Malignant Phyllodes Tumor of the Breast with Liposarcomatous Differentiation, A Rare Case

ABSTRACT
Phyllodes tumors are rare fibroepithelial neoplasms and comprise less than 1% of all breast tumors. Heterologous sarcomatous differentiation is rarely observed in phyllodes tumors and in this study, a case of phyllodes tumor containing heterologous liposarcoma component is presented. A rapidly expanding mass in the left breast of an 86-year-old woman led to her admission to the general surgery outpatient clinic. A BI-RADS 4 nodular lesion was detected in the mammographic examination and was evaluated as suspicious for phyllodes tumor. Left modified radical mastectomy material was sent to our laboratory. Macroscopic examination revealed a nodular mass measuring 9.5x9x8 cm with focal infiltrative borders in breast tissue sections. In histological sections, the tumoral lesion was noted to have hypercellular, pleomorphic stroma and in some places the typical leaf-like architecture of phyllodes tumor. A well-differentiated liposarcoma component was observed in the tumor, containing lipoblast-like cells with single and multiple vacuoles, clear cytoplasm, and hyperchromatic nuclei. In the light of all the findings, the case was reported as malignant phyllodes tumor containing heterologous liposarcoma component. Phyllodes tumors showing heterologous sarcomatous differentiation are quite rare and when sarcomatous neoplasia is seen in the breast, phyllodes tumor ought to be taken into account while making a differential diagnosis. In order to distinguish phyllodes tumor with sarcomatous differentiation from primary breast sarcomas, it is very important to show the benign epithelial component of the tumor by taking multiple samples.
Keywords: Phyllodes tumor, breast, liposarcoma