Clinically, through imaging examinations of both lungs, including X-ray, CT or MRI of both lungs, nodules in the lungs are found to present with clear borders, and in most cases are benign nodules, and rarely appear to have malignant nodules. The most common type of nodules with clear borders and intact structure, without mucous or infiltration, are inflammatory pseudotumors. Inflammatory nodules in the lungs are mainly caused by infections such as Mycobacterium tuberculosis, Staphylococcus aureus, Klebsiella, and even fungi. After the inflammation has completely subsided and cured by standard anti-inflammatory treatment, nodules of the lung with varying degrees of fibrosis and calcification are left behind, most of which are benign lesions.