Abstract
A 73-year-old female was admitted with an abnormal shadow on chest XP. Her chest CT showed the presence of a 3×3cm tumor with calcification in the left anterior mediastinum. Video-assisted thoracoscopic surgery was performed. The resected tumor measured 4.5×2.7cm, and it had a hard capsule due to calcification. This cystic tumor was filled with a soft brown tissue. Pathological examination revealed the presence of a mediastinal cyst of unknown origin because epithelial cells were not present on the inner surface of the cystic wall. Based on tumor localization and pathological findings, we suspected that this tumor was a thymic cyst with dystrophic calcification resulting from chronic inflammation.
