Left Upper Extremity Pain, Right Coronary Artery Culprit: A Puzzling Path to Aneurysm Discovery.

Giant coronary artery aneurysm (GCA) is a rare disease afflicting 0.2% of the population. It is primarily attributed to atherosclerosis in adults and Kawasaki disease in children. Other uncommon etiologies include Takayasu arteritis and post-percutaneous coronary intervention. 1,2 GCA lacks a universally accepted definition, with proposed criteria including a diameter exceeding 2 cm, 5 cm, or four times the normal vessel size. 3 While the majority of GCAs are asymptomatic, a subset of patients present with angina, myocardial infarction from embolization or compression, heart failure due to fistula formation, or even sudden death. 1 We report a case of an adult harboring a GCA involving the right coronary artery.