[A case of metastatic gastric cancer secondary to pancreatic neuroendocrine tumor fifteen years after distal pancreatectomy].

A 56-year-old man underwent distal pancreatectomy in July 1997, and chemotherapy was administered as adjuvant therapy. The histopathological diagnosis was a neuroendocrine tumor of the pancreas, NET G2 (Ki-67 labeling index: 3%), T2N0M0 stage IB, according to the TNM classification. In July 2011, follow-up endoscopic examination showed a submucosal tumor covered with almost normal gastric mucosa in the posterior wall of the upper stomach. Endoscopic ultrasound showed a heterogeneous-echoic submucosal tumor present at both the submucosal layer and the proper muscle layer. Abdominal enhanced CT revealed a 3-cm-diameter enhanced mass in the posterior wall of the upper stomach. We performed local resection of the gastric posterior wall. The histopathological diagnosis was a metastatic gastric tumor secondary to a pancreatic endocrine tumor, NET G2 (Ki-67 labeling index: 10%). In this paper, we report a rare case of metastatic gastric cancer secondary to a pancreatic neuroendocrine tumor 15 years after the first operation, together with a review of the literature.