A ruptured giant mediastinal mature teratoma mimicking an encapsulated empyema.

A female patient with a right-sided encapsulated pleural effusion was misdiagnosed preoperatively as having an encapsulated empyema. However, a giant mass in the anterior mediastinum was found via thoracoscopy, and a mature teratoma was detected based on the pathological result. Herein we report this case and provide lessons for cardiothoracic surgeons.