Ciliated muconodular papillary tumor of the lung: 18F-FDG PET/CT findings of 15 cases

Objective Ciliated muconodular papillary tumor (CMPT) is a rare lung tumor that was first reported in 2002. This study assessed 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) findings of CMPT of the lung. Methods FDG PET/CT findings of 15 patients (eight men and seven women; median age, 67 years) with surgically resected CMPTs were retrospectively analyzed. Size, location, and maximum standardized uptake values (SUVmax) of CMPTs were measured. Histopathological features of the resected tumors were assessed and compared with the FDG PET/CT findings. Results CMPTs were detected as a small pulmonary nodule in all 15 patients. Twelve of 15 tumors were found in the lower lobe of the lung. Mean maximal diameter of the tumors was 9 mm (range 6–14 mm). All but one tumor showed low FDG uptake, with a SUVmax ranging from 0.57 to 1.35. The remaining tumor showed moderate FDG uptake, with a SUVmax of 3.67. Pathologically, tumors with low FDG uptake contained various amounts of mucin and no or only a small amount of lymphocyte infiltration. In contrast, the tumor with moderate FDG uptake had a large cellular component and prominent lymphocyte infiltration. Conclusion CMPT typically shows low FDG uptake.