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.

Duodenal somatostatinoma presenting as obstructive jaundice with the coexistence of a gastrointestinal stromal tumour in neurofibromatosis type 1: a case with review of the literature.

Somatostatinomas are rare neuroendocrine tumours, mostly located in the pancreas or duodenum, with an estimated incidence of 1 in 40 million. Duodenal somatostatinomas (DSs) are usually found in association with neurofibromatosis type 1 (NF1), tuberous sclerosis and Von Hippel-Lindau syndrome. Gastrointestinal stromal tumours (GIST) have also been described in NF1, but the association with somatostatinoma is very uncommon. We report the case of a patient with NF1 who presented with obstructive jaundice due to multiple firm nodules around the ampulla of Vater. A pancreaticoduodenectomy was performed and revealed a 1 cm duodenal/ampullary mass which stained positive for somatostatin, together with a GIST also found on the duodenal wall. Despite its rarity, ampullary somatostatinomas should be considered in the differential diagnosis of biliary tract dilation in patients with NF1.

Prognostic relevance of proliferation-related miRNAs in pancreatic neuroendocrine neoplasms

Objective: Pancreatic neuroendocrine neoplasms (PanNENs) are rare tumors arising from the endocrine pancreas; however, their prognosis differs significantly upon their proliferative state, which is characterized by histopathological grading. MiRNAs are small, noncoding RNAs posttranscriptionally regulating gene expression. Our aim was to identify miRNAs with altered expression upon proliferation which can be used as prognostic biomarkers in PanNENs. Methods: MiRNA expression profiles of 40 PanNENs were downloaded from Gene Expression Omnibus and were reanalyzed upon tumor grades (discovery cohort). Results of the reanalysis were confirmed by qRT-PCR analysis of five miRNAs on an independent validation cohort of 63 primary PanNEN samples. Cox proportional hazards survival regression models were fit for both univariate and multivariate analysis to determine the miRNAs' effect on progression-free and overall survival. Results: Nineteen miRNAs displayed differential expression between tumor grades. The altered expression of three out of five chosen miRNAs was successfully validated; hsa-miR-21, hsa-miR-10a and hsa-miR-106b were upregulated in more proliferative PanNENs compared to Grade 1 tumors. In univariate analysis, higher expression of tissue hsa-miR-21, hsa-miR-10a and hsa-miR-106b of primary PanNENs predicted worse progression-free and overall survival; however, multivariate analysis only confirmed the expression of hsa-miR-21 as an independent prognostic factor. Conclusions: The expression of hsa-miR-106b, hsa-miR-10a and especially hsa-miR-21 has prognostic relevance regarding progression-free and overall survival in patients with PanNENs.

Novel insights into the polycythemia-paraganglioma-somatostatinoma syndrome.

Worldwide, the syndromes of paraganglioma (PGL), somatostatinoma (SOM) and early childhood polycythemia are described in only a few patients with somatic mutations in the hypoxia-inducible factor 2 alpha (HIF2A). This study provides detailed information about the clinical aspects and course of 7 patients with this syndrome and brings into perspective these experiences with the pertinent literature. Six females and one male presented at a median age of 28 years (range 11-46). Two were found to have HIF2A somatic mosaicism. No relatives were affected. All patients were diagnosed with polycythemia before age 8 and before PGL/SOM developed. PGLs were found at a median age of 17 years (range 8-38) and SOMs at 29 years (range 22-38). PGLs were multiple, recurrent and metastatic in 100, 100 and 29% of all cases, and SOMs in 40, 40 and 60%, respectively. All PGLs were primarily norepinephrine-producing. All patients had abnormal ophthalmologic findings and those with SOMs had gallbladder disease. Computed tomography (CT) and magnetic resonance imaging revealed cystic lesions at multiple sites and hemangiomas in 4 patients (57%), previously thought to be pathognomonic for von Hippel-Lindau disease. The most accurate radiopharmaceutical to detect PGL appeared to be [18F]-fluorodihydroxyphenylalanine ([18F]-FDOPA). Therefore, [18F]-FDOPA PET/CT, not [68Ga]-(DOTA)-[Tyr3]-octreotate ([68Ga]-DOTATATE) PET/CT is recommended for tumor localization and aftercare in this syndrome. The long-term prognosis of the syndrome is unknown. However, to date no deaths occurred after 6 years follow-up. Physicians should be aware of this unique syndrome and its diagnostic and therapeutic challenges.

