Introduction : Cystosarcoma phyllodes of the breast are rare, and it accounts for less than 1% of the malignant tumors of the breast. Its clinical and radiological characteristics are those of benign tumors, and only a fast tumoral growth can evoke diagnosis. Materials and methods :We report five cases of cystosarcoma phyllodes of the breast and review the literature to report the circumstances of occurrence of these tumors, their specific difficulties in clinical diagnosis, and therapy.Results : The average age of our patients was 34.9 years. Eighty percent had two parity or more, except a nulliparous unmarried patient. The size of the tumor was on average 8 cm, with localization especially on the left breast (75%). The imagery showed an aspect favoring benignity. Fine needle aspiration cytology evoked the presence of phyllodes tumors or fibroadenomas. In all the cases, the surgical treatment consisted of a radical mastectomy. One patient underwent a lymph node clearing out because of the presence of axillary adenopathy and treatment was completed by radiotherapy. The follow-up showed a locoregional and systemic control in all our patients between six months and eight years. No death is to be regretted in our study.Epidemiologic factors, diagnosis and therapeutic difficulties will be discused using our experience and literature review.