A possible variant of neuro-Behçet disease presenting chronic progressive ataxia without mucocutaneo-ocular symptoms

Masaki Hirose, Takeshi Ikeuchi, Shintaro Hayashi, Kenshi Terajima, Kotaro Endo, Tsunemi Hayashi, Akiyoshi Kakita, Teruo Kimura, Hitoshi Takahashi, Masatoyo Nishizawa

Behçet disease (BD) is a chronic relapsing multisystem disorder of unknown etiology, which preferentially affects the oral and genital mucous membranes, skin, and eyes. Neurological involvement is one of the most serious manifestations of BD, known as neuro-Behçet disease (NBD). We here describe clinical, radiological, and neuropathological findings for two patients with a possible variant of NBD, who manifested progressive ataxia in the absence of mucocutaneo-ocular signs characteristic for BD. Both patients presented a slowly progressive cerebellar phenotype, accompanied by behavioral changes and sphincter disturbance. Brain MRI scan revealed mild atrophy in pons and cerebellum. Both patients showed a mild CSF pleocytosis, and were positive for HLA-B51. The post-mortem examination performed in one patient, showed widespread foci of chronic encephalitis, consistent with the diagnosis of NBD. Steroid pulse therapy was effective in one patient. Identifying the progressive ataxia phenotype of NBD without mucocutaneo-ocular symptoms is important, because these patients may benefit from early steroid therapy.