Small proliferative foci between the oblique fissures of both lungs refer to the fibrous scar foci left in the oblique fissures of both lungs after the treatment of pneumonia or tuberculosis or after self-absorption, which are inflammatory and self-repairing. Chest CT shows small nodular shadows with high density at the oblique fissures of both lungs, which may be accompanied by calcification. Generally do not need to be treated. 1. After the local lung tissue damage of pneumonia or tuberculosis, the surrounding naive connective tissue proliferates to form granulation-like red granular soft tissue, which contains a large number of newborn capillaries and newly born fibroblasts and a certain number of inflammatory cells, which dissolves and absorbs the foreign matter and fills the defect, and then the granulation tissue gradually matures and transforms into scar tissue. 2. Small proliferative foci between the diagonal fissures of both lungs are generally benign lesions, which basically do not impair lung function, and usually do not have clinical symptoms such as chest pain and cough, so they do not need to be treated. If the small proliferative foci between the oblique fissures of both lungs have symptoms such as chest pain or cough and chest tightness, it is recommended to go to the hospital for further diagnosis and treatment.