Stone-induced spontaneous pancreatico-gastric fistula in chronic calcific pancreatitis presenting with upper gastrointestinal bleeding: a rare case report

Pancreatico-gastric fistula is a rare sequela of chronic calcific pancreatitis and only infrequently presents with upper gastrointestinal bleeding, often posing a diagnostic challenge. We describe a 63-year-old male with alcohol-related chronic calcific pancreatitis who presented with hematemesis and melena. Cross-sectional imaging demonstrated a subepithelial gastric lesion closely resembling a gastrointestinal stromal tumor, along with obliteration of the fat planes between the stomach and pancreas. A large calcified calculus was identified within the main pancreatic duct, lying in close proximity to the posterior gastric wall. Endoscopic ultrasound findings further favored a neoplastic etiology. However, surgical exploration revealed a spontaneous pancreatico-gastric fistula resulting from direct erosion of the impacted ductal stone into the stomach. The patient underwent wide local excision of the involved gastric segment along with a Frey’s procedure. Postoperatively, he had a biochemical leak, formerly classified as grade A postoperative pancreatic fistula, and had an uneventful recovery. This case illustrates an unusual pathogenic mechanism of fistula formation, where pressure-induced erosion by a pancreatic duct calculus mimicked a gastric neoplasm and presented with upper gastrointestinal bleeding.