Multidisciplinary Treatment for Multiple Dural Arteriovenous Fistulas/Arteriovenous Malformation Associated with Congenital Protein S Deficiency: A Case Report and Literature Review

Congenital protein S deficiency, caused by <i>PROS1</i> gene variants, is a hereditary thrombophilia associated with venous thrombosis. Cerebral venous sinus thrombosis can lead to dural arteriovenous fistula; however, the optimal management of dural arteriovenous fistula in this setting remains unclear. We present a 50-year-old man with multiple intracranial dural arteriovenous fistulas and an arteriovenous malformation associated with confirmed protein S deficiency. The patient had a prior history of thrombosis at the superior sagittal sinus and left transverse sinus treated with anticoagulation at age 41. Digital subtraction angiography at age 49 revealed a de novo left temporal arteriovenous malformation (Spetzler-Martin grade II), left parietal dural arteriovenous fistula (Cognard type III), and anterior skull base dural arteriovenous fistula (Cognard type III) while the superior sagittal sinus and left transverse sinus remained patent. The patient was referred to our hospital due to a residual nidus following arteriovenous malformation resection at a previous institution. Transarterial embolization using Onyx and n-butyl-2-cyanoacrylate achieved complete occlusion of the dural arteriovenous fistulas, and stereotactic radiosurgery using Gamma Knife was subsequently performed for the residual arteriovenous malformation. A thrombophilia workup revealed markedly reduced protein S activity and a homozygous <i>PROS1</i> p.Lys196Glu variant. Long-term oral anticoagulation was initiated, and no recurrence or new thrombotic events were observed during the 6-month follow-up period. This case highlights the importance of considering congenital thrombophilia in patients with multiple arteriovenous fistulas/arteriovenous malformations. Genetic testing combined with a multidisciplinary treatment strategy tailored to the underlying prothrombotic state can contribute to favorable clinical outcomes.