Ruptured Abdominal Aortic Aneurysm Masquerading as Acute Appendicitis.

Ruptured abdominal aortic aneurysm (AAA) is a life-threatening emergency with high mortality. Its presentation is often atypical and may mimic more common abdominal conditions. We report the case of a 65-year-old man who presented with acute right lower quadrant pain initially suggestive of acute appendicitis. However, computed tomography (CT) revealed a large infrarenal AAA with a contained rupture. This atypical presentation highlights the importance of including AAA in the differential diagnosis of elderly patients with abdominal pain. Early imaging, particularly CT, is essential to differentiate AAA from other causes of acute abdomen and to prevent diagnostic delays. Maintaining a high index of suspicion is critical for timely recognition and improved outcomes.