Abstract
Ciliated muconodular papillary tumor (CMPT) is a rare benign lung tumor characterized by ciliated columnar cells, mucous cells, and basal cells. Herein, we report a case of CMPT with 11 years of preoperative follow-up, depicting the natural course of the tumor and changes in computed tomography (CT) findings. A 39-year-old man had a 5-mm solid pulmonary nodule in the right lower lobe that had slowly grown and transformed into a thin-walled cavitary lesion. Right lower lobe lobectomy was performed and the tumor was confirmed to be a CMPT. Although it is difficult to diagnose CMPT with CT findings alone, CMPT should be considered as a possible diagnosis when a slowly growing nodule undergoes cavitary changes.