Abstract
RATIONALE: Pancreatic pseudocysts are fluid-filled sacs that typically develop as a complication of pancreatitis or abdominal trauma. These lesions are relatively rare, with an estimated incidence of 0.5 to 1 case per 100,000 people annually. While asymptomatic pseudocysts often resolve with conservative management, symptomatic cases or those complicated by infection, hemorrhage, or obstruction generally require surgical intervention. PATIENT CONCERNS: A 45-year-old man had recurrent black stools and vomiting blood. Initially diagnosed with gastritis, his condition worsened despite treatment, leading to severe bleeding. DIAGNOSES: Imaging showed a suspected stomach hematoma, but the cause was a pancreatic pseudocyst eroding the stomach wall and a gastric artery. INTERVENTIONS: Emergency surgery. OUTCOMES: The operation was successful, and the patient made a full recovery. Follow-up imaging at 2 months confirmed complete resolution of the gastric mass. LESSONS: This rare case highlights that pancreatic pseudocysts can cause major GI bleeding. Unexplained bleeding patients should be evaluated for pancreatic disease, especially with a history of pseudocysts.