Fig. 3

Detailed analysis of the histopathological and computed tomography scan findings suggestive of check-valve mechanism of cavity formation. a, b Yellow arrows show the bronchi flowing into the cavitary lesion. a White arrow indicates the adenocarcinoma in situ (AIS) detected at the partly thickened area of the cavity. b Microscopic findings showing that the AIS is surrounded the bronchi. c AIS detected on the histopathological findings is consistent with the partly thickened wall of the cystic lesion