[A malignant fibrous histiocytoma of the breast]

We have experienced treating a 49-year-old female with a malignant fibrous histiocytoma (MFH) arising from the right mammary gland. Nine months after surgery, lung metastasis occurred but the lung lesion proved to be resectable. Our findings suggested that the primary lesion had originated from a phyllodes tumor. MFH arising from the mammary gland is an extremely rare tumor, and only 12 such cases have been reported including that of our patient.