Reactive tonsillar enlargement with strong 18F-FDG uptake after chemotherapy for tonsillar diffuse large B-cell lymphoma.

We describe a 14-year-old boy who exhibited left palatine tonsillar enlargement after 6 cycles of aggressive chemotherapy for diffuse large B-cell lymphoma of the right palatine tonsil. The cervical computed tomography scan at 4 months after completion of chemotherapy revealed enlargement of the left palatine tonsil in addition to the thymus without any clinical symptoms. The F-fluorodeoxyglucose positron emission tomography indicated focal areas of strong F-fluorodeoxyglucose uptake in the left palatine tonsil. Histologic examination confirmed tonsillar hyperplasia with no evidence of recurrence. Reactive tonsillar hyperplasia after chemotherapy is rarely reported.