Background: Brainstem venous congestion is a rare but serious complication of the CS-dAVF (cavernous sinus dural arteriovenous fistual).
Case description: A 71-year-old woman presented with right abducens nerve palsy. Brain MRI showed a solitary lesion in the right upper pons. Cerebral angiogram revealed the right CS-dAVF with retrograde venous drainage into the cerebellar cortical veins and the anterior pontomesencephalic vein. The patient was treated with stereotactic radiosurgery, resulting in complete resolution of the pontine lesion and the neurologic symptom.
Conclusion: A solitary brainstem lesion can be caused by CS-dAVF as a rare complication. Careful diagnosis and treatment are important to avoid permanent neurologic deficits.