RESUMEN
RATIONALE: Pancreatic insulinomas are the most frequent pancreatic endocrine neoplasms. They are insulin-secreting pancreatic tumors that induce extreme, recurrent, and near-fatal hypoglycemia. Insulinomas affect 1 to 4 individuals in a million of the general population and account for about 1% to 2% of all pancreatic tumors. PATIENT CONCERNS: Recurrent episodes of sweating, tremor, weakness, confusion, palpitation, blurred vision, and fainting for 2 months and was misdiagnosed as having atrial fibrillation. DIAGNOSIS: He was misdiagnosed as having atrial fibrillation to highlight the importance of atrial fibrillation as unusual mimicker of insulinoma and to encourage clinicians about the importance of early and appropriate management in such cases. INTERVENTIONS: Endoscopic ultrasound for the pancreatic parenchyma was done, and it showed a hypoechoic homogenous mass located at the pancreatic head measuring 12 mm × 15 mm with no local vascular involvement, blue in elastography, hypervascular with Doppler study, and a normal pancreatic duct diameter. OUTCOMES: His condition was stable, and he was discharged home 2 days later. CONCLUSION: The diagnosis of insulinoma is usually difficult and late due to the extremely low incidence of the disease and the similarity of its clinical presentation to numerous other conditions, the most reported is epilepsy.