Incidentally found, growing congenital aneurysm of the left atrium.

A left atrial aneurysm is a very rare cardiac anomaly that usually develops in the left atrial appendage. It usually develops congenitally, and has a risk of life-threatening complications. Here, we report a case of a growing aneurysm of the left atrium that was incidentally found in a 42-yr-old woman. Eighteen years prior, an abnormal cardiomegaly was found on a chest radiography for a pre-operative study. The chest radiography at this time demonstrated a more prominent cardiomegaly than the previous radiography findings. The left atrial aneurysm was diagnosed by echocardiography and cardiac catheterization. Although asymptomatic, she underwent a successful surgical excision to allay the possibilities of rupture, arrhythmia, heart failure, or thromboembolism. The surgical findings demonstrated an 8 x 15 cm sized saccular aneurysm at the left atrial appendage, and the pathologic findings showed three myocardial layers. The patient has been asymptomatic during the 15 months of follow-up. In conclusion, a congenital left atrial aneurysm can grow with time, even in asymptomatic cases, and an aneurysmectomy is a curative treatment, which can eliminate the potential complications.