Oncocytic schneiderian papilloma confined to the sphenoid sinus detected by FDG-PET.

We report a 55-year-old man with oncocytic schneiderian papilloma confined to the sphenoid sinus, which was initially detected by positron emission tomography with 18F-fluorodeoxyglucose (FDG-PET) at a very early stage. Based on CT and MRI findings, we suspected that the tumor was most likely benign; however, positive uptake in FDG-PET suggested malignancy. The patient underwent endoscopic resection of the tumor, and the histopathological diagnosis turned out to be oncocytic schneiderian papilloma. FDG-PET is thought to be a powerful tool to search for malignant lesions, but the present case demonstrates the fallibility of this technique. This should be taken into consideration when interpreting FDG-PET images.