Postoperative chylous leak is often a consequence of thoracic duct injury during surgical procedures. Persistent chylothorax can be an extremely morbid condition. The authors describe a case of a refractory and long-standing chylous leak after thoracotomy for mediastinal lymphangioma removal. The patient was treated with a computed tomography-guided percutaneous thoracic duct sclero-embolization after failure of the conventional therapies. The chest tube output abruptly decreased after the procedure and was removed at 13th day. Percutaneous thoracic duct sclero-embolization proved to be safe and effective in the treatment of a persistent chylothorax.