Parenchyma-Sparing Subtotal Thymectomy for a 5-Week-Old Infant With Giant Multilocular Thymic Cyst

We report a rare case of a 5-week-old male infant presenting with progressive respiratory distress due to a giant multilocular thymic cyst. Emergency subtotal thymectomy was performed, with deliberate preservation of thymic parenchyma that appeared grossly normal. The patient had an uneventful postoperative recovery, and no recurrence was observed at 1-month and 6-month postoperative follow-up assessments. This case highlights the feasibility and potential benefits of thymic parenchyma preservation in infants, offering a surgical strategy that balances effective mass resection with immune function preservation.