Cystosarcoma phyllodes.

We present four cases of cystosarcoma phyllodes in which mammograms revealed a small or large lobulated mass occupying the entire breast. Preoperative diagnosis was a benign lesion with a low probability of nodular carcinoma. Histologically, all tumors were classified as malignant. Although uncommon, cystosarcoma should be considered in the differential diagnosis of these masses, since local recurrence is frequent unless wide wedge resection or simple mastectomy is done.