The prevalence of abnormalities on brain magnetic resonance imaging (MRI) varies in primary Sjögren's syndrome (pSS) patients and they are generally multiple hyperintense areas in the subcortical and periventricular white matter on T2-weighted and fluid-attenuated inversion recovery sequences. Here, we report brainstem involvement in a patient with pSS that was extensive on MRI, but reversible. The patient's outcome was positive. To our knowledge, a similar case has not previously been described.