Congenital left main coronary artery aneurysm.

Left main coronary artery aneurysm (LMCAA) is an uncommon coronary abnormality seen in 0.1% of patients during routine diagnostic coronary angiographies. The most common etiology is atherosclerosis in acquired cases. However, it can also be a congenital malformation. We present the case of a 26 year-old female with a large LMCAA. She was diagnosed with tetralogy of Fallot initially.