Somatostatin-Immunoreactive Pancreaticoduodenal Neuroendocrine Neoplasms: Twenty-Three Cases Evaluated according to the WHO 2010 Classification

Abstract

Background/Objective: Neuroendocrine neoplasms of the pancreas and duodenum with predominant or exclusive immunoreactivity for somatostatin (pdSOMs) are rare, and knowledge about tumour biology, treatment, survival and prognostic factors is limited. This study aims to describe clinical, pathological and biochemical features as well as treatment and prognosis of pdSOMs. Design: Twenty-three patients with pdSOM (9 duodenal, 12 pancreatic and 2 unknown primary tumours) were identified from our prospective neuroendocrine tumour database, and data according to the study aims were recorded. Results: Among the 9 patients with duodenal SOM, the male/female ratio was 4/5. All males and 1 female had neurofibromatosis type 1. Seven patients had stage 1A/B and 2 had stage 2B disease. The Ki-67 index was 1-5% (median 2%). Plasma somatostatin was elevated in the patients with 2B disease. Of the 14 patients with pancreatic SOM or an unknown primary tumour, the male/female ratio was 2/12. One male had multiple endocrine neoplasia type 1. Five had stage 1A/2B and 9 had stage 4. The Ki-67 index was 1-40% (median 7%). Plasma somatostatin was elevated in 7 patients. Patients reported symptoms related to the somatostatinoma syndrome, but none fulfilled the criteria for a full syndrome. Primary tumour in the pancreas, metastatic disease at diagnosis and higher tumour grade were all associated with significantly poorer survival. Conclusion: None of the patients with pdSOM presented with the full somatostatinoma syndrome. Prognostic factors are localisation of the primary tumour, dissemination and tumour grade. A Ki-67 index of 5% may discriminate the course of the disease.

Four Neuroendocrine Tumor Types and Neuroendocrine Carcinoma of the Duodenum: Analysis of 203 Cases

“…Although none of our AST cases showed unequivocal signs of somatostatin-related endocrine hyperfunction relieved by tumor excision, these findings (particularly diabetic ketoacidosis) have been reported by others [26,27,28]. Another point of potential clinical interest is AST's frequent lack of type 2A somatostatin receptors, coupled with the intense expression of type 5 receptors, which may have implications for the choice of appropriate somatostatin analogue therapy [29,30].…”

Familial Duodenal Somatostatinomatosis Not Associated With a Known Genetic Syndrome

“…The absence of somatostatinoma syndrome is not surprising because most patients with somatostatinoma do not have it, especially when the tumor burden is small. [1][2][3][4] Interestingly, although the somatostatinomas in the father and daughter were very similar between themselves, they were quite different from sporadic duodenal somatostatinomas in the number and location of tumors and in tumor marker expression. All 21 sporadic duodenal somatostatinomas in 2 studies are unifocal; most are located in the ampulla or otherwise in the second portion of duodenum; only 2 are located in the duodenal bulb.…”

Frequency and Causes of False-Positive Elevated Plasma Concentrations of Fasting Gut Hormones in a Specialist Neuroendocrine Tumor Center

“…Somatostatinomas are classically associated with a clinical triad of diabetes mellitus, cholelithiasis and diarrhea, collectively termed “somatostatinoma syndrome.” However most patients only have partial manifestation of this triad ( 21 ). Somatostatinomas are very rare (incidence approximately 1 in 40 million persons per year) and approximately 45% are thought to arise in patients with MEN1 ( 3 ).…”