Small bowel neuroendocrine tumors: From pathophysiology to clinical approach

Identification of TIMP1-induced dysregulation of epithelial-mesenchymal transition as a key pathway in inflammatory bowel disease and small intestinal neuroendocrine tumors shared pathogenesis

Inflammatory Bowel Disease (IBD) is believed to be a risk factor for Small Intestinal Neuroendocrine Tumors (SI-NET) development; however, the molecular relationship between IBD and SI-NET has yet to be elucidated. In this study, we use a systems biology approach to uncover such relationships. We identified a more similar transcriptomic-wide expression pattern between Crohn's Disease (CD) and SI-NET whereas a higher proportion of overlapping dysregulated genes between Ulcerative Colitis (UC) and SI-NET. Enrichment analysis indicates that extracellular matrix remodeling, particularly in epithelial-mesenchymal transition and intestinal fibrosis mediated by TIMP1, is the most significantly dysregulated pathway among upregulated genes shared between both IBD subtypes and SI-NET. However, this remodeling occurs through distinct regulatory molecular mechanisms unique to each IBD subtype. Specifically, myofibroblast activation in CD and SI-NET is mediated through IL-6 and ciliary-dependent signaling pathways. Contrarily, in UC and SI-NET, this phenomenon is mainly regulated through immune cells like macrophages and the NCAM signaling pathway, a potential gut-brain axis in the context of these two diseases. In both IBD and SI-NET, intestinal fibrosis resulted in significant metabolic reprogramming of fatty acid and glucose to an inflammatory- and cancer-inducing state. This altered metabolic state, revealed through enrichment analysis of downregulated genes, showed dysfunctions in oxidative phosphorylation, gluconeogenesis, and glycogenesis, indicating a shift towards glycolysis. Also known as the Warburg effect, this glycolytic switch, in return, exacerbates fibrosis. Corresponding to enrichment analysis results, network construction and subsequent topological analysis pinpointed 7 protein complexes, 17 hub genes, 11 microRNA, and 1 transcription factor related to extracellular matrix accumulation and metabolic reprogramming that are candidate biomarkers in both IBD and SI-NET. Together, these biological pathways and candidate biomarkers may serve as potential therapeutic targets for these diseases.

Unveiling a Small Bowel Obstruction: A Case of a Neuroendocrine Ileal Tumor

Neuroendocrine tumors (NETs) are rare, slow-growing tumors originating from the diffuse neuroendocrine cell system, predominantly affecting the digestive tract. Small bowel neuroendocrine tumors (SBNETs) may present with nonspecific symptoms, such as abdominal pain, or with intermittent intestinal obstruction. This case outlines the diagnostic journey of a septuagenarian male with prolonged abdominal symptoms and weight loss. Despite extensive investigation, a definitive cause remained elusive. Recurrent partial intestinal obstruction led to surgical exploration and segmental resection. Pathology confirmed a NET. The case underscores the importance of considering intestinal neoplasia in older patients with recurrent partial small bowel obstruction.

Management Strategies and Outcomes for Small Intestinal Neuroendocrine Tumours with Involvement of the Superior Mesenteric Vessels: A Systematic Review

Small intestinal neuroendocrine tumours (SI-NETs) are the most common small intestinal tumours. A particularly challenging subset of these tumours is those that involve the superior mesenteric artery or vein for which the role and feasibility of surgery are often questioned. This systematic review aimed to identify and evaluate the management strategies used for these complex SI-NETs. The identified studies showed positive outcomes with surgery and multimodality therapy.

When is surgery indicated in metastatic small intestine neuroendocrine tumor?

Small intestine neuroendocrine tumors are predominantly small but with high potential for distant metastases development. Diagnosis establishment in early-stage is often difficult and challenging. Small intestine neuroendocrine tumors often initially present with liver metastases. According to the Consensus Guidelines of the North American Neuroendocrine Tumor Society, in patients with liver metastases from unknown origin of primary neuroendocrine tumor, surgical exploration should be performed in order to identify the primary location, prevent small intestine obstruction, and treat one if already present. We present a case of a 69-year-old male patient diagnosed with liver and peritoneal metastases due to small bowel neuroendocrine tumor treated with surgery due to the presence of small intestine obstruction.

