Diagnosis and Management of Gastrointestinal Neuroendocrine Neoplasms

Clinicopathological Characteristics, Survival and Prognostic Factors in Gastrointestinal Large Cell Neuroendocrine Carcinoma: A Retrospective Cohort Study

OBJECTIVES

Gastrointestinal large cell neuroendocrine carcinoma (GILCNEC) has a low incidence but high malignancy and poor prognosis. The main purpose of this study was to thoroughly investigate its clinicopathological features, survival and prognostic factors.

METHODS

Information on patients with GILCNEC was extracted from the Surveillance, Epidemiology, and End Result program, and prognostic factors were analyzed by analyzing clinicopathological data and survival functions. Finally, multivariate analysis was applied to identify independent risk factors associated with survival.

RESULTS

A total of 531 individuals were screened in our study from the Surveillance, Epidemiology, and End Result database. The primary sites are mainly from the following: esophagus in 39 (7.3%) patients, stomach in 72 (13.6%) patients, hepatobiliary in 51 (9.6%) patients, pancreas in 97 (18.3%) patients, small intestines in 27 (5.1%), and colorectum in 245 (46.1%) patients. Esophagus, stomach, pancreas, and colorectum large cell neuroendocrine carcinoma (LCNEC) were more common in males ( P = 0.001). Esophagus LCNEC had inferior overall survival (OS), whereas small intestine LCNEC was associated with better OS. The results of multivariate analysis showed that the American Joint Committee on Cancer Sixth Edition stage, surgery, and radiotherapy were independent prognostic indicators of OS in patients with GILCNEC ( P < 0.05).

CONCLUSIONS

The prognosis of patients with GILCNEC varies depending on the primary tumor site. American Joint Committee on Cancer Sixth Edition stage, surgery, and radiotherapy are independent prognostic factors of patients with GILCNEC. Although surgery and radiotherapy can prolong the survival of patients with GILCNEC, their prognosis remains poor, and further prospectively designed multicenter clinical studies are needed to indicate the decision for clinicians.

Risk factors for positive resection margins after endoscopic resection for gastrointestinal neuroendocrine tumors

BACKGROUND

In recent years, the incidence of gastrointestinal neuroendocrine tumors (GI-NETs) has remarkably increased due to the widespread use of screening gastrointestinal endoscopy. Currently, the most common treatments are surgery and endoscopic resection. Compared to surgery, endoscopic resection possesses a higher risk of resection margin residues for the treatment of GI-NETs.

METHODS

A total of 315 patients who underwent surgery or endoscopic resection for GI-NETs were included. We analyzed their resection modality (surgery, ESD, EMR), margin status, Preoperative marking and Prognosis.

RESULTS

Among 315 patients included, 175 cases underwent endoscopic resection and 140 cases underwent surgical treatment. A total of 43 (43/175, 24.57%) and 10 (10/140, 7.14%) patients exhibited positive resection margins after endoscopic resection and surgery, respectively. Multivariate regression analysis suggested that no preoperative marking and endoscopic treatment methods were risk factors for resection margin residues. Among the patients with positive margin residues after endoscopic resection, 5 patients underwent the radical surgical resection and 1 patient underwent additional ESD resection. The remaining 37 patients had no recurrence during a median follow-up of 36 months.

CONCLUSIONS

Compared with surgery, endoscopic therapy has a higher margin residual rate. During endoscopic resection, preoperative marking may reduce the rate of lateral margin residues, and endoscopic submucosal dissection may be preferred than endoscopic mucosal resection. Periodical follow-up may be an alternative method for patients with positive margin residues after endoscopic resection.

Comparing endoscopic mucosal resection with endoscopic submucosal dissection in colorectal adenoma and tumors: Meta-analysis and system review

AIMS

This study aimed to evaluate the safety, efficacy, and long-term outcomes of endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) for treating colorectal adenomas and tumors.

METHODS

A systematic literature review was conducted using databases including PubMed, Web of Science, and Embase. Parameters such as number of patients or lesions, histological diagnosis, lesion size, surgery time, en-bloc resection, R0 resection, severe postoperative complications, and local recurrence were extracted and pooled for analysis.

