A rare case of left atrial appendage aneurysm.

Background: Left atrial appendage aneurysm is a rare cardiac mass, with only a few cases reported. There are usually no specific symptoms, and a few patients visit the doctor with symptoms.

Case Presentation: A 20-year-old male presented to our hospital with a "pericardial cyst found by medical evaluation in another hospital for 2 years." Cardiac ultrasound performed at clinics of our hospital suggested a cystic dark area in the left ventricular lateral wall and the anterior lateral wall, consistent with a pericardial cyst and mild mitral regurgitation. After further relevant examinations and ruling out contraindications, an excision of the left atrial appendage aneurysm was performed under general anesthesia and cardiopulmonary bypass with beating-heart. The postoperative pathological results identified that: (left atrial appendage) fibrocystic wall-like tissue with a focal lining of the flat epithelium, consistent with a benign cyst.

Conclusion: Left atrial appendage aneurysms are rare and insidious. They are usually found by chance during medical evaluations. If the location is not good or the volume is too large, then compression symptoms or arrhythmia, thrombosis and other concomitant symptoms will occur. Surgical resection is presently the only effective radical cure for a left atrial appendage aneurysm.