Phyllodes tumor (cystosarcoma phyllodes) is a nonepithelial breast tumor that may be benign or malignant.

Tumors are frequently large (4 to 5 cm) at diagnosis. About half are malignant, accounting for < 1% of breast cancers. Between 20% and 35% of these tumors recur locally, and distant metastases occur in 10 to 20% of patients.

Usual treatment is wide excision, but a mastectomy may be more appropriate if the mass is large or histology suggests cancer. Prognosis is good unless metastases are present.

Last full review/revision November 2008 by Victor G. Vogel, MD, MHS