Huge Primary Pleural Cyst Mimicking an Exophytic Echinococcal Cyst: A Case Report

A 58-year-old woman presented with an incidental asymptomatic mass occupying the entire right lower thorax. A radiologic study demonstrated a huge cystic mass, initially suggestive of an exophytic echinococcal cyst. After unsuccessful catheter drainage, the patient was referred for surgery, and curative resection of the lung-, heart-, and diaphragm-compressing mass was performed under video-assisted thoracoscopic surgery. Culture studies revealed no growth of parasitic, bacterial, or fungal infections, and the final pathological result confirmed a primary pleural cyst. Thoracic cystic masses mostly manifest as bronchogenic or pericardial cysts, while primary pleural cysts have rarely been reported. We present a rare case of a huge pleural cyst that initially mimicked an echinococcal cyst.