Endoscopic ultrasound guided diagnosis of a retroperitoneal extra-gastrointestinal stromal tumor

GIST tumors are mesenchymal tumors that are usually positive for the CD-117 marker. They present mostly at middle ages of life and although the most frequent locations are the stomach, small intestine and rectum/colon, they can appear in unusual places such as the retroperitoneum. The case that we present reflects the diagnostic process with imaging tests such as echo-endoscopy with puncture, of a retroperitoneal GIST tumor.