Primary lymph node gastrinoma. A diagnosis of exclusion. A case for duodenotomy in the setting of a negative imaging for primary tumor: A case report and review of the literature

INTRODUCTION: Zollinger–Ellison syndrome (ZES) is caused by uninhibited secretion of gastrin from a gastrinoma. Gastrinomas most commonly arise within the wall of the duodenum followed by the pancreas. Primary lymph node gastrinomas have also been reported in the literature. This is a case of ZES where preoperative localization revealed a gastrinoma in a solitary portacaval lymph node, presumed to be a primary lymph node gastrinoma. PRESENTATION OF CASE: The patient is a 57 year old female diagnosed with ZES, suspected of having a primary lymph node gastrinoma. The patient underwent an exploratory laparotomy and excision of a portacaval lymph node with a frozen section which was positive for gastrinoma. Intraoperative sonography of the pancreas, upper endoscopy with transillumination of the duodenum, and a duodenotomy with bimanual examination of the duodenal wall were also performed. The patient was found to have a 4 mm duodenal mass near the pylorus, which was excised. DISCUSSION: Pathology showed that the duodenal mass was primary gastrinoma. Serum gastrin levels taken four months postoperatively were normal and the repeat octreotide scan did not show any evidence of recurrence. CONCLUSION: Primary lymph node gastrinoma is a diagnosis of exclusion. The duodenum and pancreas must be fully explored to rule out a primary gastrinoma that may be occult.