RESULTS

A total of 12 retrospective studies involving 1289 patients and 1850 lesions were included in the analysis. EMR was found to have a shorter operation time by 53.6 minutes (95% CI: 51.3, 55.9, P<0.001) and fewer incidences of severe postoperative complications such as perforation and delayed bleeding (OR = 0.40, 95%CI: 0.23, 0.71, P<0.001). On the other hand, ESD had higher rates of en-bloc resection (OR = 0.15, 95%CI: 0.07, 0.30, P<0.001) and R0 resection (OR = 0.32, 95%CI: 0.16, 0.65, P<0.001). Recurrence after EMR was found to be significantly higher than that after ESD surgery (OR = 5.88, 95%CI: 2.15, 16.07, P = 0.037).

CONCLUSIONS

The study suggests that the choice of surgical method may have a greater impact on recurrence compared to the pathological type, and that ESD may be more suitable for the treatment of malignant lesions despite its higher rates of severe postoperative complications and longer operation time.

Detection of Neuroendocrine Tumours by Enteroscopy: A Case Report

We present the case of a 62-year-old patient who developed melenas and in whom conventional endoscopic tests could not detect any bleeding lesion. In our case, capsule endoscopy and enteroscopy were the pivotal elements in establishing the diagnosis of a neuroendocrine tumour with an atypical location. As a result, it was possible to surgically remove the lesions at an early stage of the malignancy without metastatic disease and without the need for adjuvant therapy. Our case demonstrates the need for these new techniques in tumours of atypical location and aggressive course. Otherwise, this malignancy may be underdiagnosed until an advanced stage.

Virus-associated neuroendocrine cancers: Pathogenesis and current therapeutics

Neuroendocrine neoplasms (NENs) comprise malignancies involving neuroendocrine cells that often lead to fatal pathological conditions. Despite escalating global incidences, NENs still have poor prognoses. Interestingly, research indicates an intricate association of tumor viruses with NENs. However, there is a dearth of comprehension of the complete scenario of NEN pathophysiology and its precise connections with the tumor viruses. Interestingly, several cutting-edge experiments became helpful for further screening of NET for the presence of polyomavirus, Human papillomavirus (HPV), Kaposi sarcoma-associated herpesvirus (KSHV), Epstein Barr virus (EBV), etc. Current research on the neuroendocrine tumor (NET) pathogenesis provides new information concerning their molecular mechanisms and therapeutic interventions. Of note, scientists observed that metastatic neuroendocrine tumors still have a poor prognosis with a palliative situation. Different oncolytic vector has already demonstrated excellent efficacies in clinical studies. Therefore, oncolytic virotherapy or virus-based immunotherapy could be an emerging and novel therapeutic intervention. In-depth understanding of all such various aspects will aid in managing, developing early detection assays, and establishing targeted therapeutic interventions for NENs concerning tumor viruses. Hence, this review takes a novel approach to discuss the dual role of tumor viruses in association with NENs' pathophysiology as well as its potential therapeutic interventions.

Late-stage esophageal neuroendocrine carcinoma in a patient treated with tislelizumab combined with anlotinib: a case report

Esophageal neuroendocrine carcinoma (ENEC) is an extremely rare tumor with highly malignant potential, rapid growth, and a poor prognosis. Advanced extrapulmonary neuroendocrine carcinoma should be treated with chemotherapeutic regimens suitable for small cell lung cancer. However, ENEC has no clear second-line treatment options. The clinical application of immunotherapy and targeted therapy in small cell lung cancer has produced good therapeutic effects. We describe the case of an elderly woman with multiple metastatic advanced ENEC treated with tislelizumab combined with anlotinib as second-line therapy, achieving complete remission in a short period and long-term survival. In total, 21 cycles of tislelizumab combined with anlotinib were given to this patient. After two cycles, the patient's neuron-specific enolase level decreased from 181.8 to 22.9 µg/L and remained at normal levels throughout treatment. Progression-free survival and overall survival were 16 and 21 months, respectively, in this patient. No obvious side effects were observed. Thus, tislelizumab and anlotinib could represent a novel therapeutic option for advanced ENEC.

Biomarkers in gastroenteropancreatic neuroendocrine neoplasms

PURPOSE OF REVIEW

Gastroenteropancreatic neuroendocrine neoplasms (GEP-NEN) represent a heterogenous group of rare tumors emanating from neuroendocrine cells that are clinically silent for prolonged periods of time without detection. Traditional biomarkers lack sufficiently high enough specificity and sensitivity for these tumors and their secreted products. New molecules are sought to improve accuracy of detection and monitoring of GEP-NENs. The purpose of this review is to highlight recent advances in the discovery of novel biomarkers and their potential characteristics and utility as markers of GEP-NENs.

