A 22-year-old man presented with an acute altered mental status, left third cranial nerve palsy, ataxia, and right side weakness, all of which suggestive of brainstem encephalitis. Six months earlier, he had persistent fever, myalgia, and weight loss. Soon after fever resolution, oral and scrotal ulcers, usually painless, appeared accompanied by acneiform skin lesions in the chest and arms. At the time, antibiotic treatment led to partial regression of the lesions.Brain magnetic resonance imaging (MRI) showed hyperintense lesions on left midbrain, thalamus, and subcortical regions (Fig. 1). Cerebrospinal fluid analysis showed only mild lymphocytic pleocytosis. Pulse therapy with methylprednisolone 1 g/day for 7 days followed outstanding clinical improvement, although residual right hemiparesis and kinetic tremor remained. At discharge, he was on prednisone 20 mg/day and azathioprine 150 mg/day. Four months after therapy onset, a control brain MRI demonstrated resolution of most lesions along with signal alteration and enlargement of the olivary nuclei in the left medulla (Fig. 2a). At the time, he presented only minor oculopalatal myoclonus. Clinical stability and imaging pattern of the lesion suggested a benign finding, and no further investigation was pursued.Six years later, brain MRI showed an atrophic left midbrain peduncle with less evident olivary degeneration. In addition, there was significant atrophy of right cerebellar hemisphere (Fig. 2b) and shrinkage of midbrain (Fig. 2c, d). At that point, the patient had only mild right hemiparesis and oculopalatal myoclonus. Azathioprine 150 mg/day was his only medication, and he remains stable until this moment.