[Adult onset Langerhans cell histiocytosis with progressive cerebellar ataxia and spastic paraparesis].

A 44-year-old woman with progressive cerebellar ataxia and spastic paraparesis was referred to our hospital. Brain MRI showed bilateral high signals in superior, middle, and inferior cerebellar peduncles on the T2 weighted images. After 3 years, her symptoms progressively worsened in spite of various therapies including whole brain irradiation and high dose oral prednisone. No evidence of diabetes insipidus was noted. In MRI, brainstem lesions expanded to both hemispheres of the cerebellum without enhancement by contrast medium. We confirmed diagnosis of LCH by skin biopsy of intractable truncal rash which emerged after neurological symptoms.