A case of refractory esophageal stricture due to occult gastrinoma of the duodenum

Gastrinoma may cause refractory esophageal stricture due to gastro-esophageal reflux disease (GERD), but imaging technologies have limited power in its diagnosis. A 74-year-old female with a history of peptic ulcers suffered from repeated epigastralgia, and she visited a local hospital. An esophago-gastro-duodenoscopy (EGD) demonstrated severe reflux esophagitis and multiple peptic ulcers. Blood examination revealed a high value of fasting serum gastrin. Multi-detector computed tomography showed a hypervascular and tiny nodule in duodenal bulb, although other imaging technologies did not. Short-term medication with a proton pump inhibitor or potassium-competitive acid blocker was intermittently provided, but dysphagia was repeatedly worsened, and she was referred to our division. Serum hypergastrinemia was retained, and EGD reexamination depicted esophageal stricture, treated by multiple sessions of endoscopic balloon dilatation. Primary tumor was not identified by the morphological imaging technologies, but a selective arterial secretagogue injection test suggested its existence in the duodenum or pancreatic head. Pancreaticoduodenectomy was performed, and histological study identified 2 mm-sized microgastrinoma buried in Brunner`s glands on the posterior wall of the duodenum bulb. We reported a case with difficulty in diagnosis of the smallest sporadic gastrinoma of the duodenum, which might cause refractory GERD-associated stricture.