Somatostatinoma of the Ampulla of Vater: A Systematic Review

Background and Aims: Somatostatinoma of the ampulla of Vater (SAV) is a rare neuroendocrine tumor that usually appears with atypical clinical manifestations and is associated with Von Recklinghausen’s disease. The aims of this study were to systematically review the literature regarding SAV and to highlight the clinicopathological characteristics and optimal therapeutic management of this rare entity. 
Methods: A systematic search of the literature in PubMed/Medline and Scopus databases was performed by two independent investigators, including all case reports and case series concerning SAVs from 1980 until September 2021. 
Results: In total, 37 articles were retrieved, including 43 patients, with a male to female ratio of 1.8:1 and a mean age of 46.8 ± 11.3 years (mean, SD). For 23 out of 43 patients (53.5%), Von Recklinghausen’s disease was proved. The main clinical manifestations were abdominal pain (41.9%), jaundice (27.9%), weight loss (20.9%) and bowel disorders (20.9%). Typical histological findings included psammoma bodies, nests or clusters of epithelial cells with eosinophilic cytoplasm, while somatostatin staining was positive in 35 patients (81.4%), chromogranin-A in 21 patients (48.8%) and synaptophysin in 18 patients (41.9%). Surgery was the initial therapeutic approach in 34 patients (79.1%), whereas Whipple’s procedure was the preferred surgical approach in 23 patients (53.4%). The longest survival among included patients was 13 years and only two postoperative deaths (4.7%) were reported. 
Conclusions: Somatostatinomas of the ampulla of Vater are rare malignancies that require increased physicians’ suspicion and accurate surgical approach in order to achieve optimal therapeutic results.