ABSTRACT
We report a rare case of dedifferentiated liposarcoma in a man. A 60-year-old male patient presented with a left mass involving the whole breast area, with no lymph node enlargement, growing during a one-year-period. Imaging studies revealed a fat-containing mixed-density mass apparently associated with the pectoralis major muscle. A core biopsy was performed that yielded a diagnosis of a well-differentiated liposarcoma. Further tests to check for metastases were ordered and no distant disease was found. Left mastectomy with en bloc resection of the pectoralis major muscle was performed. The pathologic diagnosis revealed a high-grade dedifferentiated liposarcoma with extensive necrosis. This tumor type is primarily described in the retroperitoneum and extremities. We report an unusual presentation of a liposarcoma mimicking a breast mass.