Giant pericardial cyst with coronary artery involvement: a rare case of progressive right heart compression in an infant

Pericardial cysts are rare, benign congenital cardiovascular malformations that account for approximately 7% of mediastinal masses. Epicardial cysts attached to the cardiac surface with intimate coronary artery involvement are even rarer and pose significant diagnostic and surgical challenges. This case highlights a giant pericardial cyst with intimate right coronary artery involvement in a 10-month-old infant, where subtotal resection was necessary to preserve coronary integrity. A 10-month-old male infant with a pericardial cyst initially detected at 27 weeks of gestation presented with progressive compression of right heart chambers. Imaging revealed a large multiloculated cystic mass (5.3 × 3.5 × 3.9 cm) compressing the right atrium and right ventricle, with associated pulmonary valve stenosis. Intraoperatively, the cyst was found on the epicardial surface with intimate involvement of the right coronary artery. Complete excision was not feasible due to the risk of coronary injury. The main cystic mass was excised with cavity obliteration, while the portion adjacent to the right coronary artery was intentionally preserved. Concurrent pulmonary valve commissurotomy and pulmonary artery augmentation were performed. Histopathology confirmed a mesothelial-lined pericardial cyst. The patient recovered uneventfully and was discharged. This case underscores the importance of comprehensive preoperative coronary artery assessment in pericardial cysts with atypical locations. When complete excision risks vital structure injury, subtotal resection with cavity obliteration represents a safe alternative strategy.