Primary Giant Mediastinal Hydatid Cyst Extending to the Superior Thoracic Inlet.

A 57-year-old woman presented to our hospital with chest and shoulder pain. A giant mediastinal cystic lesion extending from the apex to the inferior perihilar area on the right hemithorax was detected radiologically. The patient underwent video-assisted thoracoscopic surgery. The intraoperative lesion was identified as a hydatid cyst and resected thoracoscopically (Figure 1).

FIGURE 1:

(A) Axial, (B, C) coronal, and (D) sagittal thoracic computed tomography sections show a mediastinal cystic lesion of approximately 10 x 4 cm (arrowheads) extending from the apex to the perihilar area in the right hemithorax. (E, F) The lesion was diagnosed intraoperatively as a hydatid cyst (arrow, laminated membrane; circle, cyst cavity).

Hydatid cysts caused by metacestode forms of Echinococcus granulosus are commonly located in the liver and lungs. The mediastinal involvement rate is 0.61%, and primary mediastinal localization is less common . Symptoms depend on the cyst size, location, and compression on adjacent structures, such as the esophagus, aorta, trachea, vena cava, and phrenic nerve , . Although primary giant mediastinal hydatid cysts are rare, they should be considered in the differential diagnosis of all mediastinal lesions.