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Langerhans Cell Histiocytosis Presenting With Late‐Onset Sporadic Ataxia

Etiological categorization of sporadic late-onset progressive cerebellar ataxia often is a diagnostic and investigatory challenge. Although Langerhans cell histiocytosis (LCH) may demonstrate cerebellar ataxia in late stages, presentation with cerebellar ataxia as an isolated neurological manifestation is exceedingly uncommon. We report on a 40-year-old male patient who presented with progressive cerebellar ataxia and oral ulcers. Brain MRI showed T2/FLAIR (fluid-attenuated inversion recovery) hyperintensities in pons, midbrain, and bilateral brachium pontis with cerebellar atrophy. Biopsy specimen of the oral lesion showed characteristic immunopositivity for LCH markers CD1a and langerin. Our case report demonstrated that LCH can rarely present as noninvasive, nonmetastatic (paraneoplastic) progressive cerebellar degeneration.