Case Report: Histiocytic Necrotizing Lymphadenitis (Kikuchi-Fujimoto Disease) Concurrent With Aseptic Meningitis.

Kikuchi-Fujimoto disease (KFD), also known as histiocytic necrotizing lymphadenitis, is a rare, benign, self-limiting disease characterized by local lymphadenopathy. Central nervous system involvement in KFD is extremely rare and remains a diagnostic challenge. Only 41 cases of aseptic meningitis associated with KFD have been reported worldwide, with just four cases (including our case) of KFD with meningitis as the first symptom. We report a case of KFD accompanied by aseptic meningitis with severely high intracranial pressure (400 mmH2O), increased white blood cell count (56 × 106/L), and moderately elevated protein level (0.52 g/L). This case is unique in the delayed appearance of lymphadenopathy. After 1 month of treatment with steroids, fever, headache, and lymphadenopathy gradually disappeared, and the result of cerebrospinal fluid examination gradually became normal. In conclusion, based on our case findings and our literature review on KFD with aseptic meningitis, a diagnosis of KFD should be considered when delayed appearance of lymphadenopathy is observed in patients with aseptic meningitis.