A pathological description of a cord-like shadow in the left lower lobe of the lung, detected by imaging means such as radiographs and CT of both lungs. This condition requires consideration of respiratory diseases, more commonly inflammatory infections of the lungs, such as pneumonia with invasion of pathogens such as Mycobacterium tuberculosis, Staphylococcus aureus, and Klebsiella. In addition, after pneumonia is identified, the presence or absence of the acute phase of inflammation should be clarified, and if necessary, respiratory secretions should be taken for examination or culture of pathogens, and even drug sensitivity tests may be performed to clarify the cause, condition, and choice of treatment. A rare clinical condition is a malignant tumor of the lung, which is very rare. However, if biopsies are taken for pathological examination, it is clear that the shade is malignant, and early surgical excision and treatment with radiotherapy, chemotherapy, and targeted drugs are needed at this time.