Appendiceal Mixed Adeno-Neuroendocrine Carcinoma: A Population-Based Study of the Surveillance, Epidemiology, and End Results Registry

Peritoneal metastatic mixed adenoneuroendocrine carcinoma treated with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy: a case report

A 61-year-old man presented with abdominal distension without any symptoms. On colonoscopy and computed tomography findings, it was clinically diagnosed as peritoneal metastasis of sigmoid colon cancer, and diagnostic laparoscopy was performed. Only the peritoneum was partially resected, and the pathology was signet ring cell carcinoma with predominantly local mucinous carcinoma component. However, the patient complained of persistent symptoms and, despite the progress of chemotherapy, the peritoneal dissemination worsened, and additional cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (HIPEC) was performed. Mixed adenoneuroendocrine carcinomas (MANECs) were reported in the appendix with perforated visceral peritoneum. After additional chemotherapy, the patient was discharged. Patients with advanced MANEC with peritoneal spreading may benefit from aggressive treatment by cytoreduction surgery with HIPEC, followed by intravenous chemotherapy.

Discussion on the benefits of different treatment strategies in elderly and non-elderly patients with appendix MiNEN: a retrospective study based on SEER database

PURPOSE

To investigate the benefits of surgery alone and postoperative chemotherapy in elderly and non-elderly patients with appendiceal mixed neuroendocrine non-neuroendocrine neoplasms (MiNENs) and analyze the factors affecting the prognosis of patients with MiNEN of the appendix.

METHODS

Based on the Surveillance, Epidemiology, and End Results database (SEER) of the National Cancer Institute of the USA, 389 patients with appendiceal MiNENs from 2000 to 2016 were collected. All patients were distributed in the elderly group (≥ 60 years old) and the non-elderly group (< 60 years old) according to their age. The prognosis of the two groups of patients who received simple surgery and postoperative chemotherapy was analyzed and compared. The two treatment methods of the two tranches were matched by propensity score matching method. The effect of different treatment ways on the prognosis of sick persons was compared. The survivorship curves were painted by the Kaplan Meier method, log rank test was used to analyze the subsistence discrepancy of each group, and COX proportional risk model was used to analyze the factors affecting the prognosis of patients with appendiceal MiNENs.

RESULTS

No matter the overall survival rate (OS) or cancer-specific mortality (CSM) of the two treatment schemes, the prognosis of patients in the only surgery group was meaningfully higher than that in the postoperative chemotherapy group, with statistically significant difference in component comparison (χ² = 16.496, χ² = 16.860, P < 0.001). After propensity score matching of patients in each group, there was no striking discrepancy in the OS of patients in the only surgery group compared with those in the postoperative chemotherapy group, regardless of whether they were elderly patients or non-elderly patients (χ² = 3.205, χ² = 1.521, all P > 0.05), the CSM consequences are fitting in with the OS. The consequences of the multivariate COX regression model showed that age (≥ 60 years old), sex (female), high histological grade, and lymph node positive were all the influencing factors for the poor OS of patients with MiNEN; the CSM results are consistent with the OS.

CONCLUSION

For patients with appendix MiNEN, whether elderly or non-elderly patients (especially for non-elderly patients), surgical treatment may be a better choice.

Comprehensive analysis of mixed neuroendocrine non-neuroendocrine neoplasms (MiNENs): A SEER database analysis of 767 cases

Background

Mixed neuroendocrine non-neuroendocrine neoplasm (MiNEN) is an extremely rare entity, consisting of neuroendocrine and non-neuroendocrine components. It can occur in various organs throughout the body, with a rising incidence. Its clinical management is a rapidly growing field of interest; however, large-scale patient cohorts are still missing to guide clinical practice.

Patients and methods

The demographic, clinicopathological, and survival information of all patients diagnosed with MiNEN in the national Surveillance, Epidemiology, and End Results (SEER) program database (2000-2017) were extracted and further analyzed. The information of the patients before and after 2010 was compared to understand the epidemiological changes of MiNEN. The characteristics of MiNEN originating in different organs were compared. The clinical significance of surgical resection for metastatic MiNENs was also analyzed.

