Question: A 28-year-old man was admitted for postprandial epigastric pain, and chronic vomiting for 6 months, associated with a 6-kg weight loss. He had no relevant medical or family history. Physical examination and laboratory workup were normal. An anechoic lesion located in the second part of the duodenum wall was revealed on abdominal ultrasound imaging, and a submucosal mass was diagnosed in the same region, using an upper endoscopy technique. Furthermore, endoscopic ultrasound imaging and magnetic resonance imaging with dynamic sequences showed a 25 × 26-mm cystic duodenal lesion.