A Case of Pancreaticoduodenectomy following Endoscopic Mucosal Resection for a Neuroendocrine Tumor in the Horizontal Portion of the Duodenum

Abstract

A 48-year-old man was found to have a 12-mm pedunculated submucosal tumor in the horizontal portion of the duodenum during a routine medical checkup. Endoscopic mucosal resection (EMR) was performed for diagnostic and therapeutic purposes, and the lesion was completely removed. Histopathological examination revealed a neuroendocrine tumor (NET) G1. Owing to lymphatic invasion, the patient was referred to our department. A pancreaticoduodenectomy was performed for additional resection with lymph node dissection. No residual tumor or lymph node metastasis was observed. EMR is recommended for duodenal neuroendocrine neoplasms (NENs) that are ≤10 mm and invade up to the submucosa. In this case, a preoperative diagnosis could not be established, and the pedunculated morphology led to the initial choice of endoscopic treatment. Pancreaticoduodenectomy was selected considering the extent of the lymph node dissection. Non-ampullary duodenal NENs are extremely rare, and no established consensus exists regarding the treatment strategies or predictive factors for lymph node metastasis. Further accumulation of cases is needed to clarify optimal management.