Atypical lipoma: well-differentiated liposarcoma of the orbit with dedifferentiated areas.

Primary orbital liposarcoma is a very rare orbital tumor and dedifferentiation in the liposarcomas occurs rarely. Dedifferentiation is defined by development, in a well-differentiated tumor, of poorly differentiated, high-grade areas. The dedifferentiated liposarcomas (DDLS) have a better prognosis than pleomorphic sarcomas as a whole. The treatment of DDLS patients proves to be complicated due to the fact that the histopathological diagnosis usually becomes evident only after the surgery. In the present paper, the clinical presentation, histopathological features, radiological characteristics and clinical treatment of one case of well-differentiated liposarcoma with dedifferentiated areas, abruptly delimited from the well-differentiated adipocytic component, are reported.