Combined presence of multiple gastrointestinal stromal tumors along with duodenal submucosal somatostatinoma in a patient with neurofibromatosis type 1.

Neurofibromatosis type-1 (NF-1) is an autosomal dominant disorder, with increased risk of developing benign and malignant tumors of the gastrointestinal tract (GIT). However, the synchronous presence of multiple GIT stromal tumors and duodenal submucosal somatostatinoma, like in this 50-year-old female NF-1 patient, is very rare. She presented with hematemesis, malena, along with multiple neurofibromas all over the body. Thorough radiological and peroperative work-up revealed multiple ulcerated submucosal and serosal nodules in the proximal small intestine. Histological work-up revealed diagnosis of a duodenal submucosal somatostatinoma with multifocal serosal gastrointestinal stromal tumors. This case is being reported to highlight the rare coincidence of multiple GIT tumors in an NF-1 patient.

The Coexistence of Somatostatinoma and Gastrointestinal Stromal Tumor in the Duodenum of a Patient with Von Recklinghausen's Disease.

We herein describe a case of somatostatinoma coexisting with a gastrointestinal stromal tumor (GIST) in the duodenum of an 81-year-old woman with Von Recklinghausen's disease (VRD) and common bile duct stone who presented with diarrhea of three months in duration. Gastroduodenoscopy revealed an ulcer on the second part of the duodenum. A 2.1-cm enhancing tumor was observed to extend from the ulcer on an abdominal computed tomography scan. Subtotal stomach-preserving pancreaticoduodenectomy revealed a somatostatinoma on the papilla of the vater and duodenal GIST. There have been only eight reports on VRD associated with ampullary somatostatinoma and GIST. An awareness of this possibility in patients with gastrointestinal lesions is necessary for proper treatment and patient management.

Pancreatic somatostatinoma diagnosed preoperatively: report of a case.

CONTEXT: Somatostatinoma is a rare neoplasm of the pancreas. Preoperative diagnosis is often difficult. CASE REPORT: We report a 72-year-old woman with a pancreatic head tumor measuring 37 mm in diameter, and enlargement of the lymph nodes on the anterior surface of the pancreatic head and the posterior surface of the horizontal part of the duodenum. Laboratory data showed an elevated plasma somatostatin concentration. Examination of a biopsy specimen of the pancreatic head mass obtained by endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) showed histopathological features of a neuroendocrine tumor. Immunohistochemical staining showed that the tumor cells were positive for somatostatin, leading to a preoperative diagnosis of pancreatic somatostatinoma. The patient underwent pylorus-preserving pancreaticoduodenectomy. The plasma somatostatin concentration decreased progressively after surgery. CONCLUSIONS: A rare case of pancreatic somatostatinoma with lymph node metastases was presented. Immunohistochemical analysis of a biopsy specimen obtained by EUS-FNA was useful for preoperative diagnosis.

Case report: recurrent acute pancreatitis secondary to papillary somatostatinoma--a new association.

Acute pancreatitis may rarely be caused by papillary mass lesions such as adenocarcinomas and neuroendocrine tumours. Occasionally these papillary lesions may cause recurrent episodes of acute pancreatitis and patients presenting in this way require further pancreatic investigation. We believe this to be the first reported case of a duodenal papillary somatostatinoma causing recurrent acute pancreatitis. The patient was investigated with multiple imaging modalities, both at endoscopy and with more traditional radiology, and treated with resection by Whipple's pancreaticoduodenectomy. If diagnosed early in the absence of distant metastases the prognosis of papillary somatostatinoma with tumour resection is excellent.

