A case of multiple type I endocrine neoplasia with gastrin-producing and glucagon-producing tumors successfully resected 18 years after insulinoma surgery.

Pancreatic neuroendocrine tumors (NETs) are common manifestations of multiple endocrine neoplasia type 1 (MEN1), whereas functional tumors such as gastrin-producing tumors are less frequent. Although gastrinomas associated with MEN1 have a high level of biological malignancy, they are considered fully treatable with surgical resection based on accurate localization. We report the case of a 27-year-old woman with MEN1 who had a gastrin-producing tumor and a glucagon-producing tumor removed 18 years after surgery for insulinoma. She had an increased gastrin concentration, and abdominal ultrasound and magnetic resonance imaging revealed an 18-mm tumor in the pancreatic tail. A selective arterial calcium injection test was positive for the gastroduodenal artery, but negative for the splenic artery. Therefore, we judged that the feeding artery for the gastrin-producing tumor was the gastroduodenal artery. Distal pancreatectomy and pancreaticoduodenectomy were performed. The resected specimen revealed 15 micro-gastrin-producing tumors measuring ≤ 5 mm, and six lymph node metastases in the duodenum and pancreatic head. The pancreatic tail tumor was a glucagon-producing tumor. In this case, long-term postoperative follow-up and accurate local diagnosis, including selective arterial calcium injection testing for gastrin-producing tumors, resulted in successful curative resection. It is important to keep in mind that various hormone-secreting tumors may occur simultaneously or metachronously in patients with MEN1.