RECENT FINDINGS

Several recent GEP-NEN investigations regarding NETest demonstrate superior sensitivity and specificity in diagnosis and disease monitoring as compared with chromogranin A. Among several tissue-based emergent candidate molecules as biomarkers for GEP-NEN INSM1 has demonstrated consistently excellent characteristics when compared with traditional markers including chromogranin A, synaptophysin, and CD56.

SUMMARY

For the diagnosis and clinical monitoring of NEN, there still exists a considerable need for better biomarkers. Novel technology has resulted in a promising liquid biopsy for the detection and monitoring of GEP-NENs. The search for improved tissue biomarkers has resulted in identification of one potential candidate whereas several others remain in the investigatory phase.

Analysis of surgical treatment of appendix neuroendocrine neoplasms-17 years of single-center experience

BACKGROUND/AIM

This study investigated the clinicopathological characteristics and treatment of appendix neuroendocrine neoplasms in appendectomy specimens of our center.

MATERIALS AND METHODS

The clinicopathological data, including age, sex, preoperative clinical manifestation, surgical method, and histopathological examination results of 11 patients with appendix neuroendocrine neoplasms confirmed by surgery and pathology between November 2005 and January 2023, were retrospectively analyzed.

RESULTS

In the histopathological examination of 7277 appendectomy specimens, 11 cases (0.2%) had appendix neuroendocrine neoplasms. Among the 11 patients, 8(72.7%) were males, and 3(27.3%) were females, with an average age of 48.1 years. All patients underwent emergency surgery. A total of 9 patients underwent open appendectomy, including 1 patient who underwent second-stage simple right hemicolectomy after an appendectomy, and two who underwent laparoscopic appendectomy. All 11 patients were followed up for a period of 1 to 17 years. All patients survived without any indication of tumor recurrence.

CONCLUSION

Appendiceal neuroendocrine neoplasms are low-grade malignant tumors originating from neuroendocrine cells. They are rarely seen in clinical practice and are often treated based on acute and chronic appendicitis symptoms. These tumors are challenging to diagnose before surgery due to the lack of specificity in clinical manifestations and auxiliary examinations. The diagnosis generally depends on postoperative pathology and immunohistochemistry. Despite the diagnostic challenges, these tumors have a favorable prognosis.

Diagnostic Challenge of Small Bowel Neuroendocrine Tumor in a Young Female Patient

Neuroendocrine tumors (NETs) are rare cancers arising from neuroendocrine cells and are characterized by their ability to secrete functional hormones causing distinctive hormonal syndromes. The incidence of NET has increased over the years, and small bowel neuroendocrine tumor (SBNET) is one of the most challenging to detect due to its varied presentation and poor accessibility with traditional endoscopic methods. Patients with SBNET present with variable hormonal symptoms, such as diarrhea, flushing, and nonspecific abdominal pain, which often delay the diagnosis. We present the case of a young patient who underwent multidisciplinary workups leading to a successful diagnosis of SBNET promptly. The patient was a 31-year-old female who presented to the emergency department with complaints of nausea, vomiting, and sudden-onset, severe, sharp abdominal pain. CT scan of her abdomen showed an area of irregular intraluminal soft tissue density suspicious for a mass in the mid-small bowel. The patient's initial enteroscopy was normal. A video capsule endoscopy showed a small bowel mass, which was consistent with SBNET confirmed by pathology later. This case emphasizes the importance of considering SBNET as a differential diagnosis in young patients with nonspecific symptoms of abdominal pain and highlights the role of multidisciplinary approaches in achieving prompt diagnosis and treatment.

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.

Endoscopic treatment and management of rectal neuroendocrine tumors less than 10 mm in diameter

Rectal neuroendocrine tumors (rNETs) measuring less than 10 mm in diameter are defined as small rNETs. Due to the low risk of distant invasion and metastasis, endoscopic treatments, including modified endoscopic mucosal resection, endoscopic submucosal dissection, and other transanal surgical procedures, are effective. This review article proposes a follow-up plan according to the size and histopathology of the tumor after operation.

