The Superior Mesenteric Artery Syndrome (SMAS) is an unusual acquired clinical entity, produced by compression of the third duodenal portion by the superior mesenteric artery (SMA), resulting in duodenal obstruction. The incidence is not well known, as it is an under-diagnosed entity. Its clinical spectrum is wide and non specific, which makes it difficult to diagnose. We describe a patient, who consulted with pyloric syndrome. Gastrointestinal endoscopy revealed a lesion on the minor curvature, Bormann III type; it is also found a dilated second portion of the duodenum. We perform an upper gastrointestinal barium study, finding duodenal dilatation of the first and second portions and obstruction of the third. Double contrast abdominopelvic CT revealed duodenal obstruction caused by trapping of duodenal third portion between SMA and aorta. The diagnostic was SMAS, which was confirmed by sagittal reconstruction imaging which demonstrated the acute angle of branching of the SMA.