Abstract
BACKGROUND: Thymic carcinoma is prone to early metastasis and invasion, while its metastasis to the breast is particularly unique. CASE REPORT: We describe a case of thymic epithelial tumor metastatic to the breast fulfilling clinical diagnostic criteria. A 47-year-old female patient diagnosed with stage IV thymic carcinoma and previously treated with chemoradiation was diagnosed with metastatic breast cancer during a periodic review. Color Doppler ultrasonography showed a low-echo real occupancy in the breast. Pathological examination of the breast mass confirmed the diagnosis of thymic carcinoma metastasis. CONCLUSION: Hematogenous metastasis of thymic carcinoma to the breast is rare but not exceptional, and long-term survival can be expected with appropriate treatment.