Neuroendocrine Tumor of the Ampulla of Vater: A Case Report

Mohammad S. Aman • Bidhan C. Das • Aminul Islam • Murshidul Arefin • Satya N. Gupta

Published: May 05, 2023

A neuroendocrine tumor of the ampulla of Vater is one of the rarest tumours in
hepatobiliary and pancreatic surgery. This case report, published in Cureus in May
2023, was co-authored by Dr. Murshidul Arefin with the team at the Department of
Hepatobiliary, Pancreatic and Liver Transplant Surgery, Bangabandhu Sheikh Mujib
Medical University (now Bangladesh Medical University), Dhaka.

What is a neuroendocrine tumor of the ampulla of Vater?

Neuroendocrine neoplasms arise from cells of the diffuse neuroendocrine system and
are most often found in the gastrointestinal tract, lungs, thymus and pancreas. The
2019 WHO classification splits them into well-differentiated neuroendocrine tumours
(NETs) and poorly differentiated neuroendocrine carcinomas, with NETs graded G1 to
G3 by mitotic rate and Ki-67 index. Although gastro-entero-pancreatic NETs make up
two-thirds of all NETs, only about 9% arise in the duodenum, and the ampulla of Vater
is rarer still. That rarity is exactly why these tumours are almost never predicted
before surgery.

How this case was diagnosed and treated

A 56-year-old woman presented with recurrent upper abdominal pain. Abdominal
ultrasonography showed multiple gallstones with a dilated common bile duct. Magnetic
resonance cholangiopancreatography was performed to evaluate the dilated duct and
revealed the double-duct sign. Upper gastrointestinal endoscopy then showed a bulged-out
ampulla of Vater. Biopsy and histopathology of the growth initially reported
adenocarcinoma, and the patient underwent a Whipple procedure
(pancreaticoduodenectomy).

What the specimen actually showed

Macroscopically the resected specimen contained a 2 cm growth involving the ampulla
of Vater. Microscopy was consistent with a well-differentiated neuroendocrine tumour,
grade 1 (low grade) — not the adenocarcinoma suggested on preoperative biopsy. The
diagnosis was confirmed on immunohistochemistry: pan-cytokeratin positive,
synaptophysin positive and focally chromogranin positive. The postoperative course was
uneventful apart from delayed gastric emptying.

Why this case report matters

The take-home message is that a detailed evaluation and a high index of suspicion are
required to diagnose this tumour, because preoperative biopsy can point to a different
diagnosis entirely. Once the diagnosis is correct, treatment is comparatively
straightforward. For surgeons in Bangladesh and other resource-limited settings, the
case underlines how much the final histopathology and immunohistochemistry of the
resected specimen can change the picture.

Read the full peer-reviewed paper in the embedded PDF below, or view it on Cureus
(DOI: 10.7759/cureus.38588).