Kikuchi–Fujimoto Disease: A Rare Etiology Behind Pediatric Cervical and Supraclavicular Lymphadenopathy: A Case Report

<b>Background and Clinical Significance:</b> Cervical lymphadenopathy is a common condition in children, most often caused by reactive hyperplasia due to viral infections, followed by bacterial infections and, less commonly, malignancies. Supraclavicular lymphadenopathy in children warrants thorough evaluation due to its higher association with malignancy compared to anterior cervical lymphadenopathy. Kikuchi-Fujimoto disease (KFD) is a rare, benign, and self-limiting condition characterized by cervical lymphadenopathy, predominantly affecting young adults-especially Asian women-and is rarely observed in children. We present a case of a 14-year-old girl with cervical and supraclavicular lymphadenopathy diagnosed with KFD. <b>Case Presentation:</b> A previously healthy 14-year-old girl was admitted with a 20-day history of cervical and supraclavicular lymphadenopathy, fever, and 5 kg weight loss. Laboratory investigations revealed leukopenia and lymphopenia, with a weakly positive ANA titer (1:160) and no other significant abnormalities. Extensive infectious workup was negative. Cervical ultrasound showed multiple enlarged, hypoechoic, rounded lymph nodes. CT imaging revealed paraaortic lymphadenopathy without additional findings. Due to the persistence of lymphadenopathy and inconclusive workup, a lymph node biopsy was performed to rule out malignancy. Histopathology was consistent with Kikuchi-Fujimoto disease. <b>Conclusions:</b> This case highlights a rare pediatric presentation of KFD, particularly notable for supraclavicular lymphadenopathy. It underscores the importance of considering a broad differential diagnosis in persistent lymphadenopathy, including rare conditions such as Kikuchi-Fujimoto disease.