Primary lymph node gastrinoma or occult duodenal microgastrinoma with lymph node metastases in a MEN1 patient: the need for a systematic search for the primary tumor

Current understanding of pathogenetic mechanisms in neuroendocrine neoplasms

INTRODUCTION

Despite the fact that important advances in research on neuroendocrine neoplasms (NENs) have been made, consistent data about their pathogenetic mechanism are still lacking. Furthermore, different primary sites may recognize different pathogenetic mechanisms.

AREAS COVERED

This review analyzes the possible biological and molecular mechanisms that may lead to NEN onset and progression in different organs. Through extensive research of the literature, risk factors including hypercholesterolemia, inflammatory bowel disease, chronic atrophic gastritis are evaluated as potential pathogenetic mechanisms. Consistent evidence is available regarding sporadic gastric NENs and MEN1 related duodenopancreatic NENs precursor lesions, and genetic-epigenetic mutations may play a pivotal role in tumor development and bone metastases onset. In lung neuroendocrine tumors (NETs), diffuse proliferation of neuroendocrine cells on the bronchial wall (DIPNECH) has been proposed as a premalignant lesion, while in lung neuroendocrine carcinoma nicotine and smoke could be responsible for carcinogenic processes. Also, rare primary NENs such as thymic (T-NENs) and Merkel cell carcinoma (MCC) have been analyzed, finding different possible pathogenetic mechanisms.

EXPERT OPINION

New technologies in genomics and epigenomics are bringing new light to the pathogenetic landscape of NENs, but further studies are needed to improve both prevention and treatment in these heterogeneous neoplasms.

Multiple endocrine neoplasia type 1 with Zollinger-Ellison syndrome: clinicopathological analysis of a Japanese family with focus on menin immunohistochemistry

Background

Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant disorder characterized by the occurrence of multiple epithelial neuroendocrine tumors (NETs) and non-NETs in various organs. MEN1 encodes a 610-amino acid-long tumor suppressor protein, menin. The optimal treatment for multiple tumors, identification of the most critical tumors for patient prognosis, and menin immunohistochemistry findings remain controversial. Therefore, we aimed to elucidate these issues through a histological analysis of tumors and tumor-like lesions in a Japanese family, comprising a father and his two sons, who had MEN1 with Zollinger-Ellison syndrome (ZES).

Patients and methods

All family members had a germline alteration in exon 10, c.1714-1715 del TC of MEN1, and exhibited multiple synchronous and metachronous tumors. The patients had pulmonary NETs, hyperparathyroidism, hypergastrinemia, pituitary adenomas, pancreaticoduodenal NETs, adrenocortical adenoma with myelolipoma, nodular goiter of the thyroid, lipomas, and angiofibroma. Most tumors were resected and histologically examined. We compared their clinical courses and tumor histology, and conducted menin immunohistochemistry (IHC).

Results

Two patients died of pulmonary NET G2. One patient who underwent pancreaticoduodenectomy was cured of ZES; however, the two other patients who did not undergo pancreaticoduodenectomy suffered persistent ZES despite treatment with octreotide. Menin IHC revealed varying NET intensities, ranging from positive to negative stains.

Conclusion

Pancreaticoduodenectomy is the most effective treatment for ZES. Long-term follow-up is essential for pulmonary NET G2 owing to the risk of distant metastasis and/or multiplicity. Moreover, the variability of menin IHC in MEN1-related tumors may indicate the pattern of tumor formation rather than the diagnostic utility of menin in MEN1.

Radiological Features of Zollinger–Ellison Syndrome: A Report of Two Cases

Hypersecretion of gastrin from duodenal or pancreatic gastrinomas results in a rare clinical entity called Zollinger–Ellison syndrome (ZES). It mostly presents with abdominal pain and diarrhea. ZES may be sporadic or occur in association with multiple endocrine neoplasia type 1. Usually, ZES manifests between 20 and 50 years.

We report two cases of patients who presented with abdominal pain, vomiting, watery diarrhea, and significant weight loss.

