Pulmonary adenocarcinoma in situ is reclassified as precursor glandular lesions in the fifth edition of WHO classification of thoracic tumours, causing widespread attention and heated debate among domestic thoracic oncologists, radiologists, pathologists and surgeons. We would like to comment on the topic and make a few suggestions on the management of pulmonary nodule during lung cancer screening. We are open to all suggestion and welcome debates.