Bronchogenic carcinoma is characterized by three different patterns of spread: endobronchial, the commonest, submucosal, and peribronchial. While the diagnostic yield of bronchoscopy is very high for endobronchial masses, both submucosal and peribronchial tumors are more difficult to detect, and standard forceps biopsy can be negative. In such cases transbronchial needle aspiration biopsy allows higher diagnostic accuracy. CT findings of extramucosal neoplastic spread are not specific. Thickening of the bronchial walls is the commonest sign, but CT is inaccurate in predicting whether bronchial thickening will result in endobronchial/extramucosal neoplasm, fibrosis or bronchial wall edema. Despite this inaccuracy, CT is complementary to bronchoscopy since it allows to: 1) detect a pathology in the bronchial walls, which appear thickened; 2) delineate the extent of extraluminal spread; 3) help plan transbronchial needle aspiration biopsy.