A case of late adult-onset dentatorubral-pallidoluysian atrophy mimicking central pontine myelinolysis

We report the case of a 52-year-old man with late-onset dentatorubral-pallidoluysian atrophy (DRPLA). MRI findings of late-onset DRPLA usually showed the involvement of cerebral white matter lesions with high intensity on T2-weighted images (WI), in addition to brainstem, globus pallidus, and thalamus. But our patient did not present with abnormal manifestation of white matter lesions of the cerebrum. In addition, the appearance of pontine base was remarkably similar to central pontine myelinolysis (CPM). There is no reported case of DRPLA mimicking CPM in the literature, while there is one previous report of CPM with cerebellar ataxia without pyramidal tract involvement, and CPM may exhibit cerebellar ataxia. Although there is differentiation between CPM and DRPLA by the presence of the atrophy of brainstem and cerebellum, the characteristic MRI findings of pontine base may make it difficult to differentiate CPM with cerebellar ataxia from DRPLA with inconspicuous leukoencephalopathy. In such a situation, we should return to the clinical history and background of a patient, and, if necessary, DNA analysis should be performed for a definite diagnosis.