The existence and value of estrogen and progesterone receptors in cystosarcoma phylloides Ten cases of cystosarcoma phylloides diagnosed at Ankara Numune Hospital were reviewed. Our purpose was to evaluate the value of estrogen and progesterone receptors. Analysis of these 10 cases revealed 5 benign lesions, 2 malignant tumors and 3 borderline lesions. Estrogen in ductus epithelial cell nucleus was positive in 5 cases (50%). Also progesterone was positive in stromal cell nucleus in 3 cases (30%). There was no death, no recurrence and no metastasis although the control time is 35.2 (15-58) months. In addition, receptor presence suggests that hormonal manipulation may warrant consideration as an adjuvant treatment.