[Follicular lymphoma showing long-term false positive results by FDG-PET after rituximab-containing chemotherapy].

We report a patient with follicular lymphoma who had false positive results on 18-fluorodeoxyglucose positron emission tomography (FDG-PET) tests for more than six months due to inflammatory reactions continuing over a long period of time after chemotherapy with rituximab. Although FDG-PET has advantages over other imaging methods when used for the evaluation of the response to chemotherapy and detection of recurrence, attention should be paid to the possibility of false positive results due to such inflammatory conditions, especially when rituximab is administered. Biopsy of the FDG-uptake lesions is strongly recommended if recurrence is suspected.