Abstract
A 72-year-old woman was admitted to our hospital for further examination of abnormal shadow on chest X-ray. Chest CT showed a mediastinal cyst with tumorous portion. Venography showed that the left brachiocephalic vein was coursed around the cyst and into the lower part of superior vena cava. Thallium scintigraphy showed a positive sign on the tumorous portion. The tumor was resected and was found to be composed thymic cyst with thymic cancer. This case suggests that malignant tumor can arise from a benign thymic cyst.
