Introduction: Kichuchi- Fujimoto disease (KFD) is a rare form of lymphadenitis with benign self-limiting condition. Neurological complications, including aseptic meningitis, cerebellar ataxia, mono neuritis multiplex, polymyositis, and brachial neuritis, are not common. Patient: A 12-year-old boy presented with unilateral cervical lymphadenopathy and fever. Histopathological findings of lymph nodes led to the diagnosis of KFD. The boy revisited our hospital due to severe headache and vomiting one week later. CSF analysis demonstrated pleocytosis (lymphocytic 57%), high protein (312 mg/dL) and low CSF/serum glucose ratio (52/121 mg/dL). The etiology was initially suggestive of tuberculous meningitis, and we started anti-tuberculosis drugs. The next day, he had generalized-tonic-clonic seizures and decreased mentality. Brain MRI revealed increased signal involving posterior area of both hemisphere, and EEG showed diffuse slowing during wakefulness, which were compatible with viral meningoencephalitis. Anti-tuberculosis drug was withdrawn, and IV immunoglobulin and glucocorticoids were taken. He had full recovery without neuropsychiatric deficit 2 weeks later. Conclusion: This CSF finding of high protein and lymphocyte-dominant pleocytosis has not been found in KFD with CNS involvement. To the our best acknowledgement, this is the second case of the encephalitis following KFD with abnormal MRI findings.