Delayed High-Output Chylothorax Following Thymectomy for Thymoma

Chylothorax is an uncommon complication following thymectomy and results from disruption of the thoracic duct or its tributaries during surgery. We report the case of a 50-year-old man with autoimmune myasthenia gravis who developed a delayed postoperative chylothorax following video-assisted thoracoscopic surgery (VATS) thymectomy for a type B2 thymoma, Masaoka stage I. On postoperative day 21, the patient presented with acute respiratory distress and severe hypoxemia. Chest computed tomography revealed a large left-sided pleural effusion with extensive passive lung collapse. Thoracentesis in the emergency department evacuated 1.5 L of milky pleural fluid, followed by an additional 4 L after chest tube drainage in the intensive care unit. Pleural fluid analysis revealed a triglyceride concentration of 188 mg/dL, with chylomicrons detected, confirming the diagnosis of chylothorax. The fluid also showed marked lymphocytic predominance (96%). Management included pleural drainage, a strict fat-free diet, and octreotide, administered as a 100 µg slow intravenous loading dose followed by continuous infusion at 50 µg/h. Pleural drainage showed an overall decreasing trend and eventually ceased. Octreotide was discontinued after 13 calendar days, and the chest tube was removed without requiring additional invasive or surgical intervention. The patient was subsequently discharged home. This case illustrates that post-thymectomy chylothorax may present several weeks after surgery and that conservative management may achieve a favorable outcome even in the setting of substantial initial pleural drainage.