AAH stands for atypical adenomatous hyperplasia, and atypical adenomatous hyperplasia of the lungs is a pathologic term that stands for the early stages of lung adenocarcinoma. The typical progression of lung adenocarcinoma is usually through the processes of atypical adenomatous hyperplasia, carcinoma in situ, microinvasive adenocarcinoma, and invasive adenocarcinoma, which is also known as typical lung adenocarcinoma, but some lung adenocarcinomas may not go through the above process and directly develop into invasive lung adenocarcinoma. Atypical adenomatoid hyperplasia will be manifested as a shadow of ground glass on chest CT, which is usually less than 5mm in diameter. With the progress of the disease, the shadow of ground glass will gradually expand, and will gradually develop into invasive adenocarcinoma with the appearance of real component, and if the real component gradually increases, it will develop into invasive adenocarcinoma. Therefore, if glassy shadow is found in chest CT examination, it should be closely followed up, and if the development of glassy shadow conforms to the above process, it is highly suggestive of lung adenocarcinoma, and active measures should be taken, such as lung aspiration biopsy to further clarify the diagnosis, or direct surgical treatment.