A case of carcinosarcoma of the breast.

Carcinosarcoma is a rare malignant tumor of the breast. A 59-year-old woman was admitted to our hospital with a complaint of a right breast mass for one month. The mass grew rapidly, and modified radical mastectomy was performed. Based on the histological findings of carcinomatous and sarcomatous components entangled without a transition area, and the results of immunohistochemical staining, carcinosarcoma of the breast was diagnosed. Within 9 months of the surgery, a recurrent lesion appeared in her chest wall. As shown by local resection, this recurrent tumor had only a carcinomatous component. Such tumors are very rare, and there have been no detailed reports of recurrence patterns of carcinosarcoma. Here we report our pathological findings in detail.