Primary dedifferentiated liposarcoma of the axilla arising in a mixed, well-differentiated and myxoid liposarcoma.

[dedifferentiated liposarcoma]

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 .