A 57-year-old woman with von Recklinghausen's disease presented with epigastralgia. Gastroduodenoscopy revealed swelling of the ampulla of Vater in the ventral and caudal direction, forming a hard, elastic mass. She was diagnosed with a tumor of the ampulla of Vater, and a subtotal stomach-preserving pancreaticoduodenectomy and D2 lymph node dissection were performed. The isolated specimen showed an intra-ampullary tumor of the ampulla of Vater and a submucosal tumor in the descending duodenum, which were diagnosed as a somatostatin-producing neuroendocrine tumor and gastrointestinal stromal tumor, respectively, on pathological examination. We believe that the neuroendocrine tumor of the ampulla of Vater and gastrointestinal stromal tumor of the duodenum are common gastrointestinal lesions in von Recklinghausen's disease.