Endobronchial ultrasonography in a patient with a mediastinal thoracic duct cyst

Mediastinal thoracic duct cysts are rare clinical findings. We report the case of a symptomatic 58-year-old woman in whom a thoracic duct cyst was successfully treated with surgical resection. Preoperative endobronchial ultrasonography revealed an oval-shaped hypoechoic area with a distinct, thick pedicle, gradual intermittent flux of the fluid content within the lesion, and endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) revealed lymphocyte predominant serous fluid without malignancy, which is consistent with features of a mediastinal thoracic duct cyst. We postulate that EBUS-TBNA can be used as a preoperative diagnostic tool for patients with possible mediastinal thoracic duct cysts.