New syndrome of paraganglioma and somatostatinoma associated with polycythemia.

PURPOSE: The occurrence of ≥ two distinct types of tumors, one of them paraganglioma (PGL), is unusual in an individual patient, except in hereditary cancer syndromes. PATIENTS AND METHODS: Four unrelated patients were investigated, with thorough clinical evaluation. Plasma and tissue catecholamines and metanephrines were measured by high-performance liquid chromatography. Anatomic and functional imaging were performed for tumor visualization. Germline and tumor tissue DNA were analyzed for hypoxia-inducible factor 2 alpha (HIF2A) mutations. The prolyl hydroxylation and stability of the mutant HIF2α protein, transcriptional activity of mutant HIF2A, and expression of hypoxia-related genes were also investigated. Immunohistochemical staining for HIF1/2α was performed on formalin-fixed, paraffin-embedded tumor tissue. RESULTS: Patients were found to have polycythemia, multiple PGLs, and duodenal somatostatinomas by imaging or biochemistry with somatic gain-of-function HIF2A mutations. Each patient carried an identical unique mutation in both types of tumors but not in germline DNA. The HIF2A mutations in these patients were clustered adjacent to an oxygen-sensing proline residue, affecting HIF2α interaction with the prolyl hydroxylase domain 2-containing protein, decreasing the hydroxylation of HIF2α, and reducing HIF2α affinity for the von Hippel-Lindau protein and its degradation. An increase in the half-life of HIF2α was associated with upregulation of the hypoxia-related genes EPO, VEGFA, GLUT1, and END1 in tumors. CONCLUSION: Our findings indicate the existence of a new syndrome with multiple PGLs and somatostatinomas associated with polycythemia. This new syndrome results from somatic gain-of-function HIF2A mutations, which cause an upregulation of hypoxia-related genes, including EPO and genes important in cancer biology.

Gastrointestinal hormones stimulate growth of Foregut Neuroendocrine Tumors by transactivating the EGF receptor.

Foregut neuroendocrine tumors [NETs] usually pursuit a benign course, but some show aggressive behavior. The treatment of patients with advanced NETs is marginally effective and new approaches are needed. In other tumors, transactivation of the EGF receptor (EGFR) by growth factors, gastrointestinal (GI) hormones and lipids can stimulate growth, which has led to new treatments. Recent studies show a direct correlation between NET malignancy and EGFR expression, EGFR inhibition decreases basal NET growth and an autocrine growth effect exerted by GI hormones, for some NETs. To determine if GI hormones can stimulate NET growth by inducing transactivation of EGFR, we examined the ability of EGF, TGFα and various GI hormones to stimulate growth of the human foregut carcinoid,BON, the somatostatinoma QGP-1 and the rat islet tumor,Rin-14B-cell lines. The EGFR tyrosine-kinase inhibitor, AG1478 strongly inhibited EGF and the GI hormones stimulated cell growth, both in BON and QGP-1 cells. In all the three neuroendocrine cell lines studied, we found EGF, TGFα and the other growth-stimulating GI hormones increased Tyr(1068) EGFR phosphorylation. In BON cells, both the GI hormones neurotensin and a bombesin analogue caused a time- and dose-dependent increase in EGFR phosphorylation, which was strongly inhibited by AG1478. Moreover, we found this stimulated phosphorylation was dependent on Src kinases, PKCs, matrix metalloproteinase activation and the generation of reactive oxygen species. These results raise the possibility that disruption of this signaling cascade by either EGFR inhibition alone or combined with receptor antagonists may be a novel therapeutic approach for treatment of foregut NETs/PETs.

Somatostatin-producing duodenal carcinoma: clinicopathological description of a case.

