A case of thymic basaloid carcinoma with rectal carcinoma.

Abstract Introduction Thymic basaloid carcinoma is rare, as only about 40 reports have described it since the initial report. Thymoma and thymic carcinomas increase the risk of other malignancies, but concurrent thymic basaloid carcinoma and another malignancy has not been reported. We presented a rare case of thymic basaloid carcinoma with rectal carcinoma. Case presentation Computed tomography revealed an anterior mediastinal mass and rectal wall thickening, and colonoscopy identified a rectal type 2 tumor in a 68-year-old man. Total thymectomy via a median sternotomy was performed, and the thymic tumor was histopathologically confirmed as stage II thymic basaloid carcinoma. Subsequent laparoscopic low anterior resection indicated stage IIIa rectal carcinoma. Adjuvant chemotherapy was administered for the rectal cancer. Discussion Concurrent thymic and extrathymic tumors is rare condition. There are few reports of thymic basaloid carcinoma, and it is unclear whether this tumor, like common thymoma, increase the risk of extrathymic malignancies. Further studies in more patients are needed to elucidate the nature of this tumor. Conclusion To our knowledge, this is the first case report of thymic basaloid carcinoma concurrent another carcinoma. Aggressive treatment including surgery should be considered aiming at radical cure.