A case of mediastinal pseudocyst with unusual cystic findings in computed tomography

: We report here a case of mediastinal pseudocyst with unusual CT findings. A 25-year-old woman was admitted to our hospital due to a chest abnormal shadow. She had a cystic mass which was located at anterior mediastinum and was adjacent to great vessels broadly without invasive findings. The intraoperative and histological findings revealed that the cystic mass was a pseudocyst which had been generated by the rupture of a thymic cyst to the mediastinum.