillary) adenocarcinoma revealed no clear differences either histochemically or ultrastructurally.