Current concepts in the diagnosis and management of type 1 gastric neuroendocrine neoplasms

When rare diseases crisscross within the same patient: von Hippel-Lindau and type 1 gastric neuroendocrine tumor

Von-Hippel-Lindau (VHL) is a genetic multisystem disorder characterized by visceral cysts and benign and malignant tumors in various organs. Herein, we present the case of a 23-year-old woman with VHL presenting with multiple gastric neuroendocrine neoplasms (gNENs) type 1 in the context of chronic autoimmune gastritis (CAG). Although gNENs are not acknowledged as a typical entity in VHL patients, in the present case, gNENs were composed of neoplastic cells with clear cytoplasm usually seen in tumors related to VHL disease. We additionally performed a literature review on the presence of neuroendocrine clear cell tumors and report on further cases of clear cell NENs. The present case illustrates that clear-cell transformation in gNENs may be due to the dual genetic background of the patient; the real oncogenic stimulus may be more closely related to CAG than to VHL disease accompanied by an interplay between neoplastic and autoimmune processes. Therefore, close monitoring of patients with clear cell NENs appears to be important before excluding VHL disease, even in the context of phenotypically unrelated diseases.

Clinical experience sharing on gastric microneuroendocrine tumors: A case report

BACKGROUND

The majority of gastric neuroendocrine tumors (G-NENs) are present in various lesions under endoscopy, and they can be polypoid uplifts, submucosal tumors or papules, erosions, and ulcers. The lesions are mostly confined to the mucosal or submucosal layer, usually less than 2 cm, and exclusively localized to the gastric body or fundus. In type 1 G-NENs, about 22% of cases have no visible lesions under an endoscope, and such lesions can only be detected via biopsies (microcarcinoids).

CASE SUMMARY

A 67-year-old female patient with appetite loss for more than half a year and personal history of hyperthyroidism was admitted to our hospital. After admission, a random multi-point biopsy was performed on the gastric body, fundus, angle, and antrum through gastroscopy. Pathological examination showed chronic severe atrophic gastritis in the fundus and body of the stomach. The small curvature of the gastric body, the anterior wall of the gastric body, and the posterior wall of the gastric body displayed proliferation of intestinal chromaffin cells. The curvature of the gastric body showed neuroendocrine tumor G1 (carcinoid), while the antrum and angle of the stomach showed mild atrophic gastritis with mild intestinal metaplasia. Immunohistochemical examination showed that the greater curvature of the gastric body was Syn (+), CgA (+), and Ki-67 (+, approximately 1%), which is consistent with neuroendocrine tumors (grade 1). Regular gastroscopy and biopsy should be performed every one to two years to monitor G-NENs.

CONCLUSION

In the case under study, the patient did not have any visible raised lesions under a gastroscope, and the lesions were found only after a random biopsy. This article combines the endoscopic manifestations and clinical features of the lesions in this case to improve the diagnosis of G-NENs.

Factors Predicting Type I Gastric Neuroendocrine Neoplasia Recurrence: A Single-Center Study

Type I gastric neuroendocrine neoplasms (gNENs) are associated with atrophic gastritis and have a high recurrence rate, which means frequent endoscopies are required. The objective of this study was to identify factors predicting the local recurrence of type I gNENs. The clinical course and the pathological and biochemical data of patients with type I gNENs treated at Bnai Zion Medical Center between 2006 and 2022 were analyzed retrospectively. Twenty-seven type I gNENs were evaluated. The follow-up period was 41 months (range: 11–288 months). Recurrence of the tumor occurred in 13/27 (48%) patients after 35 months (median (M), interquartile range (IQR): 21–67.5). Serum gastrin levels were significantly higher in patients with recurrent disease versus patients with non-recurrent disease (788 vs. 394 ng/L; p = 0.047), while the Ki-67 index was significantly lower in patients with recurrent disease versus patients with non-recurrent disease (1% vs. 3.5%; p = 0.035). Tumor size, mitotic count, and serum chromogranin A levels did not correlate with recurrence. The present study emphasizes the role of gastrin in the pathogenesis of gNEN recurrence and highlights the debate regarding the ability of the Ki-67 index to predict the clinical course of this disease.