Contemporary outcomes of esophageal and gastroesophageal junction neuroendocrine tumors

Adenocarcinoma and squamous cell esophageal cancers have been extensively studied in the literature. Esophageal neuroendocrine (NET)/carcinoid tumors are less commonly studied and have only been described in small series. The purpose of this study was to describe the demographics and natural history of esophageal NETs, as well as optimal treatments. We hypothesized that surgical resection would be the best treatment of esophageal NETs. The National Cancer Database was used to identify adult patients with esophageal or gastroesophageal junction (GEJ) cancer from 2004 to 2018. Patients were characterized as carcinoid/NET, adenocarcinoma, or squamous cell cancer. Clinical and demographic characteristics were compared between the histology groups. The primary outcome was overall survival, which was assessed by multivariable Cox analysis. Multivariable Cox analysis was also used to analyze factors associated with survival among NET patients who underwent surgery. Among 206,321 patients with esophageal cancer, 1,563 were NETs (<0.01%). Relative to the other two histologies, NETs were associated with younger age, female sex, and advanced clinical stage at diagnosis. Multivariate analysis suggested that NETs were less likely to be treated with surgical resection (OR 0.51, P < 0.001). Nonetheless, surgical resection was associated with improved survival (HR 0.64, P = 0.003). Among patients with NETs who received surgery, neoadjuvant therapy was associated with improved overall survival (HR 0.38, P = 0.013). NET of the esophagus presents with more advanced disease than other common histologies. Among patients with nonmetastatic cancer, surgical resection appears to be the best treatment. Neoadjuvant systemic therapy may offer survival benefit, but future studies are necessary.

Anti-Hu-Associated Encephalomyelitis as a Presentation of Primary Extrapulmonary Small Cell Carcinoma of the Small Bowel: A Case Report

Small cell carcinoma (SCC) is a neuroendocrine tumor (NET) commonly found in the lung, known for rapid proliferation and early metastasis. Extrapulmonary small cell carcinomas (ESCC) are rare, with GI tract carcinomas exceedingly so. Due to the lack of clinical data on the treatment of ESCC, the standard regimen is the same as the SCC of the lung. Documented accounts of paraneoplastic encephalomyelitis associated with NETs are also uncommon. We present a patient who suffered from neurologic deficits before being diagnosed with paraneoplastic encephalomyelitis from a duodenal ESCC. The patient presented with ear pain and hematemesis. New symptoms arose after the resolution of initial symptoms, including shortness of breath and numbness. Autoimmune workup was positive for anti-Hu antibodies. A position emission tomography (PET) scan showed increased uptake in the duodenal region. Biopsy results from a duodenal ulcer revealed poorly differentiated neuroendocrine carcinoma with positive synaptophysin and strong positivity of Ki-67, consistent with ESCC. Numerous treatments, including platinum-based chemotherapy, yielded no neurologic improvement for the patient. This case details an atypical presentation of ESCC, which should be considered in patients suspected of paraneoplastic encephalomyelitis.

Gastric neuroendocrine neoplasms: a primer for radiologists

Gastric neuroendocrine neoplasms are uncommon tumors with variable differentiation and malignant potential. Three main subtypes are recognized: type 1, related to autoimmune atrophic gastritis; type 2, associated with Zollinger-Ellison and MEN1 syndrome; and type 3, sporadic. Although endoscopy alone is often sufficient for diagnosis and management of small, indolent, multifocal type 1 tumors, imaging is essential for evaluation of larger, high-grade, and type 2 and 3 neoplasms. Hypervascular intraluminal gastric masses are typically seen on CT/MRI, with associated perigastric lymphadenopathy and liver metastases in advanced cases. Somatostatin receptor nuclear imaging (such as Ga-68-DOTATATE PET/CT) may also be used for staging and assessing candidacy for peptide receptor radionuclide therapy. Radiotracer uptake is more likely in well-differentiated, lower-grade tumors, and less likely in poorly differentiated tumors, for which F-18-FDG-PET/CT may have additional value. Understanding disease pathophysiology and evolving histologic classifications is particularly useful for radiologists, as these influence tumor behavior, preferred imaging, therapy options, and patient prognosis.

Small bowel neuroendocrine neoplasm: what surgeons want to know

Neuroendocrine neoplasms of the small bowel are a diverse group of tumors with a broad spectrum of imaging findings and clinical implications. Most tumors originate in close proximity to the ileocecal valve and most commonly metastasize to the mesentery and liver. This review will highlight the imaging findings of primary and metastatic small bowel neuroendocrine neoplasm that are most relevant to the surgical team.

