Reactive tonsillar enlargement showing strong 18F-FDG uptake during the follow-up of follicular lymphoma.

The 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) has become a standard procedure for the diagnosis, staging, and restaging in lymphoma patients. However, a relative high rate of false-positive results has been reported. We report a case of a 40-year-old man with a previous history of a nodal follicular lymphoma, stage IVA, treated with R-CHOP, which showed strong 18F-FDG uptake in the Waldeyer's tonsillar ring during his follow-up, being considered highly suspicious of relapsed lymphoma. A surgical removal of the palatine tonsils and adenoids was performed, which showed reactive follicular hyperplasia. Furthermore, bone marrow biopsy revealed absence of neoplasia. The patient is still in follow-up with no signs of recurrent lymphoma. This case illustrates that, despite the high sensitivity for the detection of recurrent lymphoma, 18F-FDG uptake should be interpreted with great caution and confirmatory studies should be performed before any therapy.