Incidence of Gastric Neoplasms Arising from Autoimmune Metaplastic Atrophic Gastritis: A Systematic Review and Case Reports

Autoimmune metaplastic atrophic gastritis (AMAG) is associated with an increased risk of gastric neoplasms. This study aimed to systematically analyze the incidence rate of gastric cancer (GC), low-grade dysplasia (LGD) and type-1 gastric neuroendocrine tumor (gNETs) development in AMAG adults. Studies on AMAG patients reporting the incidence of gastric neoplasms was identified through a systematic search in PUBMED and EMBASE. Study quality was assessed using the Joanna Briggs Institute quality assessment tool. Incidence rates of GC, LGD and type-1 gNETs were examined by meta-analysis. Thirteen studies met eligibility criteria. Incidence rate of gastric cancer calculated from the pooled data was 0.14% per person-year in both single-center studies and national registration studies. Meta-analysis showed a relative risk of 11.05 (95% CI: 6.39-19.11) for gastric cancer development in AMAG patients. The calculated pooled gastric LGD and type-1 gNETs incidence rates were 0.52% and 0.83% per person-year, respectively. As for experience from our center, we presented three distinctive cases of gastric neoplasm arising from the background of AMAG. This study underscores the potential for malignant transformation of precancerous lesions and reiterates the importance of careful esophagogastroduodenoscopy screening.

[Difficulties in diagnosis of neuroendocrine tumors of the gastrointestinal tract]

We present diagnosis and complex minimally invasive surgical treatment of a patient with long-standing neuroendocrine tumor of the upper gastrointestinal tract. We followed-up a 50-year-old female patient after endoscopic resection of polypoid neoplasm of the stomach for 2 non-organ retroperitoneal neoplasms in the area of hepatogastric ligament. After a comprehensive examination and minimally invasive surgery including laparoscopic resection of retroperitoneal neoplasms, immunohistochemical examination, PET-CT and targeted endoscopic ultrasound of the stomach, we diagnosed a highly differentiated gastric neuroendocrine tumor with metastases into lymph nodes of hepatogastric ligament. Combination of endoscopic and morphological diagnosis with rigorous histological examination of specimen provided correct diagnosis and reasonable strategy of aggressive minimally invasive surgical treatment.

An update on the diagnosis of gastroenteropancreatic neuroendocrine neoplasms

Gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) arise from neuroendocrine cells found throughout the gastrointestinal tract and islet cells of the pancreas. The incidence and prevalence of GEP-NENs have been increasing each year due to higher awareness, improved diagnostic modalities, and increased incidental detection on cross-sectional imaging and endoscopy for cancer screening and other conditions and symptoms. GEP-NENs are a heterogeneous group of tumors and have a wide range in clinical presentation, histopathologic features, and molecular biology. Clinical presentation most commonly depends on whether the GEP-NEN secretes an active hormone. The World Health Organization recently updated the classification of GEP-NENs to introduce a distinction between high-grade neuroendocrine tumors and neuroendocrine carcinomas, which can be identified using histology and molecular studies and are more aggressive with a worse prognosis compared to high-grade neuroendocrine tumors. As our understanding of the biology of GEP-NENs has grown, new and improved diagnostic modalities can be developed and optimized. Here, we discuss clinical features and updates in diagnosis, including histopathological analysis, biomarkers, molecular techniques, and radiology of GEP-NENs. We review established diagnostic tests and discuss promising novel diagnostic tests that are currently in development or require further investigation and validation prior to broad utilization in patient care.

Gastric Neuroendocrine Tumor Mimicking Gastrointestinal Stromal Tumor: A Case Report

Gastric neuroendocrine tumors (NETs) are rare lesions that arise from enterochromaffin-like cells of the gastric mucosa. Gastric NETs are classified into 3 types of NETs and poorly differentiated neuroendocrine cancers. Most gastric NETs usually present as hemispherical, yellowish, polypoid lesions with a central depression and often as subepithelial tumors (SETs) because they are confined within the submucosal layer. Here, we report a case of gastric NET presenting as SET mimicking a gastrointestinal stromal tumor (GIST). Endoscopy revealed a 2.3-cm-sized SET with intact surface mucosa, and endoscopic ultrasonography showed a homogeneous hypoechoic lesion with a well-circumscribed margin. Typical features of gastric NET, such as yellowish mucosal changes or central ulceration, were not observed. GIST was suspected, and a laparoscopic wedge resection was performed. The final diagnosis was gastric NET with grade 2 differentiation.

Type I Gastric Neuroendocrine Tumor Presenting as Acute Upper Gastrointestinal Bleed

Gastric neuroendocrine tumors (GNETs) are rare and subdivided into type I, type II, and type III. Types I and II are gastrin-dependent and are usually benign, whereas type III is gastrin-independent and more aggressive. Type I accounts for 70-80% of all GNETs. Most of them are asymptomatic and incidentally detected on endoscopy. It can sometimes present with iron and B12 deficiency, dyspepsia, and less commonly with an upper GI bleed. We present a case of type I GNET who came to the hospital with melena and esophagogastroduodenoscopy (EGD) showing a 3-cm bleeding polyp and histopathology revealing a well-differentiated neuroendocrine tumor with angioinvasion.