Incidental intraoperative finding of jejunal neuroendocrine tumors during elective ventral hernia repair

Neuroendocrine tumors (NETs) constitute ~0.5% of all diagnosed malignancies. In our case, a 72-year-old male, who was asymptomatic aside from mild left lower abdominal pain, was scheduled for elective ventral hernia repair, evident on computed tomography. The laparoscopic ventral hernia repair necessitated the conversion to laparotomy due to extensive adhesions and the incorporation of surgical mesh into the small bowel wall. The patient suffered from delayed small bowel injury resulting in the second emergent laparotomy when numerous calcified lesions were incidentally noted in the small bowel wall. Pathology confirmed Grade 1 well-differentiated NETs of the jejunum. This case highlights the importance of considering NETs as part of a differential diagnosis in patients with nonspecific symptoms and negative imaging studies. This case also emphasizes the importance of early detection of this rare pathology to improve prognosis and outcome.

Duodenal neuroendocrine tumor-tertiary care centre experience: A case report

BACKGROUND

Neuroendocrine neoplasms (NENs) are a heterogeneous group of neoplasms arising from neuroendocrine cells, which contribute a small fraction of gastrointestinal malignancies. Duodenal neuroendocrine tumors (dNETs) represent 2% of all gastroenteropancreatic NENs. NENs are heterogeneous in terms of clinical symptoms, location, and prognosis. Non-functional NETs are mostly asymptomatic and need a high degree of clinical suspicion. Diagnosis of NETs is by endoscopic, endosonographic biopsy, and histopathological examination with immunohistochemistry staining for synaptophysin and chromogranin A.

CASE SUMMARY

We present case reports of 5 patients obtained over a period of 10 years in our center with dNETs. One patient had moderately differentiated NET and the remaining four had well-differentiated NET. Surveillance endoscopy was recommended in all the patients and is kept under regular follow-up after performing endoscopic therapy using endoscopic mucosal resection in 4 of them and one patient was advised to undergo a Whipple procedure.

CONCLUSION

Recently, the number of reported cases of NETs has increased due to advancements in diagnostic modalities and prevalence because of longer survival duration. The management differs based on the site, size, proliferation grade, and locally invasive pattern. They are slow-growing tumors with a good overall prognosis. The prognosis correlates with local lymph node status and metastasis.

Small bowel neuroendocrine tumors: An analysis of clinical presentation, diagnostic workup and surgical approach—A single center retrospective study

Background

Neurocrine neoplasms (NEN) of the small bowel (SBNEN) are a rare entity and mostly asymptomatic. The aim of this study was to explore trends in the clinical presentation, diagnostic workup, surgical approach and oncological outcome in patients with SBNEN at our surgical department.

Materials and methods

All patients who underwent surgical resection for SBNEN from 2004 to 2020 at our department were enrolled in this single center retrospective study.

Results

A total of 32 patients were included in this study. In most cases, the diagnosis was based on incidental findings during endoscopy or radiographic imaging (n = 23; 72%). Twenty cases had a G1 tumor and 12 cases a G2 tumor. The 1-, 3- and 5-year overall survival (OS) were 96%, 86% and 81%, respectively. Patients with a tumor more than 30 mm had a significantly lower OS (p = 0.01). For G1 tumors, the estimated disease-free survival (DFS) was 109 months. Again, the DFS was significantly lower when the tumor had more than 30 mm in diameter (p = 0.013).

Conclusion

Due to the mostly asymptomatic presentation, the diagnostic workup can be difficult. An aggressive approach and a strict follow-up seem to be important for the oncological outcome.

Morphological and immunohistochemical features of neuroendocrine neoplasms in gastroenteropancreatic tract

BACKGROUND AND AIMS

Neuroendocrine neoplasms (NENs) result from neuroendocrine cell neoplastic proliferation, with both characteristics of endocrine and nerve cells. NENs arise in different localizations but the most common site is the gastrointestinal tract, including the pancreas. The morphology and frequency of NENs in our hospital were evaluated, as well as the correlation between lymph node status and Ki67 proliferative index.

