Background: Bronchiolar adenoma/ciliated muconodular papillary tumor (BA/CMPT) is listed in the World Health Organization (WHO) Classification 5th edition as a rare benign tumor with papillary growth of ciliary, goblet, and basal cells. Case presentation: The patient was a 67-year-old female in whom a nodular shadow of 20 mm in diameter in the right lower lobe S10 center was found in chest computed tomography (CT) for examination of dorsal pain. Positron emission tomography/computed tomography (PET-CT) showed the accumulation of 18F-fluorodeoxyglucose (FDG) with a standardized uptake value (SUV)max of 13.0. Primary lung cancer was suspected, and surgery was scheduled as a therapeutic strategy. Thoracoscopic resection of the right lower lobe was performed, and possible BA/CMPT or adenocarcinoma was suggested in the differential diagnosis by the intra-perioperative rapid pathologic diagnosis. The final diagnosis was BA/CMPT. Histological findings indicated that the cause of the high FDG-PET scan might be due to many inflammatory cell infiltration in the tumor. Conclusions: We report a resected case of BA/CMPT with exceptionally high FDG accumulation in PET. [ABSTRACT FROM AUTHOR]