A giant squamous cell papilloma with high fluorodeoxyglucose uptake mimicking squamous cell lung cancer: A case report.

Bronchial papillomas have a median diameter of 15 mm at diagnosis and are classified as benign tumors; however, they may occasionally demonstrate increased fluorodeoxyglucose (FDG) uptake, requiring differentiation from malignant tumors. A 64-year-old man was referred to our hospital after chest computed tomography (CT) performed to evaluate a cough during a routine workplace health checkup revealed a 60-mm mass in segment 6 (S6) of the right lower lobe. The serum levels of carcinoembryonic antigen, cytokeratin 19 fragment, and squamous cell carcinoma antigen were elevated. FDG positron emission tomography/CT demonstrated intense FDG uptake in the right S6 mass, with a maximum standardized uptake value of 23.21. Bronchoscopy revealed a tumor protruding into the right B6 bronchus. Direct biopsy of the endobronchial lesion revealed a papilloma-like lesion composed of stratified mature squamous epithelium. Although no definite malignant features were identified, the possibility of secondary hyperplastic/dysplastic changes associated with neighboring malignancies, such as squamous cell carcinoma, could not be completely excluded. To evaluate the lesion, a CT-guided percutaneous lung biopsy was performed, which revealed similar histological findings without evidence of malignancy. As malignancy could not be definitively excluded, diagnostic and therapeutic surgery, consisting of uniportal video-assisted thoracoscopic right lower lobectomy with bronchoplasty and ND2a-1 lymph node dissection, was performed. Histopathological examination revealed a squamous cell papilloma measuring approximately 46 mm in diameter, with no evidence of malignancy. This squamous cell papilloma was larger and demonstrated higher FDG uptake, compared with previous cases.