Extended surgical resection for nonfunctioning duodenal neuroendocrine tumor

Duodenal neuroendocrine tumors (NETs) account for <3% of all gastrointestinal NET. Most lesions are small-sized and are located in the first or second duodenal part. Tumoral grading, evaluated by Ki67 index, strongly influences patient’s outcome. Endoscopic resection is recommended for lesions measuring <2 cm, while pancreaticoduodenectomy should be the treatment of choice for large duodenal NET; Whipple procedure should be preferred in case of duodenal origin and contiguity with gastric antrum. Involvement of surrounding structures, as well as the presence of resectable liver metastases, does not contraindicate surgical resection. Herein we report a case of a 68-year-old male, presenting with an extensive mass of the descending pre-ampullary duodenal part, with involvement of the right colon and the presence of a pericholecystic single liver metastasis. In spite of such advanced disease, surgery on the patient was successful, with an uneventful postoperative outcome.

Gastroenteropancreatic Neuroendocrine Tumors

Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) are the most common type of neuroendocrine tumors and are being increasingly identified in clinical practice. The diagnosis, staging, management, and surveillance of GEP-NETs rely heavily on endoscopy, and consequently, it is important for gastroenterologists to have a solid understanding of these tumors. This article reviews the presentation, diagnosis, and management of both localized and advanced GEP-NETs, with increased emphasis on the role of endoscopy, to enable gastroenterologists and other practitioners to have the necessary tools for the care of patients with these tumors.

Metastatic rectal neuroendocrine carcinoma presenting with treatment-refractory immune thrombocytopenia: A case report and literature review

RATIONALE

Colorectal neuroendocrine cancer (CRNEC) accounts for < 1% of all colorectal cancers. It presents in advanced stages and carries a risk of poor survival. CRNEC may be diagnosed incidentally on imaging or routine endoscopy. When symptomatic, it may mimic colorectal adenocarcinoma. Syncope and immune thrombocytopenic purpura (ITP) have not previously been reported as clinical presentations.

PATIENT CONCERNS

A 57-year-old man with human immunodeficiency virus infection on treatment, seizure and stroke without residue presented for the evaluation of fall and syncope.

DIAGNOSIS

Physical examination revealed tachycardia, swelling, and ecchymosis of his proximal left lower extremity. Laboratory tests showed a new isolated thrombocytopenia of 26,000/mm3. Computed tomography for a trauma survey showed an incidental left posterior rectal wall mass. After hospital admission, his platelet count dropped to 14,000/mm3. A peripheral blood smear revealed low platelet count, no schistocytes or immature cells. ITP at a high risk for bleeding was diagnosed and treated with standard medical therapy but remained refractory. Bone marrow biopsy showed metastatic neuroendocrine carcinoma, likely from the rectum.

INTERVENTIONS

Patient received courses of high-dose dexamethasone and intravenous immunoglobulin. He also receive eleven units of platelet transfusion. A course of rituximab was administered. The platelet count response was suboptimal or short lived with drop to a nadir of 4000/mm3. However, after initiation of Eltrombopag, the thrombocytopenia resolved. Patient was started on etoposide, carboplatin, Atezolizumab. His hospital stay was complicated by neutropenia and sepsis, which was successfully treated.

OUTCOMES

He was discharged to subacute rehab in stable condition. About 4 months later, he was readmitted for severe thrombocytopenia, septic shock, and acute respiratory failure. Despite appropriate treatment, the patient deteriorated and expired.

CONCLUSION

CRNEC is a rare aggressive disease with dismal outcome that lacks standardized treatment. Metastasis to the bone marrow is uncommon and concomitant ITP has not been reported. We report a rare case of rectal neuroendocrine carcinoma metastatic to bone marrow associated with refractory ITP and review the relevant literature.

Underwater endoscopic mucosal resection for rectal neuroendocrine tumors (with videos): a single center retrospective study

BACKGROUND

Underwater endoscopic mucosal resection (UMER) is a new method of endoscopic resection to completely remove the lesion without submucosal injection. But few attempts have been carried out for rectal neuroendocrine tumors (rectal NETs).

METHODS

We retrospectively investigated data on the tumor characteristics and outcomes of patients with ≤ 10 mm rectal NETs who underwent UEMR or endoscopic submucosal dissection (ESD) from January 2019 to June 2021 in our institute.

RESULTS

The endoscopic resection rate was 100% in both UEMR and ESD groups. The histological complete resection rate of the UEMR group (95.5%) was lower than that of the ESD group (96.4%) with no significant difference. The average operation time, hospitalization time and operation cost of UEMR group were less than those of ESD group (P < 0.05). The incidence of postoperative abdominal pain and abdominal distention in the UEMR group was lower than that in the ESD group (P < 0.05). There was no significant difference in the incidence of delayed bleeding and perforation between the two groups. There was no local recurrence or distant metastasis in the two groups during the follow-up period.

