化生性胸腺腫の1例

Metaplastic Thymoma；Report of a Case

はじめに　化生性胸腺腫（metaplastic thymoma）は多角細胞成分と紡錘形細胞成分の二相性を示すまれな胸腺上皮性腫瘍である．われわれはmetaplastic thymomaの1例を経験したので，若干の文献的考察を加え報告する．

A 76-year-old man was referred to our division because of an abnormal shadow on chest computed tomography （CT）. CT revealed a 20 mm nodule in the anterior mediastinum. Non-ivasive thymoma was suspected and thymomectomy and resection of right thymus was performed.

The resected tumor was 25×25×13 mm in size. Pathologically the tumor was composed with polygonal cell components and spindle cell components, partially invading surrounding tissue. Cytokeratin AE1/3 and epithelial membrane antigen （EMA） were strongly positive, and the pathological diagnosis was biphasic, metaplastic thymoma.