Tuberculosis mostly occurs in the upper and lower dorsal segments of both lobes of the lungs, and is less common in the hilar region alone and can be easily confused with lung cancer in the hilar region. Tuberculosis in the hilar region can be either primary or secondary. The morphology is often both lamellar and nodular. CT findings Tuberculosis in the hilar region is often part of primary tuberculosis or secondary tuberculosis. The bronchial shadow may have irregular wall thickening or luminal narrowing in the bronchus surrounded by the lesion. The density is lighter and the margins are blurred. There is no obvious change in the status and course of the pulmonary vessels in them. The patchy shadow gradually fades outward centered on the hilum. Nodular nodules in the hilar region appear as nodular shadows between the bronchi and vessels in the hilum, which are faint in density and generally not enhanced. The margins may be clear or blurred. The contour is shallowly lobulated. Small punctate calcifications may be present within them. There are other focal manifestations of tuberculosis in the lung field, i.e., patchy lung field, small nodular shadow with uneven density and blurred margins can sometimes be found connected to the enlarged hilar region with striated shadow. Differential diagnosis 1. Differentiation from pneumonia (1) Medical history: Tuberculosis often has a long cough. Some of them also have blood in the sputum. Pneumonia has a shorter history, with significant fever and increased white blood cells. (2) Density of the lesion: Pneumonia has a more uniform density, while tuberculosis may have small punctate calcifications. (3) Bronchial invasion: Acute pneumonia usually does not invade the bronchi, and the bronchi that penetrate in the pneumonia lesion are normal bronchial manifestations. The bronchus penetrating in tuberculosis can be normal, but it can also have bronchial wall thickening and irregular luminal narrowing. 2. Differentiation from lung cancer (1) Medical history: lung cancer develops at an older age, while tuberculosis in the hilar region develops at a younger age, and the clinical symptoms of lung cancer in this area are lighter than those of tuberculosis. (2) Density of lesion: the density of lung cancer is generally higher and more uniform than that of tuberculosis. Especially, lung cancer has obvious enhancement in enhancement scan, while tuberculosis rarely enhances. (3) Bronchial invasion: Invasion of bronchus by lung cancer is common, while invasion of bronchus by tuberculosis is relatively rare. Lung cancer often interrupts the bronchi, while tuberculosis causes irregular narrowing of the inner wall of the bronchi, small nodules in the lumen or irregular thickening of the bronchial wall.