Abstract
Retroperitoneal lipomas are extremely rare with few cases reported so far in the literature. They can reach different sizes and present with a variety of symptoms. The differential diagnosis is mainly with well-differentiated liposarcoma (WDLPS). We present a 34-year-old woman with a retroperitoneal lipoma herniating through the inguinal canal into the proximal thigh. The patient underwent complete oncological resection using a Karakousis's abdominoinguinal incision. Retroperitoneal lipomas are a very rare condition and sometimes require resections technically challenging. MDM2 amplification is critical for its differential diagnosis with WDLPS.