Aseptic Meningitis with Cerebellitis Secondary to Histiocytic Necrotizing Lymphadenitis (Kikuchi–Fujimoto Disease): A Case Report

Kikuchi-Fujimoto disease (KFD) rarely involves the central or peripheral nervous system, including the cerebellum. Herein, we present a case of KFD, describing its notable clinical findings, diagnostic approach, management, and outcome. A 23-year-old woman received a diagnosis of KFD 5 months before being admitted to our hospital. She presented with fever, headache, and painful cervical lymphadenopathy; low-dose prednisolone (15 mg/day) was administered. She complained of explosive occipital headaches that awakened her in the middle of the night for 2 weeks. Vertigo/dizziness with projectile vomiting was also noted, followed by double vision, unsteady gait, and slower response on the day of admission. Neurological examination revealed drowsy consciousness, bilateral abducens palsy, scanning speech, left limb dysmetria, and truncal ataxia with marked neck stiffness. Brain magnetic resonance imaging (MRI) revealed focal swelling of the left cerebellum and leptomeningeal enhancement. Cerebrospinal fluid measurements revealed extremely high opening pressure (60 cm H 2 O) and lymphocyte-predominant pleocytosis. No other autoimmune or microbiological etiology was identified. We used dexamethasone (20 mg/day) and mannitol for symptomatic treatment, followed by a tapered dose of prednisolone. She recovered rapidly and became nearly symptom-free upon discharge. Follow-up brain MRI at 1.5 and 9 months indicated complete resolution of previous cerebellar swelling and leptomeningitis. The self-limiting nature of the patient's disease course and negative findings for other possible etiologies suggested the diagnosis of aseptic meningitis with cerebellitis secondary to KFD. Other possible diagnoses, including lymphoma, seemed unlikely after serial follow-up imaging.