Pulmonary metastatic gastric cancer mimicking a giant mediastinal cyst

Cysts and cavities are common radiologic abnormalities. Pulmonary metastasis comprises a rare entity of thoracic cystic diseases. We reported a case of giant cyst at the left anterior mediastinum that was pathologically confirmed as a lung metastasis from previously resected gastric cancer. The cyst was completely removed with wedge resection of the surrounding lung through a left anterior thoracotomy. One should always keep in mind the possibility of an intrathoracic cyst near or at the mediastinal region that may originate from metastatic lesions to the lungs when patients have previous cancer history.