Extra-Gastrointestinal Stromal Tumor (EGIST) in the Pelvis Mimicking Retroperitoneal Sarcoma.

Extra-gastrointestinal stromal tumors (EGISTs) are rare mesenchymal tumors accounting for less than 1% of total gastrointestinal tumors. They tend to be aggressive and have a poor prognosis. Unfortunately, there is a lack of data or controversial data due to its scarcity.