Retro-rectal tumors are a very rare entity in the adult population, with an incidence of approximately 1 in every 40.000-63.000 patients. Gastrointestinal Stromal Tumors (GIST) are the most common mesenchymal tumors of the gastrointestinal tract.Clinical Case: 51-years-old patient with a clinical scenario of dysuria, vesical urgency and tenesmus, urinary retention, and constipation. Computer Tomography (CT) and Magnetic Resonance Imaging (MRI) shows a presacral mass. Pathology studies report GIST. Treated with abdominal resection and adjuvant therapy.Discussion: In 1983 the GIST was described with its origin in interstitial cells of Cajal, this tumor is more frequently found in the stomach, appearing in the 4 th decade of life and being abdominal pain the most common symptom, the more used diagnostic tools are still the CT and MRI, they let the physician decide which of the three approaching surgical methods is used. There are 3 histologic types GIST and the stratification of risk for each one is given based on tumor site, size, number of mitosis, and rupture.