Abstract
A 74-year-old woman was referred to our department for evaluation of a diverticulum and a submucosal nodular lesion around the Vater papilla, which was detected at the time of complete medical checkup. Upper gastrointestinal panendoscopy showed a brownish nodular lesion with central depression ; however, the biopsy specimen showed no evidence of malignancy. Endoscopic ultrasonography showed a mildly hypoechoic or isoechoic mass that arose from the second and third layers of the duodenal wall. The second biopsy specimen showed a neuroendocrine tumor. Under the diagnosis of neuroendocrine tumor of the accessory papilla of the duodenum, the lesion was removed by subtotal stomach preserving pancreatoduodenectomy. Postoperative pathological analysis showed a neuroendocrine tumor in the accessory papilla of the duodenum (size, 10×8 mm). There was no definitive lymph node metastasis. The tumor, evaluated using Ki-67 and the mitotic index, was graded as WHO-G1. Neuroendocrine tumors of the accessory papilla of the duodenum are very rarely detected and are usually small. Endoscopy performed at the time of health check-ups is important for detecting such tumors. Radical surgery is usually recommended because they appear to have aggressive biological behavior, irrespective of the small size.
