Giant dissecting aneurysm of the superior mesenteric artery with distal branch involvement and true lumen collapse: a case report

Background Isolated superior mesenteric artery dissecting aneurysm (ISMADA) is rare and may lead to fatal outcomes. This case report presents the surgical management of a patient with a giant ISMADA complicated by suspected impending rupture. Case presentation A 70-year-old man was admitted with a 2-year history of intermittent abdominal pain that had worsened over the preceding 2 days. Examination revealed a 5 × 5 cm pulsatile periumbilical mass with tenderness and mild lower abdominal tenderness with questionable rebound. Computed tomography angiography showed a 4.8 cm isolated superior mesenteric artery dissecting aneurysm involving distal branches, with severe true lumen compression. Laboratory tests showed mild leukocytosis. Emergency resection of the aneurysm with prosthetic graft reconstruction of the superior mesenteric artery was performed in a hybrid operating room. Postoperative angiography confirmed graft patency. The patient resumed oral intake on postoperative day 4 and was discharged uneventfully on day 8. At 30-month follow-up, he remained asymptomatic without abdominal or gastrointestinal complaints. Conclusion Although rare, isolated superior mesenteric artery dissection can progress to aneurysmal degeneration, rupture, and hemorrhage. Most uncomplicated ISMAD cases can be managed conservatively, and endovascular therapy is feasible in anatomically suitable patients; however, open surgical repair remains indispensable in selected complex cases.