Adenocarcinoma Synchronous with Neuroendocrine Tumor in Ampulla of Vater: A Rare Presentation

Abstract

Neuroendocrine tumors (NET)of gastrointestinal tract are rare and the presence of synchronous lesions with adenocarcinoma is even more uncommon. In the duodenum, NETs constitute 5.7 to 7.9% of the neuroendocrine neoplasms of the gastroenteropancreatic tract. We present a case of 65-year-old male who presented with abdominal pain and weight loss who was found to have both adenocarcinoma arising from tubulovillous adenoma as well poorly differentiated NET from the ampulla of vater. A 65-year-old male with past medical history of Barrett's esophagus, presented with upper abdominal pain, fevers/chills and significant unintentional weight loss. Vitals on presentation were stable. Pertinent labs included albumin 3.4 g/dL, total bilirubin 1 mg/dL, ALP 575 U/L, ALT 106 U/L, AST 115 U/L, amylase 86 U/L, lipase 773 U/L, CRP 10.7 mg/L. He was also found to have elevated tumor markers with CA (19-9) 141.2 U/mL, CEA 5.2 ng/mL. MRI of abdomen revealed dilated common bile duct (CBD) with faint signal dropout measuring 2-3 mm at distal CBD. He underwent endoscopic retrograde cholangiopancreatography (ERCP) which revealed a friable, nodular, and ulcerated appearing ampulla and biopsies were taken were taken with cold forceps. The cholangiogram did not identify any biliary involvement of the mass. Biliary stent was subsequently placed with improvement of liver enzymes. Biopsy of the ampulla revealed poorly differentiated adenocarcinoma. Staging computer tomography (CT scan) of the chest, abdomen, and pelvis revealed no discrete pancreatic mass or any metastatic disease. The patient underwent a Whipple pancreaticoduodenectomy. Pathology from the ampulla revealed both moderately differentiated adenocarcinoma in addition to a synchronous poorly differentiated, grade III neuroendocrine carcinoma (15 mitosis/10 HPF with proliferation fraction of 30% Ki-67). The presence of neuroendocrine tumor in synchronous with adenocarcinoma is rare. To our knowledge, no case report reporting synchronous lesion of adenocarcinoma with neuroendocrine tumor of ampulla of vater has been reported in the literature. It is unclear if there is a common link in the pathogenesis of the synchronous lesions or are they merely coincidental. Further studies are needed to determine the pathogenesis of these lesions.