LAUSR

Abstract Rationale: Spontaneous obliteration of unruptured arteriovenous malformations (AVMs) is rare. It occurs in <1.5% of cerebral AVMs and only 7 cases have been reported so far. This phenomenon, together with the formation and outcome of cerebral AVMs, remains barely understood. In this work, we presented a case that spontaneous venous thrombosis in main draining veins of an unruptured AVM were confirmed, and reviewed the relevant literature in order to discuss the possible mechanisms. Patient concerns: Clinical data and treatment of a 33-year-old man with a preliminary diagnosis as right parietal mass with secondary epilepsy. Diagnoses: The diagnosis of the mass was a right parietal arteriovenous malformation (AVM) that was 3.5 cm in size and supplied mainly by multiple feeders of right middle cerebral artery (MCA). Interventions: An operation was performed with meticulous hemostasis of the extracranial soft tissue and the AVM was resected completely. Outcomes: The patient's neurological deficits improved postoperatively and he was subsequently discharged 1 week after surgery. Lessons: Thrombosis of the draining veins may be due to venous stagnation. Spontaneous venous thrombosis in an unruptured AVM is rare. Spontaneous obliteration of an AVM can occur by 2 mechanisms: occlusion of the feeding arteries or of the draining veins. Surgical or interventional treatment of an unruptured AVM with thrombosed draining veins is highly controversial now. However, we favor an aggressive treatment strategy.