Background
Ampulla of Vater is an extremely rare site for neuroendocrine tumors (NET), accounting for less than 0.3% of gastrointestinal (GI) and 2% of ampullary malignancies. This case report highlights the circuitous diagnosis of this rare tumor in a patient with a history of primary biliary cholangitis presenting with epigastric pain and severe pruritis.
Case Presentation
A 58-year-old female with history of sarcoidosis and primary biliary cholangitis status post sphincterotomy eight months prior, presented with worsening epigastric pain, fatigue, and weight loss over 6 months. Physical exam showed right upper quadrant tenderness. Labs revealed elevated alanine and aspartate aminotransferases at 415 and 195 units/L, with bilirubin of 0.3 mg/dl. Computerized tomography (CT) revealed a 2.3x3.2x4.0 cm peripancreatic hypodensity associated with phlegmon, pancreatic ductal dilation and pneumobilia. Magnetic resonance imaging (MRI) demonstrated a pancreatic head mass. Positron emission tomogram (PET) was negative for distant metastases. After discussion of management options, patient opted for Whipple procedure. The surgical pathology was consistent with invasive ampullary ductal carcinoma of the small intestine, pancreaticobiliary type. However, staining for synaptophysin and chromogranin were positive, with Ki-67 < 55%. Tumor board review confirmed neuroendocrine tumor of the ampulla of Vater. NCCN guidelines recommended active surveillance due to locoregional disease without positive margins or lymph nodes, advising routine follow-up and imaging.
Discussion
Neuroendocrine tumors (NET) at the Ampulla of Vater are exceedingly rare. Often manifesting as obstructive jaundice, they pose diagnostic hurdles, especially in patients with anatomical variations like scarring from primary biliary cholangitis. In a case series of 20 ampullary tumors, only one was neuroendocrine, highlighting their rarity. Accurate diagnosis, achieved through surgical biopsy and immunohistochemical testing, is crucial for appropriate management. Following NCCN guidelines for gastrointestinal NETs, our patient avoided unnecessary systemic treatment meant for adenocarcinoma, preserving her quality of life. Reporting such cases is essential for advancing understanding and refining patient care.
Conclusions
This case had evolving diagnoses, altering both the prognosis and treatment standards. Comorbid primary biliary cholangitis and high-grade tumor complexity posed diagnostic challenges, which was finally confirmed by surgical biopsy. Reporting such cases is vital in aiding tumor management and patient outcomes.