CONCLUSIONS

Both the UEMR and ESD can effectively treat ≤ 10 mm rectal NETs with invasion depth confined to the mucosa and submucosa. UEMR is superior to ESD in operation time, hospitalization time, operation cost, postoperative abdominal pain and abdominal distention.

New insights in diagnosis and treatment of gastroenteropancreatic neuroendocrine neoplasms

Gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) are rare epithelial neoplasms derived from pluripotent endocrine cells along the gastrointestinal tract and pancreas. GEP-NENs are classified into well-differentiated neuroendocrine tumors and poorly differentiated neuroendocrine carcinomas. Despite overlapping morphological features, GEP-NENs vary in molecular biology, epigenetic, clinical behavior, treatment response, and prognosis features and remain an unmet clinical challenge. In this review, we introduce recent updates on the histopathologic classification, including the tumor grading and staging system, molecular genetics, and systemic evaluation of the diagnosis and treatment of GEP-NENs at different anatomic sites, together with some insights into the diagnosis of challenging and unusual cases. We also discuss the application of novel therapeutic approaches for GEP-NENs, including peptide receptor radionuclide therapy, targeted therapy, and immunotherapy with immune checkpoint inhibitors. These findings will help improve patient care with precise diagnosis and individualized treatment of patients with GEP-NENs.

Diagnosis and Surgical Treatment of Gastroenteropancreatic Neuroendocrine Neoplasms: A Literature Review

This review aimed to highlight the characteristics and surgical treatments of tumours, and answer questions regarding the assessment of gastrointestinal neuroendocrine neoplasms (NENs) and optimal therapy. NENs comprise tumours that can produce hormones and cause a secretory syndrome. The diagnostic method and accuracy differ depending on the site of occurrence; hence, the relevant scientific society has created NEN treatment guidelines for each organ. Gastroenteric pancreatic (GEP) NENs have been unified and classified together according to the 2019 World Health Organization classification. Treatment is based on complete tumour resection, and when metastatic or primary lesions cannot be completely resected, lesions and symptoms are treated. Except for surgery for NENs, chemotherapy, molecularly targeted drugs, transarterial chemoembolization, etc., have also been confirmed as treatments. GEP NEN treatment methods will continue to advance and change because of surgery and other advances in treatment and diagnostic methods.

Risk Factors Associated with the Development of Metastases in Patients with Gastroenteropancreatic Neuroendocrine Tumors: A Retrospective Analysis

Neuroendocrine tumors develop from systemic endocrine and nerve cells, and their occurrence has increased recently. Since these tumors are heterogeneous, pathological classification has been based on the affected organ. In 2019, the World Health Organization introduced a change expected to influence neuroendocrine tumor research, as gastroenteropancreatic neuroendocrine tumors are now included within a unified classification. This retrospective study aimed to investigate the characteristics (e.g., lymph node metastases and all other metastases) of gastroenteropancreatic neuroendocrine tumors using this new classification in 50 cases. Tumor size, depth, MIB-1 index, lymphatic invasion, venous invasion, and neuroendocrine tumor grade were significantly correlated with lymph node metastasis and other metastases. The venous invasion was more strongly correlated with lymph node metastasis and all other types of metastases than with lymphatic invasion. Identification rates for lymphatic invasion were considered lower because of structural problems such as lymphatic vessels being much thinner than veins. However, venous invasion was considered effective in compensating for the low identification rate in cases of lymphatic invasion. In future research, a unified classification and standardized framework for assessment will be important when analyzing the characteristics of neuroendocrine tumors, and large-scale studies are required.

Tumor neuroendocrino en recto simulando una neoplasia benigna: reporte de caso y revisión de la literatura

Los tumores neuroendocrinos se definen como un grupo heterogéneo de neoplasias de origen epitelial, provenientes de células enterocromafines diseminadas por todo el organismo, y representan alrededor del 1 al 4 % de todas las neoplasias. Su mayor distribución se encuentra en el tracto gastrointestinal, donde se localiza el 75 % de los tumores neuroendocrinos, siendo los ubicados en el recto, el 27 % de todos los que afectan el tracto gastrointestinal. A propósito de esta revisión de tema, presentamos el caso de un paciente de 71 años de edad, que consultó por sangrado rectal rojo rutilante, sin otra sintomatología asociada, y se le diagnosticó un tumor neuroendocrino grado 1, que se comportaba como una lesión benigna del recto.