alpha-fetoprotein expression in a dedifferentiated liposarcoma.

Extremely rare cases of paraneoplastic syndromes or ectopic production of proteins associated with liposarcoma are reported in literature. We describe a unique case of relapsing retroperitoneal dedifferentiated liposarcoma with biochemical, immunohistochemical, and molecular evidence of alpha-fetoprotein (AFP) ectopic production. The lesion was associated to elevated AFP plasma levels that subsided after tumor removal. Immunohistochemical studies showed AFP production by a minority of tumor cells and reverse transcriptase polymerase chain reaction confirmed AFP mRNA expression. Finding of MDM2 and CDK4 iperexpression by immunohistochemistry confirmed the diagnosis of dedifferentiated liposarcoma.