Breast phyllodes tumor (BPT),which is composed of epithelial cells and fibrous connective tissue,is a special type of tumor and yet not unified in biological behavior and histological classification,with high risk of recurrence and potential metastasis.BPT in one side has high incidence in clinic while BPT in both sides is rarely found.We treated one patient with giant BPT in both sides and reported as follows.1 Case reportThe patient,female,aged 49,was admitted due to a rapidly increased lump in the right breast in June 2010,and she complained that the lump had increased from the size of "an egg" to the size of "a basketball" in August and had then been treated as suspected inflammation with anti-inflammatory treatment before admission but failed.Physical examination on admission showed an about 35 cm× 32 cm ×33 cm huge lump in the right breast,firm and poorly-movable,with reddish purple and mildly warm epidermis,swollen but not ulcerated (Fig.1).