Ampullary Adenocarcinoma with Incidental Pancreatic Neuroendocrine Tumor: Report of an Extremely Rare Case and Review of Literature.

Periampullary neoplasms are a heterogeneous group of tumors arising within 2 cm of the ampulla of Vater. Neuroendocrine tumors can originate throughout the entire body, from neuroendocrine cells. These neoplasms exhibit deep differences, according to their origin and biological behavior. We describe a case of a 79-year-old man who underwent pancreaticoduodenectomy for adenocarcinoma of the ampulla of Vater after proper staging. At gross histology, an incidental pancreatic neuroendocrine tumor was also documented. Despite two synchronous neoplasms, the patient survived 34 months with no evidence of recurrence at follow-up. The synchronous presence of a second primitive tumor in patients affected by a neuroendocrine tumor is reported in the literature; incidence is variable and the most common site is the gastrointestinal tract. Diagnostic workup for ampullary neoplasms includes abdominal computed tomography (CT) scan, magnetic resonance imaging (MRI) and endoscopic ultrasound (EUS). These investigations infrequently may detect subcentimetric lesions. We believe this case is currently extremely rare. Preoperative diagnosis of synchronous PanNET would not have changed our approach since surgical therapy represents the gold standard in resectable ampullary neoplasms, and it has a primary role in the prognosis of the present patient.