Cystosarcoma phyllodes of the breast.

Cystosarcoma phyllodes is a rare breast lesion representing between 0.5 and 2.5 percent of all breast tumors. Its microscopic and clinical features are impressive. When first described by J. Mueller in 1838, the lesion was thought to be a benign neoplasm without metastatic potential. Nevertheless, more recent reports have shown either recurrent or metastatic cystosarcoma phyllodes. Some Authors have attempted to predict biologic behavior from histological appearance so that the extent of surgical management could be determined. However, only a small percentage of histologically malignant tumors have recurred or metastasized. The above observations stimulated the present analysis of the histology, clinical behavior, appropriate therapy and prognosis in ten patients with cystosarcoma phyllodes seen at our unit, from 1965 to 1979.