Metastatic Patterns of Duodenopancreatic Neuroendocrine Tumors in Patients With Multiple Endocrine Neoplasia Type 1

Patients with multiple endocrine neoplasia 1 syndrome (MEN1) often develop multifocal duodenopancreatic neuroendocrine tumors (dpNETs). Nonfunctional pancreatic neuroendocrine tumors (PanNETs) and duodenal gastrinomas are the most frequent origins of metastasis. Current guidelines recommend surgery based on tumor functionality, size ≥2 cm, grade or presence of lymph node metastases. However, in case of multiple primary tumors it is often unknown which specific tumor metastasized. This study aims to unravel the relationship between primary dpNETs and metastases in patients with MEN1 by studying endocrine differentiation. First, it was shown that expression of the endocrine differentiation markers ARX and PDX1 was concordant in 18 unifocal sporadic neuroendocrine tumors (NETs) and matched metastases. Thereafter, ARX, PDX1, Ki67 and gastrin expression, and the presence of alternative lengthening of telomeres were determined in 137 microscopic and macroscopic dpNETs and 36 matched metastases in 10 patients with MEN1. ARX and PDX1 H-score clustering was performed to infer relatedness. For patients with multiple metastases, similar intrametastases transcription factor expression suggests that most metastases (29/32) originated from a single NET of origin, while few patients may have multiple metastatic primary NETs. In 6 patients with MEN1 and hypergastrinemia, periduodenopancreatic lymph node metastases expressed gastrin, and clustered with minute duodenal gastrinomas, not with larger PanNETs. PanNET metastases often clustered with high grade or alternative lengthening of telomeres-positive primary tumors. In conclusion, for patients with MEN1-related hypergastrinemia and PanNETs, a duodenal origin of periduodenopancreatic lymph node metastases should be considered, even when current conventional and functional imaging studies do not reveal duodenal tumors preoperatively.

Diagnosis and Management of Gastrointestinal Neuroendocrine Neoplasms

The latest WHO classification cleanly divides gastrointestinal neuroendocrine neoplasms into neuroendocrine tumor (NET; well-differentiated, any grade) and neuroendocrine carcinoma (NEC; poorly differentiated, high-grade by definition), along with mixed neuroendocrine-non-neuroendocrine neoplasms. NECs are always aggressive, with multiple mutations; they are treated with chemotherapy. NETs have widely different presentations, behavior, and management depending on site of origin. Esophageal examples are vanishingly rare. Most gastric and appendiceal tumors are indolent, as are many colonic and rectal tumors. The duodenum is home to some unusual variants of NET, and jejunal/ileal NETs frequently metastasize, which impacts their staging and clinical management.

Multiple Endocrine Neoplasia Type 1 and the Pancreas: Diagnosis and Treatment of Functioning and Non-Functioning Pancreatic and Duodenal Neuroendocrine Neoplasia within the MEN1 Syndrome - An International Consensus Statement

The better understanding of the biological behavior of multiple endocrine neoplasia type 1 (MEN1) organ manifestations and the increase in clinical experience warrant a revision of previously published guidelines. Duodenopancreatic neuroendocrine neoplasias (DP-NENs) are still the second most common manifestation in MEN1 and, besides NENs of the thymus, remain a leading cause of death. DP-NENs are thus of main interest in the effort to reevaluate recommendations for their diagnosis and treatment. Especially over the last 2 years, more clinical experience has documented the follow-up of treated and untreated (natural-course) DP-NENs. It was the aim of the international consortium of experts in endocrinology, genetics, radiology, surgery, gastroenterology, and oncology to systematically review the literature and to present a consensus statement based on the highest levels of evidence. Reviewing the literature published over the past decade, the focus was on the diagnosis of F- and NF-DP-NENs within the MEN1 syndrome in an effort to further standardize and improve treatment and follow-up, as well as to establish a "logbook" for the diagnosis and treatment of DP-NENs. This shall help further reduce complications and improve long-term treatment results in these rare tumors. The following international consensus statement builds upon the previously published guidelines of 2001 and 2012 and attempts to supplement the recommendations issued by various national and international societies.

[Inherited tumor syndromes of gastroenteropancreatic and thoracic neuroendocrine neoplasms]

About 5% of gastroenteropancreatic and thoracic neuroendocrine neoplasms (NENs) arise in the context of an inherited tumour syndrome. The two most frequent syndromes are: multiple endocrine neoplasia type 1 (MEN1), associated with a large spectrum of endocrine and non endocrine tumours, including duodenopancreatic, thymic and bronchial NENs, and the von Hippel-Lindau syndrome VHL, associated with pancreatic NENs. Two inherited syndromes have a low incidence of NENs: neurofibromatosis type 1 (NF1), associated with duodenal somatostatinomas, and tuberous sclerosis (TSC), associated with pancreatic NENs. Two rare syndromes have a high incidence of NENs: multiple endocrine neoplasia type 4 (MEN4), with a tumour spectrum similar to that of MEN1, and glucagon cell hyperplasia neoplasia (GCHN), involving only the pancreas. It is likely that other syndromes remain to be characterized, especially in familial small-intestinal NENs. The diagnosis is usually raised because of the suggestive clinical setting: young age at diagnosis, multiple tumours in multiple organs, familial history. Except in VHL and NF1, tumours themselves do not show specific pathological features; they usually are well differentiated and of low histological grade; their prognosis is good, except for MEN1-associated thymic NENs. The most suggestive pathological feature is their combination with various endocrine and/or non endocrine lesions in the adjacent tissue. Pathological examination is important, for a correct diagnosis and for an accurate management of the patients and their families, who must be referred to expert centers.

Contemporary surgical management of the Zollinger-Ellison syndrome in multiple endocrine neoplasia type 1

About 30% of patients with MEN1 develop a Zollinger-Ellison syndrome. Meanwhile it is well established that the causative gastrinomas are almost exclusively localized in the duodenum and not in the pancreas, MEN1 gastrinomas occur multicentric and are associated with hyperplastic gastrin cell lesions and tiny gastrin-producing micro tumors in contrast to sporadic duodenal gastrinomas. Regardless of the high prevalence of early lymphatic metastases, the survival is generally good with an aggressive course of disease in only about 20% of patients. Symptoms can be controlled medically. The indication, timing, type, and extent of surgery are highly controversial and are discussed in detail in this article by a thorough and critical review of literature. More radical procedures, like partial pancreaticoduodenectomy, are weighed against less aggressive local excision of gastrinomas and the pros and cons of both approaches are discussed in terms of long-term morbidity, biochemical cure, and survival.

Surgical management of Zollinger-Ellison syndrome: Classical considerations and current controversies

Zollinger-Ellison syndrome (ZES) is characterized by gastric acid hypersecretion causing severe recurrent acid-related peptic disease. Excessive secretion of gastrin can now be effectively controlled with powerful proton pump inhibitors, but surgical management to control gastrinoma itself remains controversial. Based on a thorough literature review, we design a surgical algorithm for ZES and list some significant consensus findings and recommendations: (1) For sporadic ZES, surgery should be routinely undertaken as early as possible not only for patients with a precisely localized diagnosis but also for those with negative imaging findings. The surgical approach for sporadic ZES depends on the lesion location (including the duodenum, pancreas, lymph nodes, hepatobiliary tract, stomach, and some extremely rare sites such as the ovaries, heart, omentum, and jejunum). Intraoperative liver exploration and lymphadenectomy should be routinely performed; (2) For multiple endocrine neoplasia type 1-related ZES (MEN1/ZES), surgery should not be performed routinely except for lesions > 2 cm. An attempt to perform radical resection (pancreaticoduodenectomy followed by lymphadenectomy) can be made. The ameliorating effect of parathyroid surgery should be considered, and parathyroidectomy should be performed first before any abdominal surgery for ZES; and (3) For hepatic metastatic disease, hepatic resection should be routinely performed. Currently, liver transplantation is still considered an investigational therapeutic approach for ZES. Well-designed prospective studies are desperately needed to further verify and modify the current considerations.

Current and emerging therapies for PNETs in patients with or without MEN1

Pancreatic neuroendocrine tumours (PNETs) might occur as a non-familial isolated endocrinopathy or as part of a complex hereditary syndrome, such as multiple endocrine neoplasia type 1 (MEN1). MEN1 is an autosomal dominant disorder characterized by the combined occurrence of PNETs with tumours of the parathyroids and anterior pituitary. Treatments for primary PNETs include surgery. Treatments for non-resectable PNETs and metastases include biotherapy (for example, somatostatin analogues, inhibitors of receptors and monoclonal antibodies), chemotherapy and radiological therapy. All these treatments are effective for PNETs in patients without MEN1; however, there is a scarcity of clinical trials reporting the efficacy of the same treatments of PNETs in patients with MEN1. Treatment of PNETs in patients with MEN1 is challenging owing to the concomitant development of other tumours, which might have metastasized. In recent years, preclinical studies have identified potential new therapeutic targets for treating MEN1-associated neuroendocrine tumours (including PNETs), and these include epigenetic modification, the β-catenin-wingless (WNT) pathway, Hedgehog signalling, somatostatin receptors and MEN1 gene replacement therapy. This Review discusses these advances.

New Genetics and Genomic Data on Pancreatic Neuroendocrine Tumors: Implications for Diagnosis, Treatment, and Targeted Therapies

The recent findings on the roles of death-associated protein 6/α-thalassemia/mental retardation X-linked (DAXX/ATRX) in the development of pancreatic neuroendocrine tumors (PanNETs) have led to major advances in the molecular understanding of these rare tumors and open up completely new therapeutic windows. This overview aims at giving a simplified view on these findings and their possible therapeutic implications. The importance of epigenetic changes in PanNET is also underlined by recent findings of a cross-species study on microRNA (miRNA) and messenger RNA (mRNA) profiles in PanNETs.

Synchronous Peripancreatic Lymph Node Gastrinoma and Gastric Neuroendocrine Tumor Type 2

A 34-year-old man was referred to our hospital with gastric polypoid lesions and biopsy-confirmed neuroendocrine tumor (NET). Computed tomography (CT) revealed a 3×3.5×8-cm retroperitoneal mass behind the pancreas, with multiple hepatic metastases. His serum gastrin level was elevated to 1,396 pg/mL. We performed a wedge resection of the stomach, a right hemi-hepatectomy, and a retroperitoneal mass excision. After careful review of the clinical, radiological, histopathological, and immunohistochemical findings, peripancreatic gastrinoma, and synchronous gastric NET were ultimately diagnosed. We reviewed a CT scan that had been performed 6 years previously after surgery for a duodenal perforation. There was no evidence of gastric or hepatic lesions, but the retroperitoneal mass was present at the same site. Had gastrinoma been detected earlier, our patient could have been cured using less invasive treatment. This case demonstrates how important it is to consider Zollinger-Ellison syndrome in patients with a recurrent or aggressive ulcer.

Duodenal neuroendocrine tumors: retrospective evaluation of CT imaging features and pattern of metastatic disease on dual-phase MDCT with pathologic correlation

PURPOSE

The purpose of the study is to evaluate the CT appearance and pattern of metastatic disease of patients with surgically resected well-differentiated duodenal neuroendocrine tumors who underwent pre-operative dual-phase CT.

METHODS

Clinical and pathologic records and CT images of 28 patients (average age 58.0 years) following Whipple procedure were retrospectively reviewed. The size, morphology (polypoid, intraluminal mass or wall thickening, intramural mass), location, CT attenuation in the arterial and venous phases, and the presence of lymph node or liver metastases were recorded.

RESULTS

On CT, 19 patients (67.8%) had neuroendocrine tumors manifested as polypoid or intraluminal masses (38 lesions, multiple tumors in 3 patients), 4 patients (14.3%) had tumors manifested as wall thickening or intramural masses, and in 5 patients (17.9%), the primary tumor was not visualized. Lesions not seen at CT were less than 0.8 cm on pathologic diagnosis. The mean size of polypoid tumors on CT was 1.2 cm (range 0.3-3.8 cm); 24 tumors were 1.0 cm or smaller, and 14 tumors were larger than 1.0 cm. Most lesions were hypervascular in the arterial phase (19/23 patients) with an increase in tumor enhancement in the venous phase in 14 patients (60.9%), decrease in enhancement in 7 patients (30.4%), and no change in enhancement in 2 patients (8.7%). Thirteen patients (46.4%) had metastatic disease from carcinoid tumor, most commonly regional enhancing lymphadenopathy.

CONCLUSION

Duodenal carcinoid tumors commonly appear as an enhancing mass in either the arterial or venous phases. If a primary tumor is not seen in the duodenum, adjacent enhancing lymphadenopathy can be a clue to the presence of a duodenal carcinoid tumor.

Multiple Endocrine Neoplasia: A Genetically Diverse Group of Familial Tumor Syndromes

Multiple endocrine neoplasia (MEN) syndrome is a familial cancer syndrome characterized by neuroendocrine tumors. The syndrome encompasses four major subtypes: MEN1, MEN2A, MEN2B, and MEN4. MEN1 is caused by mutations in the MEN1 gene, MEN2A and MEN2B are caused by mutations in RET, and MEN4 is caused by mutations in CDKNB1. All are inherited in an autosomal dominant pattern, but de novo cases do arise. While all subtypes are associated with neuroendocrine tumors, each has characteristic organ involvement. Identifying patients with the syndrome can aid in proper screening and treatment.

Controversies in surgery for multiple endocrine neoplasia type 1-associated Zollinger–Ellison syndrome

Zollinger–Ellison syndrome (ZES) is a common manifestation of multiple endocrine neoplasia type 1 (MEN1). At least 90% of MEN1-ZES patients have multiple duodenal gastrinomas, making the duodenum the target organ of ZES. The indication and the timing of surgery in MEN1-ZES is controversial, since there is yet no parameter that indicates an aggressive course of disease and long-term survival is generally good. An imageable, most likely nonfunctioning pancreatic neuroendocrine neoplasm (pNEN) >1–2 cm seems to be a good surrogate parameter to indicate surgery in order to prevent distant metastatic pNEN disease, although some groups indicate surgery at the time of biochemical ZES evidence. The optimal surgical procedure is also controversial. Different strategies encomprise local excision via duodenotomy with or without distal pancreatic resection and regional lymphadenectomy to partial pancreaticoduodenectomy. At present, the timing and type of surgery for MEN1-ZES should be individualized according to patient’s characteristics and preference.

Primary lymph node gastrinoma: 2 cases and a review of the literature

INTRODUCTION

Gastrinoma is a rare tumour of the diffuse neuroendocrine system with the primary invariability located within the duodenum or pancreas. Numerous authors have described gastrinoma apparently isolated to peripancreatic lymph nodes, following exhaustive radiological and operative localisation and examination.

METHOD

Two cases of apparent primary lymph node gastrinoma seen in our institution are presented, along with a literature review including 58 other presented cases.

RESULTS

On prolonged follow-up up to 131 months, 34 patients have remained in remission supporting the diagnosis of primary lymph node gastrinoma. Occult primary disease, usually in the form of microduodenal tumours, have become evident in the remaining 24 cases.

CONCLUSION

The existence of primary lymph node gastrinoma is supported by many presented case studies, but long-term follow-up of all patients should occur in the expectation that occult primary disease will become apparent in some.

Genetics of pancreatic neuroendocrine tumors: implications for the clinic

Pancreatic neuroendocrine tumors (PanNETs) are a common and deadly neoplasm of the pancreas. Although the importance of genetic alterations in PanNETs has been known for many years, recent comprehensive sequencing studies have greatly expanded our knowledge of neuroendocrine tumorigenesis in the pancreas. These studies have identified specific cellular processes that are altered in PanNETs, highlighted alterations with prognostic implications, and pointed to pathways for targeted therapies. In this review, we will discuss the genetic alterations that play a key role in PanNET tumorigenesis, with a specific focus on those alterations with the potential to change the way patients with these neoplasms are diagnosed and treated.

Hyperplasia to neoplasia sequence of duodenal and pancreatic neuroendocrine diseases and pseudohyperplasia of the PP-cells in the pancreas

Hyperplastic changes of the neuroendocrine cell system may have the potential to evolve into neoplastic diseases. This is particularly the case in the setting of genetically determined and hereditary neuroendocrine tumor syndromes such as MEN1. The review discusses the MEN1-associated hyperplasia-neoplasia sequence in the development of gastrinomas in the duodenum and glucagon-producing tumors in the pancreas. It also presents other newly described diseases (e.g., glucagon cell adenomatosis and insulinomatosis) in which the tumors are (or most likely) also preceded by islet cell hyperplasia. Finally, the pseudohyperplasia of PP-rich islets in the pancreatic head is defined as a physiologic condition clearly differing from other hyperplastic-neoplastic neuroendocrine diseases.

Zollinger-Ellison syndrome: recent advances and controversies

PURPOSE OF REVIEW

To review the recent advances and current controversies in patients with Zollinger-Ellison syndrome (ZES).

RECENT FINDINGS

Recent advances in the management of ZES include: improved understanding of the pathogenesis of gastrinoma and pancreatic neuroendocrine tumors, new prognostic classification systems, new diagnostic algorithms, more sensitive localization studies, new treatment strategies including improved control of gastric acid secretion and role for surgery, and new approaches to patients with advanced disease. Controversies include: the best approach to a patient with hypergastrinemia suspected of possibly having ZES, the appropriate gastrin assay to use, the role of surgery in patients with ZES, especially those with multiple endocrine neoplasia type 1, and the precise order of therapeutic modalities in the treatment of patients with advanced disease.

SUMMARY

This review updates clinicians regarding important advances and controversies required to optimally diagnose and manage patients with ZES.

Pathologic staging of pancreatic, ampullary, biliary, and gallbladder cancers: pitfalls and practical limitations of the current AJCC/UICC TNM staging system and opportunities for improvement

Tumors of the ampulla-pancreatobiliary tract are encountered increasingly; however, their staging can be highly challenging due to lack of familiarity. In this review article, the various issues encountered in staging of these tumors at the pathologic level are evaluated and possible solutions for daily practice as well as potential improvements for future staging protocols are discussed. While N-stage parameters have now been well established (the number of lymph nodes required in pancreatoduodenectomies is 12), the T-staging has several issues: for the pancreas, the discovery of small cancers arising in intraductal papillary mucinous neoplasms (IPMNs) and mucinous cystic neoplasms (MCNs) necessitates the creation of substages of T1 (as T1a, b, and c); lack of proper definition of "peripancreatic soft tissue" and "common bile duct involvement" (as to which part is meant) makes T3 highly subjective. Increasing resectability of main vessels (portal vein) brings the need to redefine a "T" for such cases. For the ampulla, due to factors like anatomic complexity of the region and the under-appreciation of three-dimensional spread of the tumors in this area (in particular, the frequent extension into periduodenal soft tissues and duodenal serosa, which are not addressed in the current system and which require specific grossing approaches to document), the current T-staging lacks reproducibility and clinical relevance, and therefore, major revisions are needed. Recently proposed refined definition and site-specific subclassification of ampullary tumors highlight the areas for improvement. For the extrahepatic bile ducts, the staging schemes that use the depth of invasion may be more practical to circumvent the inconsistencies in the histologic layering of the ducts; better definition of terms like "periductal spread" is needed. For the gallbladder, since many gallbladder cancers are "unapparent" (found in clinically and grossly unsuspected cholecystectomies), establishing proper grossing protocols and adequate sampling are crucial. Since the gallbladder does not have the distinct layering of the other gastrointestinal organs, the definitions of Tis/T1a/T1b lack practicality, and therefore, "early gallbladder carcinoma" category proposed in high-risk regions may have to be recognized instead. Involvement of the Rokitansky-Aschoff sinuses should be a part of the evaluation and management of these early gallbladder cancers; for advanced cancers, documentation of hepatic versus serosal involvement is necessary. In summary, T-staging of ampulla-pancreatobiliary tract tumors has many challenges. Proper grossing and appreciation of histo-anatomic subtleties of this region are crucial in addressing these issues and achieving more applicable and clinically relevant staging systems in the future.

Classification and pathology of gastroenteropancreatic neuroendocrine neoplasms

Gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) are composed of cells with a neuroendocrine phenotype. The old and the new WHO classifications distinguish between well-differentiated and poorly differentiated neoplasms. All well-differentiated neoplasms, regardless of whether they behave benignly or develop metastases, will be called neuroendocrine tumours (NETs), and graded G1 (Ki67 <2%) or G2 (Ki67 2-20%). All poorly differentiated neoplasms will be termed neuroendocrine carcinomas (NECs) and graded G3 (Ki67 >20%). To stratify the GEP-NETs and GEP-NECs regarding their prognosis, they are now further classified according to TNM-stage systems that were recently proposed by the European Neuroendocrine Tumour Society (ENETS) and the AJCC/UICC. In the light of these criteria the pathology and biology of the various NETs and NECs of the gastrointestinal tract (including the oesophagus) and the pancreas are reviewed.

Pathology of gastrointestinal disorders

Nonneoplastic and neoplastic proliferative lesions of endocrine cells of the gastrointestinal tract are detailed. A multistep continuum from hyperplasia, dysplasia to neoplasia is identified for histamine-producing enterochromaffin-like (ECL) cells of the gastric corpus. Most gastric neuroendocrine tumors (NETs) are silent and composed by ECL cells, the second most frequent neuroendocrine neoplasms being the high-grade neuroendocrine carcinoma (NEC). In the duodenum, preneoplastic lesions are similarly described for gastrin (G) and somatostatin (D) cells. G-cell NETs are the most frequent neuroendocrine tumors of the duodenum, either functioning or nonfunctioning, followed by D-cell NETs and gangliocytic paraganglioma (GCP). No systematic definition of nonneoplastic lesions exists for endocrine cells of the ileum, appendix, and colon-rectum. The most frequent ileal NETs are serotonin-producing enterochromaffin (EC)-cell NETs (classic carcinoid), associating with functional syndrome only in presence of liver metastases. Neoplasms are usually larger in the colon as compared with the small lesions observed in the rectum. High-grade NECs are observed in the colon and rectum-sigmoid, often associate with nonendocrine neoplastic components, and fare an aggressive course with poor outcome and short survival.

Carcinoids and high-grade neuroendocrine carcinomas of the ampulla of vater: a comparative analysis of 139 cases from the surveillance, epidemiology, and end results program-a population based study

CONTEXT

Neuroendocrine tumors of the ampulla of Vater constitute a heterogeneous group of neoplasms clinically and morphologically. Because they are rare, little is known about their demographics and biologic behavior.

OBJECTIVE

To analyze the demographics and the 5- and 10-year relative survival rates of 139 patients with carcinoid tumors and high-grade neuroendocrine carcinomas of the ampulla.

DESIGN

Using data from National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) Program from 1973 to 2006, we analyzed the demographics, morphology, and survival of patients with carcinoids and neuroendocrine carcinomas of the ampulla.

RESULTS

SEER recorded 6081 cases of malignant neoplasms of the ampulla, of which 82 were carcinoid tumors and 57 were high-grade neuroendocrine carcinomas. Of these 57, 42 were neuroendocrine carcinomas, not otherwise specified; 9 were small cell carcinomas; and 6 were large cell neuroendocrine carcinomas. The incidence was higher in men than in women. Patients with carcinoid tumors were younger (mean age, 61.6 years) than those with high-grade neuroendocrine carcinomas (mean age, 67.5 years). Carcinoid tumors were smaller than high-grade neuroendocrine carcinomas. The frequency of lymph node metastasis was 28.5% for carcinoid tumors and 62% for high-grade neuroendocrine carcinomas. The 5- and 10-year relative survival rates of patients with carcinoid tumors were 82% and 71%, respectively. The 5- and 10-year relative survival rate of patients with high-grade neuroendocrine carcinomas was 15.7%.

CONCLUSIONS

Carcinoids of the ampulla of Vater are relatively rare. Carcinoids and high-grade neuroendocrine carcinomas of the ampulla are biologically and clinically similar to these tumors arising in other sites. Carcinoids were smaller and metastasized less frequently than high-grade neuroendocrine carcinomas.

Neuroendocrine tumors of the small bowels are on the rise: Early aspects and management

Neuroendocrine tumors of the small bowel are on the rise. In the US they have increased by 300%-500% in the last 35 years. At the same time their prognosis is much improved. Today, most neuroendocrine tumors (NETs) of the duodenum are detected "incidentally" and therefore recognized at an early stage. Duodenal NETs which are well differentiated, not larger than 10 mm and limited to the mucosa/submucosa can be endoscopically resected. The management of duodenal NETs ranging between 10 and 20 mm needs an interdisciplinary discussion. Endoscopic ultrasound is the method of choice to determine tumor size and depth of infiltration. Surgery is recommended for well-differentiated duodenal NET tumors greater than 20 mm, for localized sporadic gastrinomas (of any size) and for localized poorly differentiated NE cancers. Surgery is recommended for any ileal NET. Advanced ileal NETs with a carcinoid syndrome are treated with long-acting somatostatin analogs. This treatment significantly improves (progression-free) survival in patients with metastatic NETs of the ileum. For optimal NET management, tumor biology, type, localization and stage of the neoplasm, as well as the patient's individual circumstances have to be taken into account.

Asymptomatic children with multiple endocrine neoplasia type 1 mutations may harbor nonfunctioning pancreatic neuroendocrine tumors

CONTEXT

Multiple endocrine neoplasia type 1 (MEN1) is characterized by the occurrence of parathyroid, pituitary, and pancreatic tumors. MEN1, an autosomal dominant disorder, has a high degree of penetrance, such that more than 95% of patients develop clinical manifestations by the fifth decade, although this is lower at approximately 50% by age 20 yr. However, the lower penetrance in the younger group, which is based on detecting hormone-secreting tumors, may be an underestimate because patients may have nonfunctioning tumors and be asymptomatic.

OBJECTIVE

The aim of the study was to evaluate the occurrence of nonfunctioning pancreatic neuroendocrine tumors in asymptomatic children with MEN1.

PATIENTS

Twelve asymptomatic Northern European children, aged 6 to 16 yr, who were known to have MEN1 mutations were studied.

RESULTS

Two asymptomatic children, who were aged 12 and 14 yr, had normal plasma fasting gastrointestinal hormones and were found to have nonfunctioning pancreatic neuroendocrine tumors that were more than 2 cm in size. Surgery and immunostaining revealed that the tumors did not have significant expression of gastrointestinal hormones but did contain chromogranin A and synaptophysin, features consistent with those of nonfunctioning pancreatic neuroendocrine tumors. The tumors had a loss of menin expression. The 14 yr old also had primary hyperparathyroidism and a microprolactinoma, and the 12 yr old had a nonfunctioning pituitary microadenoma. Three other children had primary hyperparathyroidism and a microprolactinoma.

CONCLUSION

Nonfunctioning pancreatic neuroendocrine tumors may occur in asymptomatic children with MEN1 mutations, and screening for such enteropancreatic tumors in MEN1 children should be considered earlier than the age of 20 yr, as is currently recommended by the international guidelines.

Treatment strategies for Zollinger-Ellison syndrome

BACKGROUND

Zollinger-Ellison syndrome (ZES) is a rare disorder caused by tumor secretion of the hormone gastrin, which results in gastric acid hypersecretion and secondarily complicated peptic ulcer and diarrhea. Until the development of H(2)-receptor antagonists and later proton pump inhibitors (PPIs), the disease was virulent, often associated with ulcer-related mortality, and the mainstay of treatment was total gastrectomy.

OBJECTIVE

To evaluate current approaches to diagnosis and therapy, focusing on the role of PPIs.

METHODS

An extensive literature search through PubMed using the search term 'Zollinger-Ellison syndrome' from 1964 to the present was performed. Primary articles were identified, and pertinent articles obtained from the reference lists were also examined.

RESULTS/CONCLUSIONS

The clinical manifestations of ZES are well described, but overlaps with other more common disorders delay diagnosis. The use of abdominal imaging with somatostatin receptor scintigraphy and endoscopic ultrasound has improved tumor staging. PPI therapy is remarkably effective in controlling gastric acid hypersecretion, thereby reducing morbidity and potential mortality of this syndrome. The dose of drug necessary to control symptoms is highly variable but, even when used in high doses for prolonged periods of time, the disease remained controlled with very few drug-related side effects.