[Successful surgical treatment for giant non-specific cyst in the anterior mediastinum].

A 46-year-old woman was admitted to our hospital with giant cyst in the anterior mediastinum. We strongly suspected the cyst would be cystic teratoma from preoperative examinations. Cystectomy was undergone through a right thoracotomy in the 6th intercostal space. The cyst, 15 x 14 x 13 cm in size, had a fibrous wall and contained yellowish serous fluid with hair-ball which revealed aseptic bacteriologically. In the pathological study, the cyst had no recognizable specific epithelium or mesothelium, and this finding was incompatible with cystic teratoma. Due to lack of teratoid elements, the final diagnosis was "non-specific mediastinal cyst". The cyst was considered to be the result of inflammation or intracystic auto-digestion by enzymes from the alimentary tissue of the cystic teratoma.