Lymph node uptake of 18F-fluorodeoxyglucose detected with positron emission tomography/computed tomography mimicking malignant lymphoma in a patient with Kikuchi disease

[18]F-Fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) is sensitive in detecting a variety of malignancies; however, the specificity is low in differential infections or inflammatory diseases from tumors. We present the case of a female with right cervical lymphadenopathy and fever for 3 weeks who underwent an 18F-FDG PET/CT scan. The imaging showed multiple lymph node enlargement and agglomeration with increased metabolic activity even with the involvement in the abdomen, giving the impression of malignant lymphoma. However, biopsy of the affected nodes proved it to be Kikuchi-Fujimoto disease and the patient was cured after steroid therapy.