Kikuchi-Fujimoto disease can present as delayed lymphadenopathy after COVID-19 vaccination.

Following COVID-19 vaccination, ipsilateral axillary and cervical lymphadenopathy may occur, called vaccine-related hypermetabolic lymphadenopathy, which is considered reactive lymphadenopathy. We report here a case of Kikuchi-Fujimoto disease, which occurred three months after vaccination with COVID-19 vaccine. The patient had cervical and axillary lymph node enlargement and a short-term fever that resolved spontaneously after the first and second vaccines. On the 90th day after the first vaccination, the patient developed a high fever and pathologically diagnosed necrotizing lymphadenitis in the axilla, which was diagnosed as Kikuchi-Fujimoto disease. Gallium scintigraphy showed localized swelling and strong uptake in the ipsilateral axilla. It implies the possibility of Kikuchi-Fujimoto Disease in axillary drainage lymph nodes in association with COVID-19 vaccine. Although only a few cases have been reported so far, this case is novel because of its later onset and diagnosis based on pathological and gallium scintigraphy imaging findings.