Fibromuscular dysplasia in a young female presenting with a ruptured abdominal aortic aneurysm: a rare case report and review of the literature.

Introduction and importance: Fibromuscular dysplasia (FMD) is a rare, non-atherosclerotic vascular disease that affects medium-sized arteries such as the renal and carotid arteries. Its involvement in the abdominal aorta, which leads to aneurysm formation, is rare. Case presentation: We report the case of a 35-year-old woman who presented with acute abdominal pain, tachycardic but normotensive. Computed tomography angiography (CTA) revealed a ruptured 9-cm fusiform infrarenal abdominal aortic aneurysm (AAA). Emergency open surgical repair with a Dacron graft was performed. Histopathological examination confirmed FMD, showing medial fibroplasia and fragmented elastic fibers. The patient had no risk factors for aneurysm formation, such as hypertension, smoking, or connective tissue disorders. Postoperatively, she recovered uneventfully; mild day-3 hypertension was controlled with amlodipine, and she was discharged on day 7. Follow-up imaging (CTA chest-abdomen and carotid duplex) showed no additional vascular lesions, verifying isolated FMD. Clinical discussion: This case highlights the importance of considering FMD in the differential diagnosis of AAAs, particularly in younger patients without conventional risk factors. The pathogenesis of FMD-associated aneurysms remains poorly understood, which complicates early recognition and management. Surgical intervention is the primary treatment for ruptured AAAs, with open repair using synthetic grafts being standard practice. Owing to the rarity of FMD-associated AAAs, data on the efficacy and long-term outcomes of endovascular aneurysm repair in this context are limited. To our knowledge, this is the first documented case of a large, ruptured fusiform infrarenal AAA caused by histologically proven FMD in a young woman. Conclusion: FMD should be considered as a potential cause of AAAs in young patients who lack traditional risk factors. Early recognition and appropriate surgical management are crucial to improve patient outcomes. Further research is necessary to better understand the pathophysiology of FMD-associated aneurysms and optimize treatment strategies.