Dedifferentiated liposarcoma masquerading as a recurrent inflammatory pseudotumor

Liposarcoma is a heterogeneous cancer that typically presents at an advanced stage, which leads to a poor prognosis, especially when it is located in the retroperitoneum. Although there are plenty of treatment strategies for liposarcoma, surgery is currently the primary therapeutic choice. Several cases of dedifferentiated liposarcomas that were masquerading as inflammatory pseudotumor have been previously reported, and this contributes to the diagnostic challenge. Many studies have suggested that inflammatory pseudotumor is a type of neoplasm or cancerous process. The use of immunostaining and genetic testing would be very helpful for making a correct diagnosis. Here we present the case of a recurrent tumor located in the retroperitoneum. The patient was initially diagnosed with an inflammatory pseudotumor and then a dedifferentiated liposarcoma following their second presentation.