Molecular Pathology of Well-Differentiated Gastro-entero-pancreatic Neuroendocrine Tumors

Well differentiated neuroendocrine tumors (NETs) arising in the gastrointestinal and pancreaticobiliary system are the most common neuroendocrine neoplasms. Studies of the molecular basis of these lesions have identified genetic mutations that predispose to familial endocrine neoplasia syndromes and occur both as germline events and in sporadic tumors. The mutations often involve epigenetic regulators rather than the oncogenes and tumor suppressors that are affected in other malignancies. Somatic copy number alterations and miRNAs have also been implicated in the development and progression of some of these tumors. The molecular profiles differ by location, but many are shared by tumors in other sites, including those outside the gastroenteropancreatic system. The approach to therapy relies on both the neuroendocrine nature of these tumors and the identification of specific alterations that can serve as targets for precision oncologic approaches.

Response and relapse rates after treatment with long-acting somatostatin analogs in multifocal or recurrent type-1 gastric carcinoids: A systematic review and meta-analysis

BACKGROUND

Type-1 gastric neuroendocrine tumors represent a recurring disease and long-acting somatostatin analogs can inhibit both gastrin release and endocrine cell proliferation. The efficacy and timing of this treatment are still unclear. We performed a systematic review of the literature to clarify the role of somatostatin analog treatment in type-1 gastric neuroendocrine tumors.

METHODS

A computerized literature search was performed using relevant keywords to identify all the pertinent articles published in the last 15 years.

RESULTS

Eight studies were included in this systematic review on somatostatin analogs in type-1 gastric neuroendocrine tumors. A complete response rate ranged from 25-100%. When only the six prospective studies were considered, no significant heterogeneity was observed, and the pooled cumulative complete response rate was 84.5% (confidence interval 73.8-92.8). Three studies evaluated the type-1 gastric neuroendocrine tumor recurrence, with a cumulative relapse rate of 30.2% (confidence interval 13.1-50.6) after 34 months.

CONCLUSION

Somatostatin analogs, namely lanreotide and octreotide, have an excellent response rate, with a good safety profile in selected type-1 gastric neuroendocrine tumors, which cannot be safely managed by endoscopic follow-up or resection due to multiple or frequently recurring disease. After therapy discontinuation, the cumulative relapse rate observed after a median 34-month follow-up was relatively high (30.2%).

A SOX2 Reporter System Identifies Gastric Cancer Stem-Like Cells Sensitive to Monensin

Gastric cancer remains a serious health burden with few therapeutic options. Therefore, the recognition of cancer stem cells (CSCs) as seeds of the tumorigenic process makes them a prime therapeutic target. Knowing that the transcription factors SOX2 and OCT4 promote stemness, our approach was to isolate stem-like cells in human gastric cancer cell lines using a traceable reporter system based on SOX2/OCT4 activity (SORE6-GFP). Cells transduced with the SORE6-GFP reporter system were sorted into SORE6+ and SORE6- cell populations, and their biological behavior characterized. SORE6+ cells were enriched for SOX2 and exhibited CSC features, including a greater ability to proliferate and form gastrospheres in non-adherent conditions, a larger in vivo tumor initiating capability, and increased resistance to 5-fluorouracil (5-FU) treatment. The overexpression and knockdown of SOX2 revealed a crucial role of SOX2 in cell proliferation and drug resistance. By combining the reporter system with a high-throughput screening of pharmacologically active small molecules we identified monensin, an ionophore antibiotic, displaying selective toxicity to SORE6+ cells. The ability of SORE6-GFP reporter system to recognize cancer stem-like cells facilitates our understanding of gastric CSC biology and serves as a platform for the identification of powerful therapeutics for targeting gastric CSCs.

[Gastric neuroendocrine tumors]

Gastrointestinal neuroendocrine tumors are rare neoplasms. Currently, incidence of gastric neuroendocrine tumors (gNETs) is being significantly increased. There are 3 groups of gNETs: types I, II and III. Each type has important features regarding clinical picture, prognosis and treatment strategy. Type I is the most common (70-80%) and associated with chronic atrophic gastritis including autoimmune gastritis and Helicobacter associated atrophic gastritis. Type II (5-6%) is associated with multiple endocrine neoplasia type I and Zollinger-Ellison syndrome (MEN I - ZES). Both types are characterized by hypergastrinemia and small tumor dimension. These neoplasms are multiple and mostly benign. On the contrary, NETs type III (10-15%) is not associated with hypergastrinemia and represented by single large neoplasms. Tumors are malignant as a rule. Therefore, surgical resection and chemotherapy are preferred for these tumors. Endoscopic surgery followed by observation is acceptable for almost all NETS type I and II. At the same time, this approach is advisable only for small and highly differentiated neoplasms type III.

