Ampullary carcinoma detected incidentally during ERCP: a case report and literature review

Early ampullary tumors are challenging to diagnose due to their complex surrounding structures and deep anatomical location. We report a rare case in which enhanced computed tomography (CT), magnetic resonance imaging (MRI), magnetic resonance cholangiopancreatography (MRCP) and endoscopic ultrasound (EUS) all failed to detect the lesion, with the diagnosis ultimately established through endoscopic retrograde cholangiopancreatography (ERCP). The patient subsequently underwent timely surgical resection. This case highlights the irreplaceable value of ERCP in detecting early and occult ampullary tumors.