Primary Dedifferentiated Liposarcoma of the Axilla Arising in a Mixed, Well-differentiated and Myxoid Liposarcoma

Abstract

We describe a case of mixed liposarcoma of the axilla presenting as a high grade undifferentiated sarcoma with areas of well-differentiated and myxoid liposarcoma.  MRI demonstrated a lobulated, septated intermuscular mass with marked heterogeneous gadolinium enhancement.  A small focus of the tumor demonstrated fat suppressed signal more characteristic of well-differentiated liposarcoma.  Pathologic analysis following wide local excision revealed a large, high grade sarcomatous component with highly pleomorphic cells with a thin rim of well-differentiated and myxoid liposarcoma on histologic examination.  Dedifferentiated liposarcomas arising outside of the retroperitoneum are very rare, as are dedifferentiated liposarcomas arising from a histologically mixed liposarcoma.   In this regard, this case illustrates an unusual combination of tumor location and histology which, to our knowledge, has not previously been reported.