MATERIALS AND METHODS

Retrospectively, we analyzed NEN pathohistological reports of patients who underwent surgical excision of gastroenteropancreatic tumors in the Clinical Center of Vojvodina in Novi Sad, from 2011 to 2018. The descriptive and correlation statistics were done. Chromogranin A, synaptophysin, CD56, and Ki67 were usually used as immunohistochemical markers.

RESULTS

The study registered 78 surgical specimens. The average age of patients was 58.88 (±17) years, whereby 53.8% were males. The most frequent site was the pancreas (29.5%), followed by the large intestine (26.9%). The mean tumor size was 3.71 (±3.13) cm. No significance was found in tumor differentiation degree (G1 = 32.1%, G2 = 26.9%, and G3 = 29.5%). Lymph node metastases were found in 47.44%. Positive correlation was found between the Ki67 index and the percentage of positive lymph nodes (r = 0.343, p = 0.046, p < 0.05, respectively). The correlation between tumor size and lymph node metastases revealed no significance in our study (r = 0.015, p = 0.480, p > 0.05, respectively).

CONCLUSION

Most NENs lymph node metastases originated from tumors with a high Ki67 index. The results confirm the use of proliferative index Ki67 as a prognostic marker for the presence of metastases, disease progression, and neuroendocrine tumor prognosis.

Differential to Terminal Ileitis: Terminal Ileum Neuroendocrine Tumor Identified on Screening Colonoscopy

Background: Asymptomatic patients at average risk of developing colorectal cancer are encouraged to undergo screening colonoscopy beginning at age 45 years. While ileal intubation is often considered the gold standard for a complete colonoscopy, the relatively low diagnostic yield has prevented widespread adoption. Small bowel cancers, including neuroendocrine tumors, may present incidentally as terminal ileitis on routine colonoscopy with terminal ileum intubation. Neuroendocrine tumors, the most common primary neoplasm of the small intestine, are often asymptomatic or present as nonspecific abdominal pain in the sixth or seventh decade of life. Case Report: A 51-year-old asymptomatic male with unremarkable physical examination underwent screening colonoscopy that revealed scattered ulcerations of the terminal ileum. Immunohistochemistry of the lesion was consistent with well-differentiated neuroendocrine tumor, World Health Organization Grade I. DOTATATE positron emission tomography/computed tomography demonstrated avid adjacent right mesenteric lymph node and avid focal pancreatic body lesion. Fine-needle biopsy and immunohistochemistry of the pancreatic lesion confirmed neuroendocrine tumor, while the mesenteric lymph node was found to be benign. The patient underwent robotic-assisted ileocolic resection and has ongoing surveillance of the pancreatic lesion. Conclusion: Terminal ileitis encompasses a host of pathologic processes, including inflammatory states, infectious disease, malignancy, and vasculitis. Importantly, small bowel cancer is an increasing cause of terminal ileitis. Screening colonoscopy with ileal intubation can be a valuable tool for early detection of these lesions.

Radiologic Review of Small Bowel Malignancies and Their Mimicking Lesions

Because of their small size, small bowel malignancies are often easily missed when radiologists read CT images, which can lead to errors in the normal small bowel due to their similar enhancement to the small bowel or non-specific enhancement. In addition, small bowel malignancies are sometimes mistaken for masses of other origins, such as the uterus, rectum, or omentum. In this article, we describe various small-bowel malignancies, their mimicking lesions and the typical and atypical features on CT imaging along with their clinical manifestations.

Epidemiology of small intestine cancer in Iran

Background

Little is known about the epidemiology of small intestine (SI) cancer in Iran, a rare cancer entity worldwide.

Aims

The aim of the present study was to investigate the incidence patterns and survival rates of SI cancer in Iran through a population‐based study.

Methods and Results

Data on all reported cases of SI cancer were extracted from the Iran National Cancer Registry based on ICD‐O‐3 codes. Age‐standardized incidence rates (ASIR), age‐specific incidence rates, standardized rate ratios (SRR), time trends, and absolute survival rates were calculated.

