Extracranial arteriovenous malformation and subsequent contralateral cavernous sinus dural arteriovenous fistula showing abducens nerve palsy: illustrative case

BACKGROUND: Extracranial arteriovenous malformations (AVMs) are rare clinical entities and on rare occasions cause neurological symptoms. The authors report a case of an extracranial pterygoid AVM and a subsequent contralateral cavernous sinus dural arteriovenous fistula (dAVF) presenting with abducens nerve palsy. OBSERVATIONS: An 80-year-old woman was referred to the authors’ hospital with left abducens nerve palsy followed by right ophthalmalgia. Magnetic resonance imaging (MRI) showed abnormal vessel staining in the left pterygoid and the right inferior petrosal sinus (IPS). Cerebral angiography revealed a left pterygoid AVM draining into the right IPS via the cavernous sinus (CS). A dAVF in the right CS was also revealed. The right ophthalmalgia disappeared spontaneously, and, 4 months later, the left abducens nerve palsy also disappeared after conservative management. Follow-up MRI showed spontaneous regression of the AVM and dAVF. The disappearance of the dAVF was considered to be due to spontaneous regression of the left pterygoid AVM and the consequent decrease in venous pressure of the CS, and the symptoms eventually disappeared. LESSONS: The authors treated an extremely rare case of extracranial AVM with dramatic changes in vascular structure and symptoms. Understanding of the pathophysiology between symptoms and dynamic changes in the vascular structure is essential for providing the appropriate treatment.