The incidence of phylloides breast tumors is less than 1% in the population affected by breast cancers. The age at higher risk is between 35 and 45 years. These neoplasms are characterized by a proliferation of mesenchimal and epithelial cells. We present a rare case of giant malignant phylloides tumor (28 x 21 x 15 cm) with a complet substitution of the gland. The clinical presentation of phylloides tumors is heterogenous; the surgical treatment is a conservative one of the gland if the neoplastic lesion size is less than 5 cm with a free margin of 1 cm and a mastectomy if the diameter of lesion is more than 5 cm. Complementary therapies still remain controversial.