• Thirty-five cases of benign cystosarcoma phyllodes, 13 cases of malignant cystosarcoma phyllodes, and ten cases of giant fibroadenoma were studied. The diagnosis of benign or malignant cystosarcoma phyllodes was based on a combination of histological features. Clinical and gross pathologic findings were not found to be useful in distinguishing between benign and malignant tumors. Giant fibroadenomas occurred primarily in black adolescents and were histologically distinct. Positive surgical margins were found to be the best predictor of local recurrence of benign or malignant cystosarcoma phyllodes. Systemic metastases occurred in only one case of malignant cystosarcoma phyllodes. Most benign and malignant cystosarcoma phyllodes may be treated by wide local excision with tumor-free margins. Giant fibroadenomas should be treated by simple excision to preserve normal breast tissue.
(Arch Surg 1988;123:1079-1083)