Abstract Number: Esoc2026a2137 Fibromuscular Dysplasia and Cortical Subarachnoid Haemorrhage: A Rare Association Presenting as Transient Ischemic Attack

Abstract Background and aims Fibromuscular dysplasia (FMD) is a non-atherosclerotic, non-inflammatory vasculopathy that primarily affects medium-sized arteries and is a well-established risk factor for arterial dissection and intracranial aneurysm formation. In the context of cortical subarachnoid haemorrhage (cSAH), FMD may be involved through two mechanisms: aneurysmal rupture (more frequently) or arterial dissection. We present a case illustrating this relationship. Methods Case report. Results 70-year-old woman with history of cSAH due to probable cerebral amyloid angiopathy and secondary focal sensory seizures who arrived at the hospital with language impairment and right-hand clumsiness. Multimodal CT suggested a distal left internal carotid artery dissection, along with differential considerations between vasospasm and thrombus at the left M2 segment. Brain MRI gradient-echo sequences revealed areas of signal void within bilateral frontal and parietal convexity sulci, consistent with residual blood products in the context of hemosiderosis, as well as bilateral hemispheric cerebral microbleeds, supporting the diagnosis of cerebral amyloid angiopathy. The patient was diagnosed with a transient ischemic attack (TIA) secondary to left M2 vasospasm in the setting of cerebral amyloid angiopathy, along with suspected FMD based on changes observed in the supra-aortic trunks. Additionally, the patient exhibited cognitive–behavioural disorder, likely related to bilateral frontal damage associated with superficial hemosiderosis. She was discharged on single antiplatelet therapy with aspirin and scheduled for close follow-up. Conclusions This review highlights that, despite FMD predisposes to arterial dissection and cSAH, this association remains uncommon. Moreover, these patients are at increased risk of recurrent vascular events, underscoring the importance of vascular evaluation and close follow-up. Conflict of interest All authors: nothing to disclose. Figure 1 - belongs to Results Figure 2 - belongs to Conclusions