Gastrointestinal stromal tumors (GISTs) are rare neoplasms arising from connective tissue elements of the gastrointestinal wall. They show a great heterogeneity with respect to their histogenetic, morphologic and prognostic characteristics. GISTs are known with myoid, neural or mixed features of differentiation. Clinical findings are gastrointestinal bleeding, abdominal pain and weight loss. We report on the case of a 50-year-old male patient who presented with melena and acute anemia (hemoglobin 10.5 g/dl). Esophagogastroduodenoscopy revealed a broad-based, centrally ulcerated polypoid formation of 3 cm in the gastric corpus as the cause of the upper gastrointestinal bleeding. Multiple endoscopic biopsies were negative for neoplastic changes. Because of no tendency of healing after triple eradication therapy of Helicobacter pylori and following proton pump inhibitor medication, the patient underwent distal gastrectomy with gastrojejunostomy. GIST of combined smooth muscle and neural type was diagnosed by histological and immunohistochemical examination. The features with increased mitotic activity and cellularity were those of a borderline stromal tumor. 6 months after surgery the patient is well with no signs of residual malignancy. This case demonstrates that rare stromal neoplasms have to be taken into account in the differential diagnosis of gastrointestinal tumors even if endoscopic biopsies are negative for neoplastic changes. Because of the uncertain biological behavior of the GISTs an early surgical intervention is recommended.