Ruptured Brain Arteriovenous Malformation Coexisting With Reversible Cerebral Vasoconstriction Syndrome: A Case Report.

Reversible cerebral vasoconstriction syndrome (RCVS) is known to coexist with other vascular lesions; however, the coexistence of a ruptured brain arteriovenous malformation (AVM) and RCVS has not been previously reported. We describe the case of a 48-year-old woman who presented with an acute thunderclap headache followed by left-sided weakness. A noncontrast head CT revealed an acute right frontal intracerebral hemorrhage, extensive subarachnoid hemorrhage, and a right posterior fossa subdural hematoma, a pattern atypical for isolated RCVS. Cerebral angiography demonstrated multifocal vasoconstriction consistent with RCVS. The patient underwent hematoma evacuation, during which a ruptured brain AVM was identified and resected, with histopathologic confirmation. Postoperative cerebral angiography demonstrated no residual AVM. The patient experienced substantial neurological recovery following rehabilitation, with only mild residual left-sided weakness at follow-up. This case underscores the importance of maintaining a high index of suspicion for coexisting vascular lesions in patients with presumed RCVS who present with atypical hemorrhagic patterns.