Kikuchi–Fujimoto disease complicated with brachial plexus neuritis in a young woman: a case report and review of the literature

BACKGROUND: Kikuchi-Fujimoto disease (KFD) is a rare necrotizing lymphadenitis. Brachial plexus neuritis is an exceptionally rare complication of KFD. CASE PRESENTATION: A 31-year-old Asian female was diagnosed with KFD via excisional biopsy of a posterior cervical lymph node. Four days after the biopsy, pain and disability occurred in her left arm and shoulder. While Magnetic Resonance Imaging (MRI) suspected compression of the brachial plexus nerves, the ultrasound indicated inflammatory changes consistent with neuritis. Diagnosis was challenging; however, distinguishing between mechanical compression and inflammation was crucial. Instead of surgery, steroids and intravenous immunoglobulin (IVIG) were prescribed, and her pain was relieved within 1 week, while her disability did not disappear until 9 months later. CONCLUSIONS: We report a rare case of KFD-associated brachial plexus neuritis emerging shortly after lymph node biopsy. We hypothesize that surgical positioning or traction, superimposed on the KFD inflammatory background, may precipitate this condition. Clinicians should be vigilant for this complication to ensure prompt anti-inflammatory treatment and avoid unnecessary secondary surgeries.