Malignant tumors of the breast arising from the connective tissue of the gland are rare and underestimated. Three new cases are here reported: 1 malignant fibrous histiocytoma and 2 malignant phylloides tumors. Tumor size, mammographic findings and cytologic aspect of the needlebiopsy lead to the correct diagnosis. Large excision or radical mastectomy are treatments of choice, while axillary lymph nodes dissection does not appear justified, since metastatic spread via lymphatics is rare. Postoperative radiation and chemotherapy seem not effective in preventing local recurrences.