Benign Schwannoma of the Coronary Sinus in a Child: Diagnostic Pitfalls and Surgical Management

Primary cardiac tumors in children are uncommon, and cardiac schwannomas occur predominantly in adults. Benign coronary sinus schwannoma in a child represents an unusual presentation with important diagnostic and surgical considerations. We report the case of a 5-year-old child presenting with recurrent exudative pericarditis and signs of progressive heart failure. Initial evaluation suggested inflammatory pathology; however, advanced imaging revealed a mass originating from the coronary sinus. Surgical resection was performed via median sternotomy and cardiopulmonary bypass. Due to dense adhesions, the tumor was removed in fragments with radical excision. The coronary sinus was reconstructed using an autologous pericardial patch. Histopathology confirmed a benign schwannoma (S100 and SOX10 positive). The postoperative course was notable for transient right ventricular dysfunction, which resolved with supportive therapy. No tumor recurrence was observed during 48 months of follow-up. Coronary sinus schwannoma in children may mimic inflammatory pericardial disease. Timely surgical intervention with radical resection and anatomical reconstruction is feasible. This case highlights important diagnostic and surgical considerations in managing an unusual pediatric cardiac tumor.