The most common type of primary pulmonary lymphoma, accounting for about 70% to 90% of cases, is most often over 45 years of age, in equal proportions of men and women, and can have no underlying disease, or can have dry syndrome or rheumatoid arthritis, or be associated with EBV infection. Less than half of patients have symptoms, such as cough, dyspnea and chest pain, but usually no systemic symptoms. Imaging pulmonary MALT can be of three types: 1. Pneumonia type This type is the most common, i.e. solid alveolar changes with bronchial inflation signs, especially in the middle lobe. Tumor type Isolated annular nodular shadow, about 30%, and central bronchial inflation sign. The infiltrative type presents with diffuse ill-defined ground glass shadow, which may be the early stage of the disease, when the tumor cells have not yet invaded the alveolar tissue. Pleural effusion is rare. It should be noted that MALT is often multifocal, which may hinder the determination of the primary lesion. 10%-20% of pulmonary MALT will be combined with gastric MALT and 15%-20% will be combined with bone marrow lesions, so gastroscopy and bone marrow examination are recommended for these patients. Diagnosis used to rely on surgically resected specimens, but now needle aspiration biopsy is possible, but the latter may not distinguish between reactive lymphoproliferative and lymphocytic interstitial pneumonia. Treatment can be surgically removed if the lesion is solitary, but in patients with multiple lesions and no symptoms, active treatment is usually not required because of very slow progression, and dynamic observation is advocated. Patients with more rapid progression can be treated aggressively with single-agent chemotherapy, radiation therapy, or anti-CD20 monoclonal antibodies. Recently, it has been suggested that MALT lymphatic crypts may be an early manifestation of a systemic disease with mucosal immune dysregulation and therefore early intervention is recommended. The prognosis of this disease is usually good, with a 5-year survival charge higher than 80%, and the recent use of melphalan has improved the survival rate even more. Local and systemic recurrence rates after treatment can be up to 50% but can be controlled by chemotherapy, and age is an important prognostic favorable factor.