Thymoma with ossification ; a case report

A rare case of thymoma with multiple ossifications is reported. A 27-year-old male was found to have a tumor shadow in the left anterior mediastinum on a routine chest X-ray. Despite marked calcification of the tumor shadow, it was difficult to diagnose preoperatively. The tumor was resected on January 29, 1993 for diagnosis and dicision about theraphy. Histological examination revealed that the tumor was an invasive thymoma, epithelial cell dominant type with multiple ossifications. His post operative course was uneventful. No recurrence has been observed during the 12 months since the operation. In this case, it was difficult to differentiate this tumor from teratoma because of the intense calcification. We consider that the ossification in this tumor may represent an osteoplastic reaction to metaplastic calcification.