Recurrence and metastatic potential in Type 1 gastric neuroendocrine neoplasms

BACKGROUND

The aim of our study was to assess clinico-pathological and biochemical parameters of Type 1 Gastric Neuroendocrine Neoplasms (GNEN1) with respect to tumours propensity for recurrence and metastasis.

METHODS

Hospital charts of GNEN1 patients were reviewed at a single tertiary referral centre.

RESULTS

We included 114 consecutive patients (74 women; age at baseline 54.5 ± 12.7 years [mean ± SD]) with GNEN1. All tumours (n = 114) were well differentiated; Grade 1 (G1) accounted for 56 patients (49%), whereas 46 (40%) were Grade 2 (G2) and 12 (11%) of unknown Grade. Overall follow-up encompassed 45.3 ± 46 (mean ± SD) months in 84 patients who were subjected to annual surveillance; 44 (52%) developed recurrence in the stomach during follow-up with 22 experiencing multiple recurrences; three (2.6%) presented with metastases in locoregional lymph nodes (n = 3) and/or the liver (n = 2); No metastasis or death was reported during follow-up. Median recurrence-free survival (RFS) was 31 months (95% CI: 7.6-54.4). Among clinico-pathological and biochemical parameters investigated, endoscopic intervention compared with surgery (P-value = .009) and higher serum-gastrin levels (s-gastrin) at baseline and first-year follow-up were associated with recurrence (P-value = .022 and .003 respectively) and also shorter RFS (log-rank P = .009 for type of intervention and .014 for s-gastrin, respectively). Receiver Operator Curve analysis of s-gastrin levels at first-year follow-up for recurrence demonstrated an area under the curve of 0.702.

CONCLUSION

Despite the relatively high prevalence of G2 tumours, endoscopically and/or surgically treated GNEN1 remains an indolent disease with a low metastatic propensity and no disease-specific mortality reported in our series. Many patients though will experience local recurrence, warranting long-term endoscopic surveillance with s-gastrin biomarker being a complementary tool in recurrence prediction.

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).

Synchronous Triple Gastric Cancer Incorporating Mixed Adenocarcinoma and Neuroendocrine Tumor Completely Resected with Endoscopic Submucosal Dissection

The endoscopic and pathological features of early gastric mixed adenoneuroendocrine carcinoma (MANEC), as well as its carcinogenesis, remain largely unclear. Screening esophagogastroduodenoscopy was performed on an 80-year-old man, revealing 3 superficial elevated lesions. Endoscopic submucosal dissection (ESD) was performed, and the patient was diagnosed with intramucosal gastric cancer comprising mixed adenocarcinoma and neuroendocrine tumor, well-differentiated adenocarcinoma and well-differentiated adenocarcinoma, with negative margins. To our knowledge, this is the first report describing the endoscopic and pathological findings of synchronous triple gastric cancer incorporating mixed adenocarcinoma and neuroendocrine tumor completely resected with ESD.

Does the Novel Potassium-Competitive Acid Blocker Vonoprazan Cause More Hypergastrinemia than Conventional Proton Pump Inhibitors? A Multicenter Prospective Cross-Sectional Study

BACKGROUND/AIM

The long-term administration of proton pump inhibitors (PPIs) is useful for preventing recurrent reflux esophagitis. On the other hand, several adverse reactions, such as an increase in the blood gastrin level, have been reported. The aim of the present study was to examine the increase in the blood gastrin level due to the long-term administration of conventional PPIs compared with vonoprazan.

METHODS

A prospective cross-sectional study was conducted. We examined the blood gastrin levels of patients taking vonoprazan or conventional PPIs in whom the grade of atrophic gastritis had been endoscopically evaluated in the last year.

RESULTS

The blood gastrin level was significantly higher in the vonoprazan group than that in the PPI group in patients with milder or no atrophic gastritis, irrespective of the administration periods. However, no significant difference was observed between the groups in patients with severe atrophic gastritis.

