BACKGROUND Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal gastrointestinal tumors (GIT). Usually, they appear in patients ages 55-65 years, with no apparent difference between males and females. Their annual incidence is about 11-14 per 10⁶. They generally do not present with any prominent symptoms, appearing with the atypical symptoms of abdominal pain, weight loss, early satiety, and occasionally bleeding. Adequate surgical treatment involves sphenoid resection of the tumor within clear margins. If adjacent organs are involved, en bloc resection is the procedure of choice. CASE REPORT A 62-year-old male patient presented to the Emergency Department complaining of melena for 1 week. He underwent gastroscopy, colonoscopy and abdominal computed tomography scan, which revealed a large, exophytic, lobular mass (12.6×9.7×12 cm) of the greater curvature of the stomach. The patient underwent en bloc sphenoid gastrectomy, splenectomy, and caudal pancreatectomy. The histopathologic examination revealed findings compatible with a gastrointestinal stromal tumor located at the stomach, with low-grade malignancy (G1) and T4N0 according to TNM classification. He was discharged from the hospital on the 7th postoperative day. CONCLUSIONS GISTs are uncommon tumors of the gastrointestinal system that usually do not invade neighboring organs or develop distant metastases; therefore, local resection is usually the treatment of choice. However, in cases of large GISTs that are adherent to neighboring organs, en bloc resection and resection of adjacent organs may be inevitable.