Atypical hyperplasia of lung nodules is a precursor to cancer and is usually of a different pathology, nature, and degree of risk than carcinoma in situ. The presence of a certain specific proliferation of cells in the lungs is usually clinically referred to as atypical hyperplasia of the lungs, but there is usually a benign possibility of such hyperplasia. This symptom is precancerous, and when it occurs, it may lead to cancer in the patient. However, this disease is not as dangerous as cancer and can be cured with aggressive treatment. Carcinoma in situ refers to the presence of cancer cells in the epithelial layer of the affected area without infiltration or metastasis, but it may involve the whole epithelial layer. In the clinic cancer is usually malignant, and after treatment, patients still have the possibility of recurrence. If treatment is not timely, it may affect the patient’s life. Patients should go to the hospital for examination and treatment in time when they have lung discomfort.