Case Presentation:

A 47‐year‐old male with a history of chronic diarrhea for 10 years presented with diarrhea and hypokalemia. Potassium was 2.4 mEq/L. Further workup was negative for malabsorption or infectious causes of diarrhea. Stool osmolar gap was consistent with secretory diarrhea. Additional labs such as VIP, CA 19‐9, TSH, Cortisol, and 5‐HIAA were normal. Serum gastrin was markedly elevated (1648 pg/mL). A subsequent computerized tomographic scan of the abdomen showed a solid pancreatic mass in the junction of the head and uncinate process of pancreas. Alsc noted was an abnormal soft tissue growth in the lumen of the stomach, which was suspicious for a mass. An EUS–FNA was performed and the results were consistent with a neuroendocrine tumor. A gastric biopsy was consistent with Zollinger‐Ellison syndrome. His workup for multiple endocrine neoplasm (MEN 1) syndrome was negative. An octreotide scan did not show any evidence of metastatic disease. He was started on high‐dose proton pump inhibitors and octreotide following which his symptoms improved. Subsequently, patient underwent surgery and is now symptom free.


In 1955, Zollinger and Ellison described a syndrome characterized by ulceration of the upper jejunum, hypersecretion of gastric acid, and non‐beta islet cell tumors of the pancreas known as a gastrinoma. It is suspected in patients with extensive peptic ulcer disease or atypical ulcer locations. In 10% of patients, diarrhea is The only clinical manifestation and may precede ulcer disease by several years. Gastrinoma is diagnosed by high serum gastrin levels and a secretin stimulation test. Often it is not possible to pinpoint the localization of the primary tumor preoperatively. However, localization of the tumor is critical for curative surgical resection and treatment. Endoscopic ultrasound (EUS)–guided fine‐needle aspiration (FNA) has emerged as an accurate tool to identify pancreatic endocrine tumors (PETs). This case presentation displays the utilization of EUS–FNA in the diagnosis of PETs.


Considerable advances have been made in the medical and surgical management of Zollinger‐Ellison syndrome since its elucidation. EUS is a sophisticated imaging technique, able to accurately diagnose and localize PETs, which may not be detectable with other imaging modalities, EUS is the only modalily that can localize tumors and simultaneously obtain tissue for definitive diagnosis. This case illustrates the importance of considering newer diagnostic modalities such as EUS–FNA in the diagnosis of gastrinoma.

Author Disclosure:

A. Tiwari, none; A. Khanna, none; R. Daniel, none; N. Gunaratnam, none.