Thymoma with osseous metaplasia.

A 69-year-old woman with a 15-year history of abnormal chest shadow was referred to our hospital. An enhanced chest CT scan of the anterior mediastinum revealed a mass containing a high-density area. The preoperative radiologic diagnosis was thymoma. Operation was performed in October 2000. Histologically, multiple ossified areas were observed within the tumor. Intratumoral ossification has never been reported in thymoma. Therefore, we report the first case of thymoma associated with multiple foci of osseous metaplasia.