A Perplexing Case of Abdominal Pain That Led to the Diagnosis of Zollinger-Ellison Syndrome

Abstract

Zollinger-Ellison Syndrome (ZES) is a rare clinical disorder, characterized by hypersecretion of gastric acid and multiple ulcers distal to the duodenal bulb. This occurs via the release of gastrin by neuroendocrine tumors known as gastrinomas. Patients with ZES present with nonspecific GI symptoms, which often leads to a delay in diagnosis. We present a case that highlights the importance of increased awareness of ZES in patients with chronic GI complaints. The patient is a 55 year-old female with a history of chronic pancreatitis, who had been following in the GI clinic for several years, secondary to abdominal pain, nausea, and diarrhea. However, despite extensive testing, an etiology of her symptoms had not been determined. She initially underwent esophagogastroduodenoscopy (EGD) and endoscopic ultrasound (EUS), which only showed gastropathy and chronic pancreatitis. Magnetic resonance cholangiopancreatography was unremarkable. She underwent cholecystectomy, but continued to have symptoms, which prompted a repeat EGD. This showed a deep ulceration at the gastro-esophageal junction (LA Grade D), a 2 cm deeply cratered ulcer in the second portion of the duodenum, and a stricture in the third portion of the duodenum (Figure 1). Biopsies showed gastritis and duodenitis without evidence of malignancy. These findings were suspicious for ZES, and work up was initiated. Serum gastrin level was elevated at 1639 pg/mL, but repeat EUS and CT abdomen/pelvis did not reveal any pancreatic or duodenal masses. Somatostain receptor scintigraphy (SRS) was obtained, which showed two small lesions in the gastrinoma triangle (Figure 2). She subsequently underwent a Whipple pancreaticoduodenectomy. Pathology was positive for four microscopic foci (largest 0.1 cm) of a well-differentiated neuroendocrine tumor with evidence of metastasis to two peri-pancreatic nodes. She reported improvement in her symptoms after surgery. This case highlights the need for increased awareness of ZES in patients with unexplained GI complaints. The time to diagnosis in this patient was over seven years, which may have been reduced if ZES was considered earlier. This case also emphasizes the use of multiple modalities in the diagnosis of ZES. SRS, which ultimately detected the gastrinoma in this patient, has a higher sensitivity than CT/MRI. EUS also has a high sensitivity; however, a pancreatic mass was not identified with EUS in our patient, possibly secondary to the small size of the tumor.Figure 1Figure 2