Malignant phyllodes tumor of the breast with liposarcomatous differentiation and intraductal hyperplasia.

Phyllodes tumor of the breast is a biphasic fibroepithelial neoplasm. 10 to 20% of phyllodes tumor show malignant transformation, often in the form of stroma, which usually shows fibrosarcomatous differentiation and rarely heterologous sarcomatous elements. Liposarcomatous differentiation is not common among phyllodes tumors. The correct diagnosis of heterologous liposarcomatous differentiation in a malignant PT requires identification of the biphasic component of the tumor. We reported a case of malignant phyllodes tumor which initially transformed into liposarcoma, in addition to a very rare intraductal hyperplasia and flat epithelial atypia. The patient was a 75-year-old woman, with a lump in the left breast without axillary lymphadenopathy. She also have a positive family history of breast carcinoma. She underwent surgery and still alive and disease free after one year.