A Rare Collision Tumor: Adenocarcinoma in the Ampulla of Vater and Neuroendocrine Tumor in the Lower Part of the Common Bile Duct

Cureus. 2021 Jun 24;13(6):e15882. doi: 10.7759/cureus.15882.


In the biliary tree, only three cases of neuroendocrine tumor (NET) synchronous with adenocarcinoma have been reported so far. We experienced a case of NET, grade 2 (G2), of the common bile duct associated with adenocarcinoma of the ampulla of Vater (AoV). A Japanese man at his 60's visited a local doctor, and obstructive jaundice was pointed out. Under the clinical diagnosis of carcinoma of the AoV, 20 x 20 mm, T3aN0M0 stage IIB, pylorus-preserving pancreaticoduodenectomy was performed. Dynamic computed tomography in an artery-dominant phase and microscopic examination revealed that the mass consisted of two different components; hypovascular, 2.5 cm-sized, exophytic adenocarcinoma in the AoV and hypervascular, 1.5 cm-sized, polypoid NET (G2) in the lower part of the common bile duct. The NET diffusely expressed neuroendocrine markers, including somatostatin receptor-2 (SSTR2), and adenocarcinoma cells arising from tubular adenoma focally expressed the neuroendocrine markers. Both malignancies were positive for caudal-type homeobox-2 (CDX2). It is presumed that NET occurred from intestinal-type adenoma/adenocarcinoma.

Keywords: adenocarcinoma; ampulla of vater; collision tumor; common bile duct; well differentiated neuroendocrine tumor.

Publication types

  • Case Reports