There is a mass in the lungs 5 cm in size, it may be a cyst, besides cysts, other lesions can also cause masses in the lungs, mainly including lung cancer, lung abscess, and tuberculosis ball and so on. 1. Cyst: if it is a cyst, it is mainly manifested as liquid density, with thin wall visible around the shadow, enhanced scanning and no enhancement inside. 2. Lung cancer: it is a soft tissue mass in the lung, with uneven density, uneven margins, visible burrs and lobes and other malignant signs, with uneven enhancement on the enhanced scan, and malignant cells can be found on pathological puncture biopsy. 3. Lung abscess: caused by infection, with pus cavity in the middle, uniform thickness of peripheral wall, no obvious wall nodules, and clinical manifestation of coughing up pus-flavored sputum. 4. Tuberculosis ball: belongs to the tuberculosis infection after the formation of a kind of caseous granulation tissue, the lesion can be seen inside the calcification, most of the edges are smooth, the physical condition of the decline, can appear tuberculosis recurrence. The presence of a 5-centimeter mass in the lungs accompanied by a pronounced cough, chest pain, coughing up blood, etc., you need to consult a doctor in time to observe and diagnose the specific condition and then do standardized treatment.