Paroxysmal dysarthria and ataxia in chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids

We describe the clinical and imaging features of a unique case of chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids. A 58‐year‐old man presented with development of mild ataxia. Magnetic resonance imaging showed punctate enhancement in the pons, brachium pontis, midbrain and cerebral white matter. Midbrain lesions involved the bilateral red nuclei with ring‐like enhancement. Treatment with steroids resulted in improvements in mild ataxia and brain lesions. However, several days after steroid therapy, the patient presented with paroxysmal dysarthria, and limb ataxia recurred a couple of dozen times each day. Single photon emission computed tomography showed hypoperfusion in the bilateral parietal lobes. After treatment with carbamazepine, symptoms and parietal hypoperfusion improved. Late‐onset paroxysmal dysarthria‐ataxia and parietal hypoperfusion might have been caused by interruption of the cerebellothalamocortical tract at the level of the ring‐like enhancing red nuclei lesions in chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids.