ECL cell tumor and poorly differentiated endocrine carcinoma of the stomach: prognostic evaluation by pathological analysis

Long-Term Proton Pump Inhibitor-Acid Suppressive Treatment Can Cause Vitamin B12 Deficiency in Zollinger-Ellison Syndrome (ZES) Patients

Whether the long-term treatment of patients with proton pump inhibitors (PPIs) with different diseases [GERD, Zollinger-Ellison syndrome (ZES), etc.] can result in vitamin B12 (VB12) deficiency is controversial. In this study, in 175 patients undergoing long-term ZES treatment with anti-acid therapies, drug-induced control acid secretory rates were correlated with the presence/absence of VB12 deficiency, determined by assessing serum VB12 levels, measurements of VB12 body stores (blood methylmalonic acid (MMA) and total homocysteine[tHYC]), and other features of ZES. After a mean of 10.2 yrs. of any acid treatment (5.6 yrs. with PPIs), 21% had VB12 deficiency with significantly lower serum and body VB12 levels (p < 0.0001). The presence of VB12 deficiency did not correlate with any feature of ZES but was associated with a 12-fold lower acid control rate, a 2-fold higher acid control pH (6.4 vs. 3.7), and acid control secretory rates below those required for the activation of pepsin (pH > 3.5). Over a 5-yr period, the patients with VB12 deficiency had a higher rate of achlorhydria (73% vs. 24%) and a lower rate of normal acid secretion (0% vs. 49%). In conclusion, in ZES patients, chronic long-term PPI treatment results in marked acid hyposecretion, resulting in decreased serum VB12 levels and decreased VB12-body stores, which can result in VB12 deficiency.

Gastric neuroendocrine neoplasms

Gastric neuroendocrine neoplasms (gNENs) display peculiar site-specific features among all NENs. Their incidence and prevalence have been rising in the past few decades. gNENs comprise gastric neuroendocrine carcinomas (gNECs) and gastric neuroendocrine tumours (gNETs), the latter further classified into three types. Type I anatype II gNETs are gastrin-dependent and develop in chronic atrophic gastritis and as part of Zollinger-Ellison syndrome within a multiple endocrine neoplasia type 1 syndrome (MEN1), respectively. Type III or sporadic gNETs develop in the absence of hypergastrinaemia and in the context of a near-normal or inflamed gastric mucosa. gNECs can also develop in the context of variable atrophic, relatively normal or inflamed gastric mucosa. Each gNEN type has different clinical characteristics and requires a different multidisciplinary approach in expert dedicated centres. Type I gNETs are managed mainly by endoscopy or surgery, whereas the treatment of type II gNETs largely depends on the management of the concomitant MEN1. Type III gNETs may require both locoregional approaches and systemic treatments; NECs are often metastatic and therefore require systemic treatment. Specific data regarding the systemic treatment of gNENs are lacking and are derived from the treatment of intestinal NETs and NECs. An enhanced understanding of molecular and clinical pathophysiology is needed to improve the management and outcomes of patients' gNETs.

Therapeutic Challenges for Gastric Neuroendocrine Neoplasms: Take It or Leave It?

Background and Objectives: Gastric neuroendocrine neoplasms (gNENs) represent rare but increasingly recognized tumors. They are distinguished into three main clinical types (type-1, type-2, and type-3) according to gastrin level and at histological evaluation in well-differentiated G1, G2, or G3 lesions, as well as poorly-differentiated lesions. Small type-1 and type-2 neoplasms with low proliferation indices demonstrated excellent survival without progression during an extended follow-up period, and for these reasons, active endoscopic observation or endoscopic resection are feasible options. On the other hand, surgery is the treatment of choice for more aggressive type-3, G3, or infiltrating neoplasms. The present study aims to comprehensively review and compare the available therapeutic strategies for gNENs. Materials and Methods: A computerized literature search was performed using relevant keywords to identify all of the pertinent articles with particular attention to gNEN endoscopic treatment. Results: In recent years, different endoscopic resective techniques (such as endoscopic mucosal dissection, modified endoscopic mucosal resection, and endoscopic full-thickness resection) have been developed, showing a high rate of complete resection for advanced and more aggressive lesions. Conclusions: Overall, gNENs represent a heterogeneous group of lesions with varying behavior which require personalized management. The non-operative approach for small type-1 gNENs seems to be feasible and should be promoted. A step-up approach with minimally invasive endoscopic therapies might be proposed, particularly for type-1 gNEN. On the other hand, it is important to recognize the negative prognostic factors in order to identify those rare cases requiring more aggressive approaches. A possible therapeutic algorithm for localized gNEN management is provided.

The Morphologic Spectrum of Gastric Type 1 Enterochromaffin-Like Cell Neuroendocrine Tumors

Although most well-differentiated gastric neuroendocrine tumors (gNETs) arise from enterochromaffin-like (ECL) cells in patients with autoimmune metaplastic atrophic gastritis (AMAG), the morphologic spectrum of these type 1 ECL-cell gNETs is not well defined. The extent of metaplastic progression in the background mucosa of AMAG patients with gNETs is likewise unclear. Here we report the histomorphology of 226 gNETs, including 214 type 1 gNETs (78 cases from 50 AMAG patients) pooled from a population with high AMAG prevalence. Most type 1 gNETs were ≤1.0 cm, of low grade, and multifocal, consistent with the results of previous reports. However, a high proportion (70/214, 33%) displayed unusual gNET morphologies not previously appreciated in AMAG patients. Unlike other type 1 gNETs with conventional neuroendocrine tumor morphologies, unconventional type 1 gNETs displayed cribriform networks of atrophic cells embedded within myxoid matrix (secretory-cribriform variant, 59%), sheets of deceptively bland discohesive cells resembling inflammatory infiltrates (lymphoplasmacytoid variant, 31%), or wreath-like arrangements of columnar cells wrapped around collagenous cores (pseudopapillary variant, 14%). Another unusual feature was that unconventional gNETs grew laterally within the mucosa (50/70, 71%) and were only rarely sampled from the submucosa (3/70, 4%). These features also differed from the conspicuous radial nodules (99/135, 73%) and frequent submucosal involvement (57/135, 42%) observed for conventional gNETs (P < .0001). Irrespective of morphology, type 1 gNETs were nearly always detected at first AMAG diagnosis (45/50, 90%) and tended to persist thereafter (34/43, 79%), despite similar clinical symptoms and laboratory values between AMAG patients with gNETs and those without. However, unlike AMAG patients without gNETs (n = 50), the background mucosa in patients with gNETs (n = 50) had already progressed to the morphologic equivalent of end-stage metaplasia (P < .0001). This included diffuse loss of parietal cells (92% vs 52%), complete intestinal metaplasia (82% vs 40%), and pancreatic metaplasia (56% vs 6%). Thus, type 1 ECL-cell gNETs are morphologically heterogeneous with a high prevalence of unconventional gNET morphologies. They tend to present silently at first AMAG diagnosis as multifocal lesions that persist within fields of mature metaplasia.

Practice patterns for reporting digestive system neuroendocrine neoplasms: results from a large, comprehensive international survey

AIMS

Criteria for the interpretation of digestive system neuroendocrine neoplasms (NENs) continue to evolve. Although there are some literature recommendations regarding workup and diagnosis of these lesions, different practice patterns exist among pathologists when signing out these specimens. The aim of this study was to assess practice trends among pathologists worldwide when reporting these neoplasms.

METHODS AND RESULTS

We created an online survey with multiple questions pertaining to digestive NENs. The results were analysed based on type of practice setting, years of sign-out experience, and practice location. Respondents included 384 practicing pathologists: 70% academic, 30% private practice; 63% gastrointestinal (GI) pathology-subspecialised, 37% not; 39% North American, 42% European, 19% others; 45% with ≤10 years in practice; 55% with >10 years. Some question responses were chosen by the majority (e.g. 85% use both mitotic count and Ki67 index for grading NENs, 82% complete a synoptic, and Ki67 stain even for small incidental appendiceal neuroendocrine tumours [NETs], and 96% utilize the diagnosis of grade 3 NET). However, some questions showed varying responses, including counting mitotic figures, Ki67 stain interpretation, and pancreatic grade 3 NEN workup. Pathologists also had some variability in interpreting regional metastatic foci of small bowel NETs and in choosing blocks for Ki67 staining in multifocal lesions.

CONCLUSION

There existed scenarios wherein practice patterns varied despite recommendations in the literature, and there were also scenarios lacking clear guidelines wherein pathologists used varying judgement. This survey highlights current key grey areas in digestive system NEN evaluation, leading to variation in practice patterns.

Liver transplantation in gastroenteropancreatic neuroendocrine tumors

Neuroendocrine tumors are part of a heterogeneous group of tumors located in organs such as the gastrointestinal tract (GIT), lungs, thymus, thyroid, and adrenal glands. The most prevalent sites are the small intestine, cecal appendix, and pancreas. More than 50% of these tumors are associated with metastases at the time of diagnosis. Neuroendocrine tumors are classified according to the degree of cell differentiation and the histopathological proliferation index of the lesion. Neuroendocrine tumors can be well differentiated or poorly differentiated. G3 tumors are characterized by Ki-67 expression greater than 20% and can be either well differentiated (G3 NET) or poorly differentiated (G3 NEC). Neuroendocrine carcinoma (NEC G3) is subdivided into small-cell and large-cell types. When neuroendocrine tumors present clinical and compressive symptoms, carcinoid syndrome is evident. Carcinoid syndrome occurs when the tumor produces neuroendocrine mediators that cannot be metabolized by the liver due to either the size of the tumor or their secretion by the liver itself. Several therapeutic strategies have been described for the treatment of metastatic neuroendocrine tumors, including curative or palliative surgical approaches, peptide receptor radionuclide therapy, percutaneous therapy, systemic chemotherapy, and radiotherapy. Liver surgery is the only approach that can offer a cure for metastatic patients. Liver metastases must be completely resected, and in this context, orthotopic liver transplantation has gained prominence for yielding very promising outcomes in selected cases. The aim of this study is to review the literature on OLT as a form of treatment with curative intent for patients with gastroenteropancreatic neuroendocrine tumors with liver metastasis.

Quantitative characterization of duodenal gastrinoma autofluorescence using multiphoton microscopy

BACKGROUND

Duodenal gastrinomas (DGASTs) are neuroendocrine tumors that develop in the submucosa of the duodenum and produce the hormone gastrin. Surgical resection of DGASTs is complicated by the small size of these tumors and the tendency for them to develop diffusely in the duodenum. Endoscopic mucosal resection of DGASTs is an increasingly popular method for treating this disease due to its low complication rate but suffers from poor rates of pathologically negative margins. Multiphoton microscopy can capture high-resolution images of biological tissue with contrast generated from endogenous fluorescence (autofluorescence [AF]) through two-photon excited fluorescence (2PEF). Second harmonic generation is another popular method of generating image contrast with multiphoton microscopy (MPM) and is a light-scattering phenomenon that occurs predominantly from structures such as collagen in biological samples. Some molecules that contribute to AF change in abundance from processes related to the cancer disease process (e.g., metabolic changes, oxidative stress, and angiogenesis).

STUDY DESIGN/MATERIALS AND METHODS

MPM was used to image 12 separate patient samples of formalin-fixed and paraffin-embedded duodenal gastrinoma slides with a second-harmonic generation (SHG) channel and four 2PEF channels. The excitation and emission profiles of each 2PEF channel were tuned to capture signal dominated by distinct fluorophores with well-characterized fluorescent spectra and known connections to the physiologic changes that arise in cancerous tissue.

RESULTS

We found that there was a significant difference in the relative abundance of signal generated in the 2PEF channels for regions of DGASTs in comparison to the neighboring tissues of the duodenum. Data generated from texture feature extraction of the MPM images were used in linear discriminant analysis models to create classifiers for tumor versus all other tissue types before and after principal component analysis (PCA). PCA improved the classifier accuracy and reduced the number of features required to achieve maximum accuracy. The linear discriminant classifier after PCA distinguished between tumor and other tissue types with an accuracy of 90.6%-93.8%.

CONCLUSIONS

These results suggest that multiphoton microscopy 2PEF and SHG imaging is a promising label-free method for discriminating between DGASTs and normal duodenal tissue which has implications for future applications of in vivo assessment of resection margins with endoscopic MPM.

A Case of Gastric Glomus Tumor Misdiagnosed as Carcinoid Tumor

Glomus tumor is a rare mesenchymal tumor commonly located in the periphery of glomus bodies, such as the subungual regions (e.g., fingernails and toenails). Other locations include the forearm, wrist, or trunk. Even rare is when these tumors are found in the submucosa. In the stomach, it is commonly found at the gastric antrum. Gastric glomus tumors (GGTs) are often found incidentally after a presumption of other gastric tumors is diagnosed, such as gastrointestinal stromal tumors (GISTs) or carcinoid tumors. The variable clinical presentation of GGT and the fact that histology is the only way to confirm the diagnosis is what makes GGT such an elusive tumor. Our case is a patient that presented with weight loss and reflux. Esophagogastroduodenoscopy (EGD) and colonoscopy were done, and the diagnosis of carcinoid tumor was presumed. Preliminary pathology was suggestive of a diagnosis of carcinoid tumor. The patient eventually had a subtotal gastrectomy, and a biopsy with immunohistochemical staining of the specimen was received, finally confirming the diagnosis of a GGT.

Successful endoscopic resection of an unusually enlarged and pedunculated type I gastric carcinoid tumour

Three distinct gastric carcinoid (GC) tumour types have been described based on differing biological behaviour and prognoses. Type I GC tumours account for the vast majority (70%-80%), are associated with chronic atrophic gastritis and have a low metastatic potential. Type II carcinoid tumours are the least common (5%-10%), are related to Zollinger-Ellison syndrome and occur in relation to multiple neoplasia type I. Sporadic type III tumours (15%-25%) are the most aggressive type, are unrelated to gastrin over secretion and carry the worst prognosis. In this case report, we present a patient with longstanding gastroesophageal reflux disease (GERD) who presented with epigastric abdominal pain and tarry stools and was found to have a large gastric polyp on endoscopy. Despite current literature recommending surgical resection for larger GC tumours, endoscopic resection was successfully used to excise the tumour with pathology demonstrating complete resection with negative margins.

Gastric Neuroendocrine Tumors: Reappraisal of Type in Predicting Outcome

BACKGROUND

Type I gastric neuroendocrine tumors (GNETs) are typically managed either expectantly or endoscopically. In contrast, locoregional surgery has been recommended for patients with type III GNETs because of the risk of metastasis. This study aimed to identify predictors of outcome independent of type in a contemporary cohort of GNET patients.

METHODS

A single-institution retrospective cohort study of 121 patients with a pathologic diagnosis of primary GNET between January 2009 and June 2019 was performed. GNETs were designated as type 1 (n = 74) if atrophic gastritis was present, or as type III (n = 47) in the absence of atrophic gastritis. Demographic, clinical, and histopathologic factors were examined using Kaplan-Meier and multivariable Cox regression to assess the impact of various factors on recurrence and overall survival.

RESULTS

Median follow-up for the entire cohort was 62.7 months. While there was no difference in OS in patients with different GNET types (p = 0.10), higher tumor grade (p = 0.02) and presence of nodal or distant metastases (p = 0.02) predicted worse survival on multivariable analysis. Among type III GNET patients, those with small (< 0.5 cm), grade 1 lesions ("low-risk") were less likely to develop metastases (0% versus 33%, p < 0.01) and more likely to survive (100% versus 67%, p < 0.01) at 5 years.

CONCLUSIONS

Size and tumor grade predict recurrence and survival in patients with GNETs irrespective of type. Small, low-grade type III GNETs are associated with minimal risk of progression and may be managed accordingly.

Endoscopic Treatment of Gastric and Duodenal Neuroendocrine Tumors: Present and Future

Gastric and duodenal neuroendocrine tumors (NETs) are not common; however, there is an increase in the incidence due to increased use of endoscopy. Endoscopic treatment has been applied to treat small NET G1 in the stomach and duodenum. For the endoscopic treatment of NETs, it is necessary to evaluate tumor size, depth of invasion, and lymphatic and distant metastasis. This article will review the current knowledge concerning the endoscopic treatment of gastric and duodenal neuroendocrine tumors.

Is endoscopic resection appropriate for type 3 gastric neuroendocrine tumors? Retrospective multicenter study

BACKGROUND

Gastrectomy with lymphadenectomy is recommended for type 3 gastric neuroendocrine tumors (G-NETs). This study aimed to identify the risk factors for lymph node metastasis (LNM) arising from G-NETs to assess the suitability of endoscopic resection (ER).

METHODS

Nationwide clinicopathological data of patients with type 3 G-NETs who underwent surgery or ER were collected. A single pathologist graded the histological tumor specimens.

RESULTS

Among 176 cases from 53 institutions, 144 were eligible for analysis (90 NET-G1 and 54 NET-G2 grade, 8-mm median-size tumors). Of these, 63 patients had undergone ER (15 with additional surgeries). Histological data regarding LNM were available for 93 surgical patients. LNM was confirmed in 15 (16%) tumors and was correlated with tumor diameter, invasion depth, and tumor grade. LNM was negative in six tumors ≤5 mm, confined to the mucosa or submucosa, with a grade of G1, and without lymphovascular invasion, but the number of cases was too small to propose ER indications. Among 48 patients treated with ER alone, only one developed recurrence; no mortality was observed at follow-up, although many patients were classified with SM2/NET-G2/tumors >5 mm. This suggests that not all LNMs arising from small G-NETs are fatal.

CONCLUSION

Gastrectomy with lymphadenectomy for type 3 G-NETs is recommended on the basis of LNM. However, ER for type 3 G-NETs ≤10 mm, confined to the mucosa or submucosa, with a grade of G1 has shown excellent survival outcomes despite the risk of LNM, and therefore, could be an alternative treatment option.

Neuroendocrine neoplasms of the esophagus and stomach

Esophageal neuroendocrine neoplasms (E-NENs) are much rarer than other gastro-entero-pancreatic neuroendocrine neoplasms, the majority showing aggressive behavior with early dissemination and poor prognosis. Among E-NENs, exceptionally rare well differentiated neuroendocrine tumors (E-NET) and more frequent esophageal poorly differentiated neuroendocrine carcinomas (E-NEC) and mixed neuroendocrine-non neuroendocrine neoplasms (MiNEN) can be recognized. E-NECs usually exhibit a small cell morphology or mixed small and large cells. Esophageal MiNEN are composed of NEC component admixed with adenocarcinoma or squamous cell carcinoma. Gastric (G) NENs encompass a wide spectrum of entities ranging from indolent G-NETs to highly aggressive G-NECs and MiNENs. Among G-NETs, ECL-cell NETs are the most common and, although composed of histamine-producing cells, are a heterogeneous group of neoplastic proliferations showing different clinical and prognostic features depending on the patient’s clinico-pathological background including the morphology of the peri-tumoral mucosa, gastrin serum levels, presence or absence of antral G-cell hyperplasia, and presence or absence of MEN1 syndrome. In general, NET associated with hypergastrinemia show a better outcome than NET not associated with hypergastrinemia. G-NECs and MiNENs are aggressive neoplasms more frequently observed in males and associated with a dismal prognosis.

Clinicopathological characteristics and prognosis of 77 cases with type 3 gastric neuroendocrine tumours

BACKGROUND

For the rarity of type 3 gastric neuroendocrine tumours (g-NETs), their clinicopathological characteristics and prognosis are not well illustrated.

AIM

To describe the clinicopathological features and outcome of type 3 g-NETs in the Chinese population.

METHODS

Based on the 2019 WHO pathological classification, the clinicopathological characteristics and prognosis of patients with type 3 g-NETs in China were retrospectively analysed.

RESULTS

A total of 77 patients (55.8% of females) with type 3 g-NETs were analysed, with a median age of 48 years (range: 28-79 years). The tumours were mainly located in the gastric fundus/body (83.1%) and were mostly solitary (83.1%), with a median size of 1.5 cm (0.8-3.5 cm). Of these, there were 37 G1 tumours (48.1%), 31 G2 (40.3%), and 9 G3 (11.7%). Ten (13.0%) and 24 (31.2%) patients had lymph node and distant metastasis, respectively. In addition, type 3 g-NETs were heterogeneous. Compared with G1 NETs, G2 NETs had a higher lymph node metastasis rate, and G3 NETs had a higher distant metastasis rate. G1 and G2 NETs with stage I/II disease (33/68) received endoscopic treatment, and no tumour recurrence or tumour-related death was observed within a median follow-up time of 36 mo. Grade and distant metastasis were identified to be independent risk factors for prognosis in multivariable analysis.

CONCLUSION

Type 3 g-NETs are obviously heterogeneous, and the updated WHO 2019 pathological classification may be used to effectively evaluate their biological behaviors and prognosis. Also, endoscopic treatment should be considered for small (< 2 cm), low grade, superficial tumours.

Gastric neuroendocrine tumours from long-term proton pump inhibitor users are indolent tumours with good prognosis

AIMS

Proton pump inhibitors (PPIs) are among the most widely used medications in the United States. Most PPI users have persistent hypergastrinaemia during treatment. However, gastric neuroendocrine tumours diagnosed in long-term PPI users are rarely reported. Their clinicopathological features and prognosis are not characterised. It remains unclear whether or not they can be classified as Type III sporadic tumours.

METHODS AND RESULTS

We retrospectively characterised 66 gastric neuroendocrine tumours from patients without atrophic gastritis and gastrinoma from two tertiary care medical centres, including 38 tumours in patients who had used PPIs for at least 1 year and 28 tumours from patients without long-term PPI use (control group, Type III tumours). Compared to controls, tumours from long-term PPI users tended to be in the pT1-2 category (98% versus 79%, P = 0.09) and less often invaded the serosa (3% versus 18%, P = 0.08) or lymphovascular spaces (11% versus 32%, P = 0.06). Using Kaplan-Meier analysis, long-term PPI users had significantly longer overall survival than controls (P = 0.035). While three control patients developed distant metastasis and seven died, long-term PPI users were without distant metastasis (P = 0.06) or death (P = 0.002) during follow-up. However, five long-term PPI users developed additional gastric neuroendocrine tumour(s), while none of the controls did (P = 0.07).

CONCLUSIONS

Our results show that gastric neuroendocrine tumours of long-term PPI users are probably less aggressive compared to Type III sporadic tumours and have an indolent disease course. Our findings support the classification of gastric neuroendocrine tumours in long-term PPI users as a separate subtype.

Gastro-entero-pancreatic neuroendocrine neoplasia: The rules for non-operative management

Gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) with favorable pathological and clinical features may be considered as indolent lesions, and therefore be amenable to conservative management. According to the primary tumor site, different non-aggressive approaches, based on endoscopic resection or simple active surveillance, can be proposed to selected patients fulfilling specific criteria. Tumor size, Ki67 proliferative index and depth of invasion are markers that can be used in order to identify these subjects. Patients with type I gastric NENs <1 cm as well as those with non-ampullary duodenal NENs <1 cm with no associated syndrome can be safely managed by endoscopic resection. On the other hand, an active surveillance approach is preferred over surgery for patients with asymptomatic, non-functioning pancreatic NENs ≤2 cm without dilation of the main pancreatic duct or bile duct. As far as NENs of the appendix are concerned, appendectomy should be considered as curative when a R0 resection has been achieved in the presence of a tumor ≤1.5 cm, graded as G1 and without lymphovascular invasion. Finally, G1 rectal NENs ≤1 cm without invasion of the muscular layer can be safely treated by endoscopic resection. Therefore, surgeons should be aware of the existence of indolent GEP-NENs, in order to avoid unnecessary operations with associated postoperative complications.

Insights into Effects/Risks of Chronic Hypergastrinemia and Lifelong PPI Treatment in Man Based on Studies of Patients with Zollinger-Ellison Syndrome

The use of proton pump inhibitors (PPIs) over the last 30 years has rapidly increased both in the United States and worldwide. PPIs are not only very widely used both for approved indications (peptic ulcer disease, gastroesophageal reflux disease (GERD), Helicobacter pylori eradication regimens, stress ulcer prevention), but are also one of the most frequently off-label used drugs (25–70% of total). An increasing number of patients with moderate to advanced gastroesophageal reflux disease are remaining on PPI indefinitely. Whereas numerous studies show PPIs remain effective and safe, most of these studies are <5 years of duration and little data exist for >10 years of treatment. Recently, based primarily on observational/epidemiological studies, there have been an increasing number of reports raising issues about safety and side-effects with very long-term chronic treatment. Some of these safety issues are related to the possible long-term effects of chronic hypergastrinemia, which occurs in all patients taking chronic PPIs, others are related to the hypo-/achlorhydria that frequently occurs with chronic PPI treatment, and in others the mechanisms are unclear. These issues have raised considerable controversy in large part because of lack of long-term PPI treatment data (>10–20 years). Zollinger–Ellison syndrome (ZES) is caused by ectopic secretion of gastrin from a neuroendocrine tumor resulting in severe acid hypersecretion requiring life-long antisecretory treatment with PPIs, which are the drugs of choice. Because in <30% of patients with ZES, a long-term cure is not possible, these patients have life-long hypergastrinemia and require life-long treatment with PPIs. Therefore, ZES patients have been proposed as a good model of the long-term effects of hypergastrinemia in man as well as the effects/side-effects of very long-term PPI treatment. In this article, the insights from studies on ZES into these controversial issues with pertinence to chronic PPI use in non-ZES patients is reviewed, primarily concentrating on data from the prospective long-term studies of ZES patients at NIH.

Tumour type and size are prognostic factors in gastric neuroendocrine neoplasia: A multicentre retrospective study

BACKGROUND

Gastric neuroendocrine neoplasias (gNEN) are defined as type I if associated with atrophic body gastritis and type III when tumour is sporadic. This classification, together with grading and size, plays a crucial prognostic role. Nevertheless, the impact of these features on clinical outcome is not clear.

AIM

To identify factors predicting poor outcome.

PATIENTS AND METHODS

Analysis of type I and type III gNEN. A composite endpoint was defined if tumour-related death or metastases or angioinvasion were observed.

RESULTS

156 gNENs were evaluated: 137 (87.8%) type I and 19 (12.2%) type III. Among type I, 103 were G1 (75.2%) and 34 (24.8%) were G2. In type III group, 8 were G1 (42.1%), 10 were G2 (52.6%), and 1 was G3 (5.3%). Negative endpoint occurred in 18 patients including 10 type III and 8 type I. Male gender (p = 0.032), tumour type (p = 0.003) and size >10 mm (p = 0.024) were predictors for poor outcome, whereas Ki67 was not confirmed on multivariate analysis (p = 0.192). 5-yr survival rates in type I and type III were 100% and 76.2%, respectively (p = 0.0002).

CONCLUSIONS

Tumour size, tumour type and gender affect clinical outcome in gNENs. In contrast to NENs rising from other sites, Ki67 plays a less important role.

Multifocal G1-G2 gastric neuroendocrine tumors: Differentiating between Type I, II and III, a clinicopathologic review

Gastric neuroendocrine tumors (gNETs) are a rare entity that is increasing in incidence. Different pathophysiological processes can lead to the development of these tumors, appropriate histological analysis is necessary to differentiate between grade 1 (G1) and grade 2 (G2) tumors as this will impact the management of these patients based on their increased risk of lymph node and distant metastases. To provide a comprehensive clinicopathologic review of multifocal gastric neuroendocrine tumors, with particular emphasis on G1 and G2 tumors and differentiating between types I, II and II and risk stratification based upon immunohistochemical profile. This review is based on peer-reviewed literature and the authors’ experience. gNETs are a heterogenous group of tumors that is rising in incidence. These lesions while arise from the same cell type, they have different etiologies. Identifying the type of gNETs is a collective effort of clinical and pathologic correlation. The correct grading and staging of these lesions are of paramount significance, due its impact on patient management and prognosis.

Gastric neuroendocrine neoplasias: manifestations and comparative outcomes

Although gastric neuroendocrine neoplasias (gNEN) are an orphan disease, their incidence is rising. The heterogeneous clinical course powers the ongoing discussion of the most appropriate classification system and management. Prognostic relevance of proposed classifications was retrospectively analysed in 142 patients from a single tertiary referral centre. Baseline, management and survival data were acquired for statistical analyses. The distribution according to the clinicopathological typification was gNEN-1 (n = 86/60.6%), gNEN-2 (n = 7/4.9%), gNEN-3 (n = 24/16.9%) and gNEN-4 (n = 25/17.6%), while hypergastrinemia-associated gNEN-1 and -2 were all low-grade tumours (NET-G1/2), formerly termed sporadic gNEN-3 could be subdivided into gNEN-3 with grade 1 or 2 and gNEN-4 with grade 3 (NEC-G3). During follow-up 36 patients died (25%). The mean overall survival (OS) of all gNEN was 14.2 years. The OS differed statistically significant across all subgroups with either classification system. According to UICC 2017 TNM classification, OS differed for early and advanced stages, while WHO grading indicated poorer prognosis for NEC-G3. Cox regression analysis confirmed the independent prognostic validity of either classification system for survival. Particularly careful analysis of the clinical course of gNEN-1 (ECLomas, gastric carcinoids) confirmed their mostly benign, but recurrent and extremely slowly progressive behaviour with low risk of metastasis (7%) and an efficient long-term control by repetitive endoscopic procedures. Our study provides evidence for the validity of current classifications focusing on typing, grading and staging. These are crucial tools for risk stratification, especially to differentiate gNEN-1 as well as sporadic gNET and gNEC (gNEN-3 vs -4).

Management of Well-Differentiated High-Grade (G3) Neuroendocrine Tumors

OPINION STATEMENT

In 2017, the World Health Organization (WHO) classification for pancreatic NET was updated to include a new category of well-differentiated high-grade (Ki 67 > 20%) pancreatic tumors (NET G3), distinct from high-grade poorly differentiated neuroendocrine carcinoma (NEC). NET G3 are considered a molecularly, radiologically, and prognostically distinct entity compared to NEC and NET G1/G2. The optimal first-line management in NET G3 and sequencing therapies remains a challenge awaiting future trials taking into consideration the unique characteristics of this category. In this review, we aim to summarize the current evidence in the management of NET G3.

The Significant Influence of the Neuroendocrine Component on the Survival of Patients with Gastric Carcinoma Characterized by Coexisting Exocrine and Neuroendocrine Components

Background

Gastric adenocarcinoma patients with a neuroendocrine (NE) component are frequently observed in routine practice. Several previous studies have investigated the influence of a NE component on the survival of these patients; however, the results were inconsistent.

Methods

We retrospectively investigated a consecutive series of 95 gastric adenocarcinoma patients with a NE component and 190 gastric adenocarcinoma patients without a NE component. We adopted 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, and 90% as the cut-off proportions of the NE component, respectively, and analyzed the patients' overall survival according to the proportion of the NE component.

Results

The 1-, 3-, and 5-year actual survival rates of the patients with a NE component were 90.1%, 72.3%, and 67.2%, respectively, and for those without a NE component 94.2%, 79.3%, and 75.7%, respectively. The multivariate analysis showed that the patients with NE components >70% (HR: 2.156; 95% CI: 1.011, 4.597; p=0.047) and >90% (HR: 2.476; 95% CI: 1.088, 5.634; p=0.031) had significantly worse survival than those without a NE component. Only the diameter of tumors (>4.64 cm) (HR: 2.585; 95% CI: 1.112, 6.006; p=0.027) and pN3 (HR: 2.953; 95% CI: 1.051, 8.293; p=0.040) were independently associated with worse overall survival for gastric adenocarcinoma patients with a NE component (all p<0.05).

Conclusion

Gastric adenocarcinoma patients with a NE component >70% and >90% have significantly worse survival than those without a NE component. Only the diameter of tumors and the number of metastatic lymph nodes are independent prognostic factors for gastric adenocarcinoma patients with a NE component.

Efficacy and safety of ramucirumab-containing chemotherapy in patients with pretreated metastatic gastric neuroendocrine carcinoma

BACKGROUND

Ramucirumab (RAM), a monoclonal antibody for vascular endothelial growth factor 2 (VEGFR2), has been effective for advanced gastric adenocarcinoma (AC). However, little is known about the efficacy of RAM-containing chemotherapy (RAM-CTx) in gastric neuroendocrine carcinoma (G-NEC).

METHODS

We retrospectively analysed and compared the clinical outcomes of patients (pts) with G-NEC receiving RAM-CTx, G-NEC receiving CTx without RAM and AC receiving RAM-CTx in our hospital. G-NEC was defined by neuroendocrine carcinoma features, regardless of the proportion, based on histology and neuroendocrine markers (synaptophysin, chromogranin A or CD56). VEGFR2 expression in tumour vessels was evaluated in archival primary G-NEC tissues by immunohistochemistry using the same anti-VEGFR2 primary antibody and scoring scheme (vascular VEGFR2 H-score) as in the REGARD trial.

RESULTS

Seventeen G-NEC receiving RAM-CTx, 13 G-NEC receiving CTx without RAM and 173 AC pts receiving RAM-CTx were analysed. The overall response rate (59% vs 8 % vs 28%), progression-free survival (median 7.7 vs 1.8 vs 3.3 months) and overall survival (median 16.1 vs 8.6 vs 9.6 months) were significantly better in pts with G-NEC receiving RAM-CTx than G-NEC receiving CTx without RAM or AC receiving RAM-CTx. No severe or unexpected adverse events occurred. The median vascular VEGFR2 H-score, based on available G-NEC tissues from 12 pts receiving RAM-CTx, was 220 (range 150-260), which was markedly higher than that reported on AC tissues from the REGARD trial as historical control (median 35, range 0-240).

CONCLUSIONS

RAM-CTx showed a promising activity without severe or unexpected safety profile in pts with G-NEC. This may in part be explained by higher vascular VEGFR2 expression in G-NEC tissues.

Analysis of Gastric Carcinoma With Neuroendocrine Character

The clinical significance of gastric adenocarcinoma with neuroendocrine differentiation is unclear because of its rarity. The aim of this study was to suggest a treatment strategy for this tumor. A total of 10 resected gastric tumors with neuroendocrine character, including 3 neuroendocrine carcinomas (NECs) and 7 adenocarcinomas with neuroendocrine differentiation, were retrospectively reviewed regarding tumor characteristics and therapeutic outcomes. The gastric adenocarcinomas with neuroendocrine differentiation had high rates of lymph node metastasis and vessel invasion, and showed the poor prognoses as NEC. The median survival time (MST) was 13 months. Preoperative and postoperative chemotherapy tended to prolong the MST compared with operation alone (112.5 versus 5 months; P = 0.058). Moreover, chemotherapy for postoperative recurrence significantly contributed to improving prognosis (MST, 15 versus 7 months; P = 0.025). Gastric adenocarcinoma with neuroendocrine differentiation had equivalently high potential malignancy as NEC. More aggressive treatment should be considered for this tumor according to NEC.

Gastric Carcinoids

Gastric carcinoids, formally named gastric neuroendocrine neoplasms (NENs), are derived from enterochromaffin-like cells of the stomach and are increasingly diagnosed. A majority are designated as type I (related to autoimmune gastritis) and type II (related to gastrinoma) neoplasms that develop secondary to gastrin hypersecretion. Types I and II gastric carcinoids are mostly small-sized (1-2 cm), multiple, low-malignancy potential lesions mainly confined to the gastric mucosa/submucosa. These lesions have an indolent course and low metastatic potential. In contrast, type III gastric carcinoids are single, larger-sized (>2 cm), non-gastrin-related lesions that infiltrate the muscular layers associated with local and distant metastases.

Clinicopathological features and outcome of type 3 gastric neuroendocrine tumours

BACKGROUND

With the widespread use of endoscopy, small and low-grade type 3 gastric neuroendocrine tumours (NETs) are increasingly being detected. The clinicopathological features, biological behaviour and appropriate treatment strategy for these NETs remain unclear.

METHODS

Patients with biopsy-proven gastric NET and a normal fasting serum gastrin level were identified from a prospectively maintained database. Clinicopathological features and long-term outcome of local resection for type 3 NETs were reviewed retrospectively and compared according to tumour grade.

RESULTS

Some 32 patients with type 3 gastric NETs were included (25 patients with NET grade G1, 5 with G2 and 2 with G3). Pathological tumour size was 2·0 cm or less in 30 patients. All tumours were well differentiated, even G3 lesions, and all tumours but one were confined to the submucosal layer. G1 NETs were significantly smaller and had a significantly lower lymphovascular invasion rate than G2 and G3 NETs. Twenty-two patients with a G1 NET without lymphovascular invasion were treated with wedge or endoscopic resection. After a median follow-up of 59 (range 6-102) months, no patient with a G1 NET of 1·5 cm or smaller developed recurrence and one patient with a G1 NET larger than 1·5 cm had recurrence in a perigastric lymph node. Among seven patients with a G2 or G3 NET, two had lymph node metastasis and one had liver metastases.

CONCLUSION

Low-grade type 3 gastric NET has non-aggressive features and a favourable prognosis. Wedge or endoscopic resection may be a valid option for patients with type 3 gastric G1 NET no larger than 1·5 cm without lymphovascular invasion.

How should incidental NEN of the pancreas and gastrointestinal tract be followed?

Neuroendocrine gastro-entero-pancreatic neoplasms (GEP-NENs) constitute a heterogeneous group of tumors, whose incidence has increased over the years. The most frequent site for primary disease is the stomach followed by small and large intestine, and pancreas. In the last decade, a dramatic growing in the incidence of small, incidental GEP-NENs has been recorded. In parallel, an increasing attitude toward more conservative approaches instead of surgical management has being widely spreading. This is particularly true for small, asymptomatic, pancreatic NEN as for these tumor forms an active surveillance has proven to be safe and feasible. Primary site and biological features of the neoplasms lead to different strategies and indications for surveillance and follow-up. This review focuses on the current evidence on modality and timing of surveillance and conservative treatment of incidentally discovered lesions.

Not only stem cells, but also mature cells, particularly neuroendocrine cells, may develop into tumours: time for a paradigm shift

Stem cells are considered the origin of neoplasms in general, and malignant tumours in particular, and the stage at which the stem cells stop their differentiation determines the degree of malignancy. However, there is increasing evidence supporting an alternative paradigm. Tumours may develop by dedifferentiation from mature cells able to proliferate. Studies of gastric carcinogenesis demonstrate that mature neuroendocrine (NE) cells upon long-term overstimulation may develop through stages of hyperplasia, dysplasia, and rather benign tumours, into highly malignant carcinomas. Dedifferentiation of cells may change the histological appearance and impede the identification of the cellular origin, as seen with gastric carcinomas, which in many cases are dedifferentiated neuroendocrine tumours. Finding the cell of origin is important to identify risk factors for cancer, prevent tumour development, and tailor treatment. In the present review, we focus not only on gastric tumours, but also evaluate the role of neuroendocrine cells in tumourigenesis in two other foregut-derived organs, the lungs and the pancreas, as well as in the midgut-derived small intestine.

Prognostic Evaluations Tailored to Specific Gastric Neuroendocrine Neoplasms: Analysis Of 200 Cases with Extended Follow-Up

BACKGROUND

Gastric neuroendocrine neoplasms (NENs) are very heterogeneous, ranging from mostly indolent, atrophic gastritis-associated, type I neuroendocrine tumors (NETs), through highly malignant, poorly differentiated neuroendocrine carcinomas (pdNECs), to sporadic type III NETs with intermediate prognosis, and various rare tumor types. Histologic differentiation, proliferative grade, size, level of gastric wall invasion, and local or distant metastases are used as prognostic markers. However, their value remains to be tailored to specific gastric NENs.

METHODS

Series of type I NETs (n = 123 cases), type III NETs (n = 34 cases), and pdNECs (n = 43 cases) were retrospectively collected from four pathology centers specializing in endocrine pathology. All cases were characterized clinically and histopathologically. During follow-up (median 93 months) data were recorded to assess disease-specific patient survival.

RESULTS

Type I NETs, type III NETs, and pdNECs differed markedly in terms of tumor size, grade, invasive and metastatic power, as well as patient outcome. Size was used to stratify type I NETs into subgroups with significantly different invasive and metastatic behavior. All 70 type I NETs < 0.5 cm (micro-NETs) were uneventful. Ki67-based grading proved efficient for the prognostic stratification of type III NETs; however, grade 2 (G2) was not associated with tumor behavior in type I NETs. Although G3 NETs (2 type I and 9 type III) had a very poor prognosis, it was found that patient survival was longer with type III G3 NETs compared to pdNECs.

CONCLUSIONS

Given the marked, tumor type-related behavior differences, evaluation of gastric NEN prognostic parameters should be tailored to the type of neoplastic disease.

Ki67 labeling index: assessment and prognostic role in gastroenteropancreatic neuroendocrine neoplasms

In 1983, a monoclonal antibody, Ki67, was generated, that labeled the nuclei of proliferating non-neoplastic and neoplastic cells. The name Ki67 derived from the city of Kiel (Ki) where the antibody was produced in the university department of pathology and refers to the number of the original clone (67). Systematic assessment of the proliferative activity of tumors using Ki67 started in the 1990s, when Ki67, which only worked on frozen tissue, was complemented by the antibody MIB-1 that also worked in formalin-fixed tissues. Pancreatic neuroendocrine neoplasms (PanNENs) were the first endocrine tumors whose proliferative activity was assessed with Ki67. This approach was so successful that Ki67 was included as prognostic marker in the 2000 and 2004 WHO classifications of gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs). In 2010, the WHO classification of GEP-NENs introduced a three-tiered grading, originally proposed by ENETS in 2006 that was mainly based on the Ki67 index. As it has subsequently been shown that the Ki67 index is the most reliable factor in the prognostic evaluation of GEP-NENs, especially of PanNENs, the 2017 WHO classification of PanNENs requires its use and strongly recommends exact assessment of the proportion Ki67-labeled cells as basis for the calculation of the Ki67 index. Problems in assessing the Ki67 index include intertumoral and intratumoral staining heterogeneity and counting methods. Despite such problems, the Ki67 index has emerged as indispensable for the prognostic and therapeutic stratification of the majority of GEP-NENs and can barely be replaced by counting mitoses. In future, however, it can be anticipated that the Ki67 cut-offs experience refinement in relation to the type of tumor, its location, and its response to therapy. It is also possible that the prognostic risk of an individual tumor is calculated for each Ki67 unit and not for an "a priori" fixed Ki67 class.

Can the Ki-67 Labeling Index in Biopsy Specimens Predict the World Health Organization Grade of Rectal Neuroendocrine Tumors?

BACKGROUND

Being grade 2 is a known risk factor for metastasis in rectal neuroendocrine tumors (R-NETs). We aimed to identify the efficacy of the Ki-67 labeling index (LI) in endoscopic biopsy specimens to predict the World Health Organization (WHO) grade of R-NETs.

METHODS

A total of 59 patients with 60 R-NETs (43 WHO grade 1 and 17 WHO grade 2), treated between October 2002 and December 2014, were retrospectively evaluated. The patients included in the study underwent biopsies followed by endoscopic submucosal resection with a ligation device, trans-anal full-thickness surgical resection, or radical surgery with lymph node dissection. The Ki-67 LI in the biopsy and resected specimens were compared between the 2 tumor grade groups, and the diagnostic sensitivity, specificity, and positive and negative predictive values for the detection of WHO grade 2 tumors were evaluated.

RESULTS

The sensitivity, specificity, and positive and negative predictive values of the Ki-67 LI in biopsy specimens for predicting grade 2 tumors were 53% (9 of 17), 95% (41 of 43), 100% (9 of 9), and 87% (41 of 47), respectively. Pearson's rank correlation coefficient between the Ki-67 LI in the biopsy and resected specimens was 0.92.

CONCLUSIONS

The Ki-67 LI of the biopsy specimen is useful for determining the appropriate treatment for R-NETs.

Medical Therapy of Gastrointestinal Neuroendocrine Tumors

Intestinal neuroendocrine tumors (NETs) constitute a heterogeneous group with duodenal, small intestinal, colonic and rectal NETs. They constitute more than half of all NETs, with the highest frequencies in the rectum, small intestine, and colon. The tumor biology varies with the location of the primary tumor as well as with the grade and staging of the tumor. Small intestinal NETs usually present low proliferation and are treated in the first line with somatostatin analogs according to current guidelines. If progression occurs, one can add interferon alpha or change the treatment to everolimus. Peptide receptor radionuclide therapy (PRRT) with Lutetium¹⁷⁷-DOTATATE can be an option in the future after registration of the compound. Rectal tumors are usually small when they metastasize; they can be treated with somatostatin analogs but more so with PRRT, while another option is of course everolimus. Colonic NETs are more aggressive than the rest of intestinal NETs and will be treated with everolimus, sometimes in combination with somatostatin analogs based on positive scintigraphy. Another option is a cytotoxic agent such as streptozotocin plus 5-fluorouracil (5-FU) or temozolomide plus capecitabine. The most aggressive tumors, i.e. neuroendocrine carcinoma G3, are treated with a platin-based therapy plus etoposide; if they present with a lower proliferation, i.e. <50%, temozolomide plus capecitabine plus bevacizumab can also be attempted. Duodenal NETs are mostly treated similar to pancreatic NETs, either with cytotoxic agents, streptozotocin plus 5-FU, or temozolomide plus capecitabine, or with targeted agents such as everolimus.

Management of gastric neuro-endocrine tumours in a large French national cohort (GTE)

INTRODUCTION

Gastric neuro-endocrine tumours are rare. European guidelines for the management of neuro-endocrine tumours have been published in 2012. The aim of our survey was to study the management of gastric neuro-endocrine tumours registered in the national cohort. A prospective national cohort registers the Neuro-endocrine tumours in France since January 2003 (GTE network). We reviewed all the individual medical reports of gastric neuro-endocrine tumours in order to collect data on treatment.

RESULTS

One hundred and ninety seven gastric neuro-endocrine tumours diagnosed between 1964 and 2013 in 20 centres were registered. For 181 cases data were considered complete for our survey. Eighty four tumours were type 1 (46.4%); five types 2 (2.8%); 52 types 3 (28.7%) and 40 types 4 (22.1%). Types 1 and 2 were first endoscopically managed in 93 and 60% of cases, respectively, whereas surgery was first done in 45 and 42%, respectively, of types 3 and 4. Systemic treatment, chemotherapy and/or somatostatin analogue, was first administered exclusively for types 3 and 4. Near 3% of types 1 and 40% of types 2 received at a time somatostatin analogue treatment. Five-year survival rates were 98.3, 100, 63.2 and 31.8% for types 1, 2, 3 and 4, respectively.

CONCLUSION

The great majority of gastric neuro-endocrine tumours registered in this national cohort are treated in accordance with the current guidelines. The survival rates we reported must be interpreted with caution, because this cohort registered preferentially selected patients eligible for treatment. The registration of all the gastric neuro-endocrine tumours, in particular type 1 considered as benign and type 4 not eligible for specific anti-cancer treatment must be encouraged.

Risk factors of type 1 gastric neuroendocrine neoplasia in patients with chronic atrophic gastritis. A retrospective, multicentre study

The aim of this retrospective study was to evaluate the presence of risk factors for a type 1 gastric neuroendocrine neoplasia in a large cohort of patients with chronic atrophic gastritis. The study design consisted of an Italian multicentre, retrospective analysis. The study included all consecutive patients with chronic atrophic gastritis with or without type 1 gastric neuroendocrine neoplasias followed at the participating centres. Two hundred and twenty-nine patients with chronic atrophic gastritis were enroled at the participating centres. A total of 207 patients (154 female, 53 males, median age: 56.0 years) were included in the final analysis. One hundred and twenty-six patients had chronic atrophic gastritis without a gastric neuroendocrine neoplasia and 81 had a chronic atrophic gastritis with type 1 gastric neuroendocrine neoplasia. The median Chromogranin A level, evaluated in 141 patients, was 52.0 U/L. At upper gastrointestinal endoscopy, atrophy of the gastric mucosa was mild/moderate in 137 patients and severe in 68. Intestinal metaplasia of the corpus was present in 168 patients. At histological examination, 81 patients had a gastric neuroendocrine neoplasia (42 patients had a NET G1 and 33 a NET G2). The median Ki67 index was 2.0 %. At univariate and multivariate analysis, the risk factors for a gastric neuroendocrine neoplasia were: male gender, chromogranin A greater than 61 U/L, presence of intestinal metaplasia and age equal to or greater than 59 years. Chromogranin A greater than 61 U/L, the presence of intestinal metaplasia and male gender were independent risk factors for a type 1 gastric neuroendocrine neoplasia in patients with chronic atrophic gastritis.

Comparison of relapse-free survival in gastric neuroendocrine carcinoma (WHO grade 3) and gastric carcinoma

BACKGROUND

We compared relapse-free survival (RFS) in gastric neuroendocrine carcinoma (WHO grade 3) and gastric carcinoma (GC). This is one of very few studies that compare the prognosis of poorly differentiated neuroendocrine carcinoma (WHO grade 3, G3 NEC) with that of GC.

METHODS

Between 1996 and 2014, 63 patients were diagnosed with G3 NEC of the stomach and 56 with gastric neuroendocrine tumors (NETs) with GC at Asan Medical Center in Seoul, Korea. We also randomly selected 762 patients diagnosed with GC between 1999 and 2008.

RESULTS

Patients with G3 NEC tumors that invaded the muscularis propria or shallower had poorer RFS than those with GC of the same type, while G3 NEC that invaded the subserosa or deeper had similar RFS to GC of that type. Patients diagnosed with G3 NEC with N0 or N2 had poorer RFS than the corresponding patients with GC, while those who had G3 NEC with N1 or N3 had similar RFS to the corresponding patients with GC. G3 NEC patients had poorer RFS than well-differentiated, moderately differentiated and poorly differentiated GC patients, while G3 NEC patients had similar RFS to that of those with signet ring cell carcinoma (SRC). In addition, patients with G3 NEC of stages I or IIa had poorer RFS than those with corresponding GC, while G3 NEC stage IIb or greater had similar RFS to the corresponding GC.

CONCLUSIONS

Non-advanced G3 NEC showed poorer RFS than GC excluding SRC, while advanced G3 NEC has a similar RFS to that of GC without SRC. Therefore, we recommend that patients with non-advanced G3 NEC of the stomach be given a more aggressive treatment and surveillance than those with non-advanced GC excluding SRC.

[Neuroendocrine neoplasia of the stomach : What is new?]

INTRODUCTION

Neuroendocrine Neoplasms are classified according to the new WHO classification in (1.) well differentiated neuroendocrine tumors G1 (NET G1, Ki67 ≤ 2 or mitosis count <2) and (2.) well differentiated neuroendocrine tumors G2 (NET G2, Ki67 3-20 or mitosis count 2-20) and (3.) poorly differentiated neuroendocrine carcinomas G3 (NEC G3, Ki67 > 20 or mitosis count >20).

MATERIAL AND METHODS

In this study 310 NENs of the Ludwig-Maximilians-University in Munich were reevaluated according to the new WHO classification.

RESULTS

7% of the analyzed NENs were presented as neoplasias of the stomach. In NENs of the stomach three distinct subtypes are recognized: (1) type 1 associated with autoimmune chronic atrophic gastritis (2) type 2, associated with multiple endocrine neoplasia (MEN1) and Zollinger-Ellison Syndrom; and (3) type 3, sporadic tumors.

DISCUSSION

Precursor lesions (i. e. hyperplasia of the ECL cells) are found in patients with hypergastrinaemia (type 1 and 2). This article should provide insights into the diagnosis of NENs of the stomach with emphasis on the new international standard.

Clinicopathological significance of gastric poorly differentiated medullary carcinoma

Poorly differentiated gastric adenocarcinoma of solid type is known to show a clinicopathological diversity, but its morphological characteristics have rarely been investigated. In this study, we defined poorly differentiated medullary carcinoma indicating the following three characteristics: (i) more than 90% of the entire tumor were composed of poorly differentiated adenocarcinoma in a medullary growth, (ii) the tumor exhibited an expansive growth at the tumor margin, and (iii) special types such as an α-fetoprotein-producing carcinoma, neuroendocrine carcinoma, and carcinoma with lymphoid stroma were excluded. Based on the definition, we subclassified the poorly differentiated gastric adenocarcinoma of solid type into the two groups: medullary carcinoma and non-medullary carcinoma, and clinicopathologically analyzed 23 cases of medullary carcinomas and 38 cases of non-medullary carcinomas. The medullary carcinomas less frequently displayed lymphatic invasion, venous invasion, and lymph node metastasis, compared with the non-medullary carcinoma (P < 0.001, P = 0.002, and P < 0.001, respectively). The patients with medullary carcinomas significantly showed better disease-free survival (P = 0.017). This is the first study to demonstrate that poorly differentiated adenocarcinoma of solid type can be subclassified into tumors with low and high malignant potentials. Gastric poorly differentiated medullary carcinoma is considered to be a novel histological type predicting good patients' prognosis.

Insights into gastric neuroendocrine tumors burden

Type 1 gastric neuroendocrine tumors (gNETs) are usually small lesions, restricted to mucosal and sub-mucosal layers of corpus and fundus, with low aggressive behavior, for the majority of cases. Nevertheless, some cases present aggressive behavior. The increasing incidence of gNETs brings together a new relevant problem: how to identify potentially aggressive type 1 gNETs. The challenging problem seems to be finding out signs or features able to predict potentially aggressive cases, allowing a tailored approach, since the involved societies dedicated to provide guidelines for management of these neoplasms apparently failed in producing staging systems able to accurately predict prognosis of these tumors. Additionally, it is also important to try to find out explanations for increasing incidence, as well as to identify potential targets aiming to reach better control of this neoplasia. Here, we discuss potential pathways implicated in aggressive behavior, as well as new strategies to improve clinical management of these tumors.

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

BACKGROUND

Several types of neuroendocrine neoplasms (NENs) have been described in the duodenal tract, from low-grade tumors (NETs) to high-grade neuroendocrine carcinomas (NECs). A comprehensive analysis of histology, hormonal profile and prognostic parameters of a sufficiently large duodenal NEN series to cover all main kinds of neoplasms is however lacking.

METHODS

We collected a retrospective series of 203 duodenal wall and ampullary region NENs, from six specialized endocrine pathology centers. All were characterized histopathologically and histochemically, and 190 were followed for a median of 9 years.

RESULTS

Twenty-seven poorly differentiated NECs, mostly from the ampullary region, were identified and shown to lead to patient demise in a median of 10 months. Among 176 NETs, four subtypes were characterized, including 20 gastrinomas, 37 ampullary-type somatostatin-producing NETs (ASTs), 12 gangliocytic paragangliomas (GPs) and 106 nonfunctioning NETs (nfNETs). ASTs and GPs were mostly localized in the ampullary/periampullary region, while gastrinomas and nfNETs were mainly from the proximal duodenum. ASTs and gastrinomas showed high rates of local infiltration (especially lymphoinvasion and deep duodenal wall/pancreatic tissue invasion) and lymph node metastasis, while nfNETs had significantly lower and more size-dependent local invasive potential. Disease-specific survival differed significantly between NETs and NECs, though not among NET subtypes. NET cases with distant metastases (n = 23) were significantly associated with larger size, higher proliferative grade, lymphovascular invasion, deep invasion and local lymph node metastasis.

CONCLUSION

Our careful analysis of a large series of duodenal NENs identified five histologically and prognostically different histotypes of potential clinical relevance.

Histological characterisation and prognostic evaluation of 62 gastric neuroendocrine carcinomas

AIM OF THE STUDY

To determine the significance of expression of synaptophysin, chromogranin A, and Ki-67 and their association with clinicopathological parameters, and to find out the possible prognostic factors in gastric neuroendocrine carcinoma (G-NEC).

MATERIAL AND METHODS

We investigated the immunohistochemical features and prognosis of 62 G-NECs, and evaluated the association among expressions of synaptophysin, chromogranin A, and Ki-67, clinicopathological variables, and outcome.

RESULTS

Chromogranin A expression was found more commonly in small-cell NECs (9/9, 100%) than in large-cell NECs (27/53, 51%) (p = 0.008). No statistical significance was found in Ki-67 (p = 0.494) or synaptophysin (p > 0.1) expression between NEC cell types. Correlation analyses revealed that Ki-67 expression was significantly associated with mid-third disease of stomach (p = 0.005) and vascular involvement (p = 0.006), and had a trend of significant correlation with tumour relapse (p = 0.078). High expression of chromogranin A was significantly associated with histology of small-cell NECs (p = 0.008) and lesser tumour greatest dimension (p = 0.038). The prognostic significance was determined by means of Kaplan-Meier survival estimates and log-rank tests, and as a result, early TNM staging and postoperative chemotherapy were found to be correlated with longer overall survival (p < 0.05). Univariate analysis revealed associations between poor prognosis in NECs and several factors, including high TNM staging (p = 0.048), vascular involvement (p = 0.023), relapse (p = 0.004), and microscopic/macroscopic residual tumour (R1/2, p < 0.001). In a multivariate analysis, relapse was identified as the sole independent prognostic factor.

CONCLUSIONS

No significant correlation between survival and expression of synaptophysin, chromogranin A, or Ki-67 has been determined in G-NECs. Our study indicated that early diagnosis, no-residual-tumour resection, and postoperative chemotherapy were possible prognostic factors.

Sporadic Gastric Well-Differentiated Neuroendocrine Tumors Have a Higher Ki-67 Proliferative Index

Well-differentiated neuroendocrine tumor (WDNET) of the stomach can arise in three distinct clinical settings: (1) in association with autoimmune atrophic gastritis, (2) in association with multiple neuroendocrine neoplasia type I (MEN I) or Zollinger-Ellison syndrome (ZES), or (3) sporadic. The Ki-67 proliferative index (PI) in gastric WDNETs in these three distinct clinical settings has not been evaluated in detail. Forty-five gastric WNETs underwent polypectomy (n = 4), endoscopic mucosal resection (n = 12), and surgical resection (n = 29) between 1994 and 2015 were included. H&E slides from each case were reviewed, and Ki-67 immunostain was performed on one representative tumor block. Ki-67 PI was determined by quantitative Aperio image analysis software in areas of strongest nuclear labeling ("hot spots"), and correlated with underlying clinical and pathological features. Twenty-one patients were male and 24 female with a median age of 57 years (range, 30-80 years). Tumors were classified as type I (n = 17), type II (n = 6), and type III (n = 22) WDNETs. Types II and III showed more advanced TNM stage compared to type I (p = 0.02, overall). WHO grade based on Ki-67 PI was higher in type III WDNETs [grade 1 (G1), n = 3; grade 2 (G2), n = 15; and grade 3 (G3), n = 4] than in type I WDNETs [G1, n = 5; G2, n = 12] and in type II WDNETs [G1, n = 2; G2, n = 4] (p = 0.050, overall). Ki-67 PI was significantly higher in type III WDNETs (mean ± SD = 13.0 ± 13.3 %) than in non-sporadic (type I and II) WDNETs (mean ± SD = 5.3 ± 3.3 %; p = 0.015). There was no difference in Ki-67 PI between type I WDNETs (mean ± SD = 5.2 ± 3.5 %) and type II WDNETs (mean ± SD = 5.6 ± 3.1%; p = 0.817). Higher Ki-67 PI was associated with higher tumor T stage (p = 0.003) and also tended to be associated with lymph node metastasis (p = 0.071). In the Kaplan-Meier survival analysis, type I was associated with a significantly longer disease-free survival (DFS) time compared to type II (p = 0.018) or III (0.010). Also, the WHO G3 group had a significantly shorter DFS time than the WHO G1 (p = 0.020) or G2 (p = 0.007) group. Gastric WDNET is a heterogeneous disease entity encompassing three clinical subtypes-type I, type II, and type III-having their own distinct clinicopathologic characteristics and prognosis. Our results showed that sporadic (type III) WDNET had a significantly higher Ki-67 PI than non-sporadic cases (type I or II); increased PI was associated with higher tumor stage. We also described four type III cases of morphologically WD gastric NET with WHO grade 3 on the basis of Ki-67 PI.

Evaluation of clinicopathological factors related to the prognosis of gastric neuroendocrine carcinoma

BACKGROUND

Research on the clinicopathology and prognosis of gastric neuroendocrine carcinoma (GNEC) is rare, and a uniform standard for treatment has not been established. Therefore, we retrospectively analyzed the clinical data of 132 cases of GNEC to investigate the factors influencing prognosis.

METHODS

A total of 132 patients diagnosed with GNEC at Fujian Medical University Union Hospital from January 2006 to December 2013 were enrolled. This study was performed to analyze the factors related to patient prognosis.

RESULTS

In total, 58 men and 74 women whose ages ranged from 38 to 83 years old (62 ± 10) were enrolled. The 1- and 3-year survival rates for these patients were 83.9% and 47.6%, respectively. Of these patients, 100 underwent radical resection, 22 underwent palliative resection, and 10 received chemotherapy alone. The median survival times following radical resection, palliative resection and chemotherapy alone were 48, 20 and 12 months, respectively (P < 0.01). Univariate and multivariate survival analyses of patients who underwent radical resection showed that tumor size, N stage, Ki-67 labeling index, mitotic index and the application of postoperative adjuvant chemotherapy were independent factors affecting patient prognosis. The correlation analysis of the Ki-67 labeling index and mitotic index with prognosis showed that patient survival decreased significantly when the Ki-67 labeling index increased (P < 0.05).

CONCLUSIONS

Patients who underwent radical resection had the best prognosis among GNEC. For these patients, tumor size, N stage, Ki-67 labeling index, mitotic index and the application of postoperative adjuvant chemotherapy were the clinicopathological factors significantly associated with patient prognosis.

Gastroenteropancreatic Well-Differentiated Grade 3 Neuroendocrine Tumors: Review and Position Statement

: In 2010, the World Health Organization (WHO) classification of neuroendocrine neoplasms was reviewed and validated the crucial role of the proliferative rate. According to the WHO classification 2010, gastroenteropancreatic neuroendocrine neoplasms are classified as well-differentiated neuroendocrine tumors (NETs) of grade 1 or 2 in up to 84%, or poorly differentiated neuroendocrine carcinomas in 6%-8%. Neuroendocrine carcinomas are of grade G. Recently, a proportion of neuroendocrine tumors presenting a number of mitoses or a Ki-67 index higher than 20% and a well-differentiated morphology have been identified, calling for a new category, well-differentiated grade 3 NET (NET G-3). Studies that have reported the characteristics of neuroendocrine neoplasms have identified more well-differentiated NET G-3 than neuroendocrine carcinomas. The main localizations of NET G-3 are the pancreas, stomach, and colon. Treatment for NET G-3 is not standardized and is balanced between G-1/2 neuroendocrine tumor and neuroendocrine carcinoma treatments. In nonmetastatic neuroendocrine tumors, the European and American guidelines recommended a surgical resection for localized neuroendocrine neoplasm, irrespective of the tumor grading. In NET G-3, chemotherapy is the benchmark if the main treatment goal is reduction of the tumor mass, particularly if it would allow a secondary surgery. In the present work, we review the epidemiology and make recommendations for the management of NET G-3.

IMPLICATIONS FOR PRACTICE

Neuroendocrine tumors presenting a number of mitoses or a Ki-67 index higher than 20% and a well-differentiated morphology have been identified and named well-differentiated grade 3 neuroendocrine tumors (NET G-3). The main localizations of NET G-3 are the pancreas, stomach, and colon. The prognosis is worse than that for NET G-2. In nonmetastatic NET G-3, surgery appeared to be the first option. The chemotherapy regimen in pancreatic NET G-3 should be in line with that implemented in NET G-1/2 when the Ki-67 index is below 55% and should be in line with that implemented for neuroendocrine carcinoma when Ki-67 is above 55%.

Does long-term profound inhibition of gastric acid secretion increase the risk of ECL cell-derived tumors in man?

OBJECTIVE

Since the description of ECL cell-derived tumors in rodents after long-term profound acid inhibition inducing hypergastrinemia, there has been concern that proton pump inhibitors (PPIs) could also do that in man. The recent description of a Spanish family with gastric ECL cell tumors at the age of about 30 years secondary to a defect in the proton pump due to mutation in the ATP4A gene clearly shows that hypergastrinemia alone also is sufficient to induce ECL cell neoplasia in man. The present review aims to evaluate the risk of gastric neoplasia secondary to gastric acid inhibition.

METHODS

Literature (MEDLINE) was searched for the role of the ECL cell in gastric carcinogenesis in animals and man in general and particularly secondary to long-term inhibition of acid secretion.

RESULTS

An important proportion of patients treated with PPI develops hypergastrinemia causing ECL cell hyperplasia and the first descriptions of ECL cell carcinoids secondary to PPI have been reported. The role of the ECL cell has hitherto been under estimated in gastric carcinogenesis in man where for instance the signet ring cell type of gastric carcinoma seems to originate from the ECL cell.

CONCLUSIONS

The first two of three steps in rodent ECL cell carcinogenesis (hyperplasia, carcinoid, and carcinoma) secondary to PPI dosing, have been described for man. It is every reason to believe that the final step, gastric carcinoma, will develop also in man. Clinical decisions should be based not only on so-called evidence based medicine, but also on physiological knowledge and animal studies.