During 2005–2015, a total of 4928 SI cancers (ASIR: 0.87/100 000) were diagnosed, including 2835 carcinomas (ASIR: 0.51), 214 neuroendocrine malignancies (ASIR: 0.04), 228 sarcomas (ASIR: 0.04), and 704 lymphomas (ASIR: 0.11). Carcinomas and lymphomas occurred more frequently in men than in women (SRR: 1.37/100 000 and 1.85/100 000, respectively), while the other two histological subtypes were almost equally distributed. 78% of carcinomas and 53% of neuroendocrine tumors were located in the duodenum. Sarcomas occurred most frequently in the jejunum (41%), while lymphomas were most frequently in the ileum (44%). From 2005 to 2015, the number of reported cases of SI cancer increased by 9.6% per year. The median age of diagnosis for women and men was 61. The absolute 5‐year survival rate was 35.3%, varying by sex, age, and subtype. Carcinomas had the lowest survival rate (24.1%) while neuroendocrine carcinomas had the highest survival rate (69.7%).

Conclusion

Epidemiological patterns of SI cancer in Iran differed slightly from patterns in the United States and the United Kingdom. In contrast to other countries, the neuroendocrine form is presented as the rarest subtype in Iran. The overall incidence of SI cancer was lower in Iran than in high‐income countries. In contrast, the average prognosis of SI cancer was worse in Iran, indicating the need to improve early detection, diagnosis, and treatment.

Role of Resection of the Primary in Metastatic Well-Differentiated Neuroendocrine Tumors

OBJECTIVE

Resection of the primary (RP) in metastatic neuroendocrine tumor (NET) is controversial. The aim was to evaluate survival outcomes for RP in metastatic NET patients.

METHODS

Data were obtained from US hospitals at the National Cancer Database between 2004 and 2014. χ2, analysis of variance tests, univariate, and multivariate cox proportional hazards models were evaluated. Kaplan-Meier curves and log-rank tests conducted to compare the survival difference of patient characteristics.

RESULTS

A total of 2361 patients were identified. The mean age was 62.1 years (standard deviation, 13 years), male-to-female ratio 1:1; 33% were small intestine, 26.3% pancreas, and 24.4% lung; 69.6% were well-differentiated; and 42.5% underwent RP. The 5-year overall survival (OS) was significantly improved for patients who underwent RP in small intestine (5-year OS, 63.9% vs 44.2%), lung (5-year OS, 65.4% vs 20.2%), and pancreas tumors (5-year OS, 75.6% vs 30.6%). On multivariate analysis, RP (hazard ratio, 0.46; 95% confidence interval, 0.29-0.73; P < 0.001), female, year of diagnosis 2010-2014, margin, Charlson-Deyo score less than 2, and age less than 51 years, were associated with better OS.

CONCLUSIONS

Resection of the primary in metastatic well-differentiated NET is associated with improved OS compared with no RP.

Management of small bowel adenocarcinoma: making the most of the available evidence to inform routine practice

PURPOSE OF REVIEW

Small bowel adenocarcinoma (SBA) is a rare disease, for which few studies have been conducted so far. Therefore, most treatment recommendations have been extrapolated from trials in colorectal cancer. In this review, we revise available data that could improve the management of SBA, with a particular focus on systemic therapy.

RECENT FINDINGS

For advanced/irresectable disease, first-line doublet chemotherapy remains standard of care. It is uncertain whether extending treatment to triplet chemotherapy brings added benefit. Pembrolizumab is an accepted treatment modality for mismatch repair-deficient tumors, yet might also be active in microsatellite stable tumors. More trials with immunotherapy are underway. Although there is no place for anti-EGFR monotherapy, the addition of cetuximab to chemotherapy should be investigated further. Two trials suggest an added value of bevacizumab to chemotherapy, yet larger trials are needed to confirm these data. For localized disease, the role of (neo)adjuvant chemotherapy is under investigation.