Somatostatinomas are rare functioning neoplasms usually arising in the pancreas and duodenum. They are seldom associated with typical clinical symptoms. Their diagnosis is confirmed only by histological and immunohistochemical studies and the presence of specific hormones. Two distinct clinicopathological forms of somatostatinoma exist: duodenal and pancreatic somatostatinomas. Clinically, compared to pancreatic somatostatinomas, duodenal somatostatinomas are more often associated with nonspecific symptoms and neurofibromatosis, but less often with somatostatinoma syndrome or metastasis. We report a case of somatostatin-producing duodenal carcinoma in a 45-year-old female with neither neurofibromatosis nor somatostatinoma syndrome. Abdominal computed tomography showed a 18 mm mass in the duodenum which had given rise to multiple lymph node metastases. Although the endoscopic biopsies were free of malignancy, the patient subsequently underwent Whipple's operation for the duodenal mass. Immunohistochemical analysis confirmed the diagnosis of somatostatin-producing carcinoma.

Severely fluctuating blood glucose levels associated with a somatostatin-producing ovarian neuroendocrine tumor.

CONTEXT: Somatostatin-producing tumors are a rare type of neuroendocrine tumor. Their effects on blood glucose levels have been variously reported, and detailed reports have been scarce. OBJECTIVE: The aim of this study was to identify the reasons for the extraordinary blood glucose fluctuations in a case with no previous history of diabetes. PATIENTS AND METHODS: A 68-yr-old nondiabetic woman with an ovarian tumor was suffering from hyper- and hypoglycemia. Based on the results of an oral glucose tolerance test and continuous glucose monitoring, we speculated that the fluctuating blood glucose level was accompanied not only by a low insulin level but also by low counter-regulatory hormones levels, and that those broad hormonal suppressions were caused by a high somatostatin level produced in the ovarian tumor. We performed an oophorectomy and assessed the pathology of the tumor and changes in the blood glucose profile as well as hormonal levels postoperatively. RESULTS: The blood glucose level was completely normalized after the oophorectomy. Insulin secretion was also normalized. Histological examination showed that the tumor comprised a mature cystic teratoma and a stromal carcinoid. Immunohistochemically, the stromal carcinoid component was positive for somatostatin. The somatostatin level was 8505 pmol/liter preoperatively, which dropped down to 71.5 pmol/liter postoperatively. We found two previous reports of somatostatin-producing ovarian neuroendocrine tumors. Somatostatin levels among cases of ovarian origin were much higher than those among cases of gastrointestinal origins, and cases of ovarian origin all experienced blood glucose fluctuations. CONCLUSION: Extremely high somatostatin levels and blood glucose fluctuations may be characteristics of somatostatin-producing ovarian neuroendocrine tumors.

Quantum dot immunocytochemical localization of somatostatin in somatostatinoma by Widefield Epifluorescence, super-resolution light, and immunoelectron microscopy.

Quantum dot nanocrystal probes (QDs) have been used for detection of somatostatin hormone in secretory granules of somatostatinoma tumor cells by immunofluorescence light microscopy, super-resolution light microscopy, and immunoelectron microscopy. Immunostaining for all modalities was done using sections taken from an epoxy resin-embedded tissue specimen and a similar labeling protocol. This approach allowed assessment of labeling at light microscopy level before examination at super-resolution and electron microscopy level and was a significant aid in interpretation. Etching of ultrathin sections with saturated sodium metaperiodate was a critical step presumably able to retrieve some tissue antigenicity masked by processing in epoxy resin. Immunofluorescence microscopy of QD-immunolabeled sections showed somatostatin hormone localization in cytoplasmic granules. Some variable staining of tumor gland-like structures appeared related to granule maturity and dispersal of granule contents within the tumor cell cytoplasm. Super-resolution light microscopy demonstrated localization of somatostatin within individual secretory granules to be heterogeneous, and this staining pattern was confirmed by immunoelectron microscopy.