Case report: a rare case of left-sided sinus of Valsalva aneurysm with concomitant coronary artery fistula and carotid artery aneurysm.

Background: Sinus of Valsalva aneurysms (SVAs) are rare cardiac anomalies often occurring with co-existing cardiac lesions, such as ventricular septal defects and aortic regurgitation. While often asymptomatic, SVAs can lead to severe complications, including rupture, aortic regurgitation, and dissection. Carotid aneurysms are also uncommon and pose a significant stroke risk if left untreated. Case summary: We report the case of a 56-year-old woman who initially presented with a pulsatile right neck mass and was diagnosed with a right internal carotid artery aneurysm. Subsequent imaging revealed a 45 mm left-sided sinus of Valsalva aneurysm (SVA) and a concomitant coronary artery fistula involving the right coronary artery. She underwent staged surgical management with a modified Bentall procedure and later excision of the carotid aneurysm. Post-operative recovery was uneventful. Genetic testing later confirmed a diagnosis of Marfan's syndrome. Discussion: SVAs originating from the left coronary sinus are exceedingly rare, but their potential for fatal complications demands early intervention. This case demonstrates that surgical repair of the left SVA, associated coronary fistula, and carotid aneurysm is both safe and effective, and it reinforces the role of genetic testing in patients with atypical presentations of aneurysmal disease. Multimodal imaging and a multidisciplinary approach are essential in guiding treatment decisions in such unusual presentations.