[A Case of Neuroendocrine Tumor of the Second Part of the Duodenum].

A 69-year-old woman was referred to our hospital when the upper gastrointestinal endoscopy performed by the previous physician for detailed examination of upper abdominal discomfort indicated a duodenal tumor. Upper gastrointestinal endoscopy revealed a submucosal tumor with a central depression in the descending part of the duodenum. Contrast- enhanced computed tomography of the abdomen revealed a 23 mm tumor with contrast effect in the descending part of the duodenum contralateral to the Vater papilla. There was no lymphadenopathy or distant metastasis. Duodenal gastrointestinal stromal tumor was suspected, and localized duodenectomy was planned. Intraoperative findings showed that the tumor was located in the descending part contralateral to the Vater papilla with no evidence of surrounding invasion. Localized duodenectomy was performed, and on intraoperative rapid histopathological examination, an adenocarcinoma was suspected. As a result, the surgery was changed into pancreaticoduodenectomy. Based on the results of immunostaining, neuroendocrine tumor grade 2 was diagnosed. No lymph node metastasis was observed. The patient did not have recurrence of lesion 7 months after surgery.