SUMMARY

For decades, patients with SBA have probably been treated suboptimal by basing treatment recommendations on data from colorectal cancer. An effort for SBA-specific trials and/or inclusion of SBA patients in basket trials is of utmost importance in order to improve outcome for these patients.

A case report on metastatic ileal neuroendocrine neoplasm to the breast masquerading as primary breast cancer: A diagnostic challenge and management dilemma

RATIONALE

Metastatic neuroendocrine neoplasms (NENs) to the breast are very rare entities comprising only 1% to 2% of all metastatic breast tumors. In this article, we describe a case of a neuroendocrine ileal neoplasm metastatic to breast and liver, with breast metastatic tumor to be the initial manifestation of the disease.

PATIENT CONCERNS

We herein report a rare case of a female patient admitted to our department with a palpable painful mass on her left breast.

DIAGNOSIS

The surgical and histological investigation revealed a metastatic neuroendocrine neoplasm to the breast originated from terminal ileum.

INTERVENTIONS

A left lumpectomy, right hemicolectomy, cholecystectomy, left hepatectomy along with liver metastasectomies (V, VI, VIII) plus radiofrequency ablation of lesions to the right liver lobe plus standard lymphadenectomy was performed.

OUTCOMES

Considering the advanced stage of the disease, the patient received an adjuvant therapy of somatostatin analog plus everolimus. Under the guidance of oncological consultation, patients follow-up with CT and MRI scan and clinical re-evaluations in the first 3 and 6 months, substantiates no evidence of recurrence and she presents herself asymptomatic.

LESSONS

An appropriate level of suspicion and selective immunohistochemistry in these cases, particularly where no prior history of a known primary neuroendocrine neoplasm occurs, may help to diagnose a previously undetected neuroendocrine tumor elsewhere in the body and provide guidance for the appropriate treatment selection.

Neuroendocrine neoplasms: current and potential diagnostic, predictive and prognostic markers

Some biomarkers for functioning and non-functioning neuroendocrine neoplasms (NENs) are currently available. Despite their application in clinical practice, results should be interpreted cautiously. Considering the variable sensitivity and specificity of these parameters, there is an unmet need for novel biomarkers to improve diagnosis and predict patient outcome. Nowadays, several new biomarkers are being evaluated and may become future tools for the management of NENs. These biomarkers include (1) peptides and growth factors; (2) DNA and RNA markers based on genomics analysis, for example, the so-called NET test, which has been developed for analyzing gene transcripts in circulating blood; (3) circulating tumor/endothelial/progenitor cells or cell-free tumor DNA, which represent minimally invasive methods that would provide additional information for monitoring treatment response and (4) improved imaging techniques with novel radiolabeled somatostatin analogs or peptides. Below we summarize some future directions in the development of novel diagnostic and predictive/prognostic biomarkers in NENs. This review is focused on circulating and selected tissue markers.

A 41-Year-Old Patient with a Rare Cause of Severe Abdominal Sepsis Misdiagnosed as PID

Infectious pelvic inflammatory disease is a common condition and a frequent cause of abdominal pain in a young female patient. In a patient who has not completed family planning, the diagnosis is often made with a low threshold and treatment started on a low suspicion of diagnosis to avoid a negative impact on fertility. Here, we present a case of a 41-year-old woman who was misdiagnosed with infectious pelvic inflammatory disease and treated ineffectively with antibiotics when the underlying condition of her persistent abdominal pain was a midgut neuroendocrine tumor that had caused bowel perforation and formation of an abscess in the pouch of Douglas.

Gastrointestinal manifestations of neuroendocrine tumours: their investigation and management

The incidence of neuroendocrine tumours (NETs) is on the rise in the UK. Patients with NETs need to be managed by a team of clinical specialties. There are a number of challenging gastrointestinal (GI) manifestations related to NETs that can occur in these patients, but a limited literature base exists to guide clinicians.Whilst life expectancy can be several years for patients with NETs, the GI symptoms can have a significant impact on their quality of life. It is therefore imperative to be familiar with the common GI manifestations associated with NETs, so symptoms can be appropriately managed with an overall aim of restoring the patient's quality of life.