18F-FDG Uptake Characteristics in Differentiating Benign from Malignant Nasopharyngeal Lesions in Children

Abstract

The characteristics of FDG uptake in the physiologic and malignant nasopharynx were investigated in the paper which was correlated with either pathologic findings or clinical follow-up. Three patients had pathologically established nasopharyngeal malignancy. In the 3 nasopharyngeal malignancies, 2 had diffusely and expansively increased FDG uptake, and one had asymmetric uptake. Our results indicated that the difference between adenoid hypertrophy and malignancy is asymmetric or diffusely expansive 18F-FDG uptake with or without correlating morphologic lesion on diagnostic CT in children under 10 years of age. The typical characteristics of physiologic and inflammatory 18F-FDG uptake in nasopharynx are symmetrically trapezoid. Diffusely increased nasopharyngeal FDG uptake can be considered physiologic if SUVmax is less than 7.6 but should be carefully assessed by pharyngorhinoscopy if SUVmax is greater than 11 and there is no correlating morphologic lesion on diagnostic CT. The diffusely, expansively increased uptake, and asymmetric uptake in particular, should be considered as malignancy. Further biopsy is especially indicated in patients with retropharyngeal space and bilateral cervical lymph node abnormality but no history of malignancy.