Lymph nodes in the lungs are found to be enlarged by imaging tests, such as X-ray and CT of both lungs. Clinically, there are many common causes, such as inflammation of the respiratory system itself, including infection with viruses, bacteria, Mycobacterium tuberculosis, etc., and inflammation of the lungs caused by Leptospira can cause enlargement of lymph nodes in the lungs. Also seen in diseases of the cardiovascular system, such as lymphoma and leukemia can also cause enlargement of lymph nodes in the lungs, which contain a large number of lymphoma and cancer cells. Clinically, blood tests, PPD tests, and pathological examinations of enlarged lymph nodes can be performed to clarify the diagnosis and to avoid delay in treatment.