Sialadenoma papilliferum in the buccal mucosa detected on 18 F-fluorodeoxyglucose-positron emission tomography.

An incidental discovery of an accumulation of 18 F-fluorodeoxyglucose (FDG) in the oral cavity of patients with malignant tumours on FDG positron emission tomography (PET) can pose a problem regarding the differential diagnosis of metastatic lesions. Large accumulations can often be found even when tumours in the salivary or thyroid gland are benign, so FDG-PET is limited in its ability to differentiate between benign and malignant disease. This report describes a rare case of sialadenoma papilliferum in the buccal mucosa that was discovered incidentally on FDG-PET in a patient with multiple metastases to bone after an operation for rectal cancer.