CONCLUSION

Vonoprazan more markedly increased the blood gastrin level compared with conventional PPIs in patients with milder or no atrophic gastritis. This indicates that vonoprazan may have stronger acid-suppressing effects in such patients than conventional PPIs. Key Message: We should be aware of the potential development of hypergastrinemia during the long-term administration of vonoprazan, especially in patients with mild or no atrophic gastritis.

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.

Management of gastric and duodenal neuroendocrine tumors

Gastrointestinal neuroendocrine tumors (GI-NETs) are rare neoplasms, like all NETs. However, the incidence of GI-NETS has been increasing in recent years. Gastric NETs (G-NETs) and duodenal NETs (D-NETs) are the common types of upper GI-NETs based on tumor location. G-NETs are classified into three distinct subgroups: type I, II, and III. Type I G-NETs, which are the most common subtype (70%-80% of all G-NETs), are associated with chronic atrophic gastritis, including autoimmune gastritis and Helicobacter pylori associated atrophic gastritis. Type II G-NETs (5%-6%) are associated with multiple endocrine neoplasia type 1 and Zollinger-Ellison syndrome (MEN1-ZES). Both type I and II G-NETs are related to hypergastrinemia, are small in size, occur in multiple numbers, and are generally benign. In contrast, type III G-NETs (10%-15%) are not associated with hypergastrinemia, are large-sized single tumors, and are usually malignant. Therefore, surgical resection and chemotherapy are generally necessary for type III G-NETs, while endoscopic resection and follow-up, which are acceptable for the treatment of most type I and II G-NETs, are only acceptable for small and well differentiated type III G-NETs. D-NETs include gastrinomas (50%-60%), somatostatin-producing tumors (15%), nonfunctional serotonin-containing tumors (20%), poorly differentiated neuroendocrine carcinomas (< 3%), and gangliocytic paragangliomas (< 2%). Most D-NETs are located in the first or second part of the duodenum, with 20% occurring in the periampullary region. Therapy for D-NETs is based on tumor size, location, histological grade, stage, and tumor type. While endoscopic resection may be considered for small nonfunctional D-NETs (G1) located in the higher papilla region, surgical resection is necessary for most other D-NETs. However, there is no consensus regarding the ideal treatment of D-NETs.

Endoscopic diagnosis and management of type I neuroendocrine tumors

Type I gastric neuroendocrine tumors (TI-GNETs) are related to chronic atrophic gastritis with hypergastrinemia and enterochromaffin-like cell hyperplasia. The incidence of TI-GNETs has significantly increased, with the great majority being TI-GNETs. TI-GNETs present as small (< 10 mm) and multiple lesions endoscopically and are generally limited to the mucosa or submucosa. Narrow band imaging and high resolution magnification endoscopy may be helpful for the endoscopic diagnosis of TI-GNETs. TI-GNETs are usually histologically classified by World Health Organization criteria as G1 tumors. Therefore, TI-GNETs tend to display nearly benign behavior with a low risk of progression or metastasis. Several treatment options are currently available for these tumors, including surgical resection, endoscopic resection, and endoscopic surveillance. However, debate persists about the best management technique for TI-GNETs.

Chronic gastritis - an update

Helicobacter pylori is the main aetiologic factor for chronic gastritis worldwide. The degree of inflammation and the evolution of this form of chronic gastritis can vary largely depending on bacterial virulence factors, host susceptibility factors and environmental conditions. Autoimmune gastritis is another cause of chronic inflammation in the stomach, which can occur in all age groups. This disease presents typically with vitamin B12 deficiency and pernicious anaemia. The presence of anti-parietal cell antibodies is highly specific for the diagnosis. The role of H. pylori as a trigger for autoimmune gastritis remains uncertain. Other rare conditions for chronic gastritis are chronic inflammatory conditions such as Crohn's disease or on the background of lymphocytic or collagenous gastroenteropathies.

Clinical features and management of type I gastric carcinoids

Type I gastric carcinoids (TIGCs) are related to chronic atrophic gastritis and are characterized by hypergastrinemia and hyperplasia of enterochromaffin-like cells. TIGCs are the most frequently diagnosed of all gastric carcinoids, accounting for about 70-80 %. Endoscopically, TIGCs are present as small (<10 mm), polypoid lesions or, more frequently, as smooth, rounded submucosal lesions. Histologically, TIGCs arise in the deep mucosa, with some invading the submucosa. Most TIGCs are well-differentiated tumors, with metastasis being rare. Therefore, patients with TIGCs generally have an excellent prognosis. Among the currently available treatment options are total gastrectomy, partial resection, antrectomy, endoscopic resection, and endoscopic surveillance, although no consensus has been reached on their optimal management. Further studies are needed to develop better management options for patients with TIGC.