Case Presentation: A 78-year-old woman with hypertension and a prior intracranial aneurysm treated with coiling, presented after a syncopal episode at home. She experienced epigastric pain during a family meal, sat down, and briefly lost consciousness without trauma. She reported similar episodes earlier in the year, for which cardiac evaluation was unremarkable.On admission, vital signs were stable. Laboratory evaluation revealed potassium 2.9 mmol/L, anion gap 18, bicarbonate 20 mmol/L, alkaline phosphatase 165 U/L, aspartate aminotransferase 474 U/L, alanine aminotransferase 463 U/L, total bilirubin 0.6 mg/dL, and lipase greater than 3000 U/L. Lipid panel and complete blood count were normal. She denied alcohol or drug use and had no prior history of pancreatitis. Surgical history included cholecystectomy.Computed tomography of the abdomen showed no pancreatic inflammation. Liver ultrasound revealed mild hepatomegaly, moderate steatosis, and a dilated common bile duct measuring 13 mm. Magnetic resonance cholangiopancreatography (MRCP) was delayed due to her aneurysm history and the patient underwent endoscopic retrograde cholangiopancreatography (ERCP) . ERCP revealed an ulcerated ampullary mass obstructing both the bile and pancreatic ducts. A biliary stent was placed, and biopsy confirmed a well-differentiated grade 2 neuroendocrine tumor. Endoscopic ultrasound and imaging demonstrated a 30 mm lesion in the pancreatic head with peripancreatic adenopathy. Patient was scheduled for pancreaticoduodenectomy.
Discussion: Acute pancreatitis resulting from ampullary obstruction due to a neuroendocrine tumor (NETs) is an uncommon presentation, particularly in patients without a history of pancreatic disease. NETs represent a rare subset of gastrointestinal neoplasms, accounting for less than 2% of all neuroendocrine tumors and a very small fraction of ampullary malignancies. Their clinical presentation is often nonspecific, ranging from abdominal pain and jaundice to incidental detection during evaluation for unrelated conditions. In our patient, the tumor manifested with acute pancreatitis, a particularly uncommon presentation that likely resulted from simultaneous obstruction of both the biliary and pancreatic ducts. While gallstones and alcohol remain the most common etiologies of pancreatitis, clinicians must remain vigilant for atypical causes.The diagnostic process in this case underscores the challenges associated with identifying ampullary NETs. Imaging studies such as computed tomography or ultrasound may reveal ductal dilation but are frequently insufficient to detect small periampullary lesions. MRCP is a noninvasive option, though its use may be limited in patients with contraindications, as seen in our case. ERCP not only facilitated the diagnosis but also provided therapeutic biliary decompression. Endoscopic ultrasound (EUS) is also highly sensitive for lesion detection and should be integrated into the diagnostic algorithm.Management of ampullary NETs is influenced by tumor size, grade, and the presence of nodal disease. Surgical resection, most commonly pancreaticoduodenectomy, remains the treatment of choice and offers the best long-term outcomes.
Conclusions: This case highlights the need to consider rare malignant etiologies in acute pancreatitis, the diagnostic value of ERCP when conventional imaging is inconclusive, and the importance of maintaining a broad differential in elderly patients presenting with atypical symptoms.