Results

A total of 1081 patients were screened, and after applying the exclusion criteria, 767 patients were finally analyzed. There was no obvious sex preference (49.2% vs 50.8%, p>0.05) and the majority of the patients were Caucasians (n=627, 81.7%). A total of 88.3% of the patients were older than 50 years old, and the median age was 60 years. 79.3% of the tumors are located in the distal digestive tract, and 67.7% were grade 3/4. Distant metastasis was presented in 33.9% of the patients at diagnosis. A total of 88% of the patients underwent surgical treatments. The number of patients increased 10-fold between 2000 and 2017. There was no significant difference in sex, race, stage, or surgical treatments among the patients diagnosed before and after 2010. More patients older than 60 years were diagnosed after 2010 (p=0.009). The median survival was 61.0 ± 9.8 months for the whole cohort. After multivariate analysis, older age (>60 years, p<0.01), more advanced stage (p<0.01), grade 3/4 (p<0.01), and non-surgical treatment (p<0.01) were independent risk factors for poorer survival. The appendiceal MiNENs showed the best prognosis. A total of 260 metastatic MiNENs were further analyzed. Only patients with metastatic MiNENs originating from the appendix had a potential benefit from surgical resection, compared to other sites (p=0.05).

Conclusion

This study provides the epidemiological, clinicopathological, and survival information of the largest number of MiNEN patients. Although MiNEN is an extremely rare malignant neoplasm, its incidence increases rapidly. The majority of the patients suffered from advanced-stage disease, which highlights the need for improvement of early detection in the future. The appendix is the most common primary site of MiNEN, and surgical resection for selected metastatic MiNEN originating in the appendix has favorable survival outcomes.

Goblet Cell Adenocarcinoma of the Appendix: A Systematic Review and Incidence and Survival of 1,225 Cases From an English Cancer Registry

Background

Goblet cell adenocarcinoma (GCA) of the appendix is a rare and aggressive tumour with varying nomenclature and classification systems. This has led to heterogeneity in published data, and there is a lack of consensus on incidence, survival, and management.

Methods

We provide an overview of GCA with a comprehensive systematic review using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) methodology and a retrospective analysis of all cases recorded in the English National Cancer Registration and Analysis Service database between 1995 and 2018. The Kaplan–Meier estimator was used to calculate overall survival, and Cox proportional hazards regression was used to identify prognostic factors.

Results

The systematic review demonstrated an incidence of 0.05–0.3 per 100,000 per year among North American registry studies. The 1-, 3-, and 5-year survival rate was 95.5%, 85.9%–87.6%, and 76.0%–80.6%, respectively. Age, stage, and grade were identified as prognostic factors for survival. Our analysis included 1,225 cases. Age-standardised incidence was 0.0335 per year in 1995 and gradually rose to 0.158 per year in 2018. The 1-, 3-, and 5-year survival rate was 90.0% [95% confidence interval (95% CI): 85.4–94.0], 76.0% (95% CI: 73.8–80.9), and 68.6% (95% CI: 65.9–72.2), respectively. On univariate Cox regression analyses, female sex, stage, and grade were associated with worse overall survival. On multivariate analysis, only stage remained a statistically significant prognostic factor.

Conclusions

GCA of the appendix is rare, but incidence is increasing. We report a lower incidence and survival than North American registry studies. Higher stage was associated with decreased survival. Further prospective studies are required to establish optimal management.

Surgery in Patients with Gastro-Entero-Pancreatic Neuroendocrine Carcinomas, Neuroendocrine Tumors G3 and High Grade Mixed Neuroendocrine-Non-Neuroendocrine Neoplasms

OPINION STATEMENT

In the 2019 WHO guidelines, the classification of gastro-entero-pancreatic neuroendocrine neoplasms (GEP NEN) has changed from one being based on Ki-67 proliferation index alone to one that also includes tumor differentiation. Consequently, GEP NENs are now classified as well-differentiated neuroendocrine tumor (NET), NET G1 (Ki-67 <3%), NET G2 (Ki-67 3-20%) and NET G3 (Ki-67 >20%), and poorly differentiated neuroendocrine carcinoma (NEC) (Ki-67 >20%). It has been suggested that NET G3 should be treated as NET G2 with respect to surgery, while surgical management of NEC should be expanded from local disease to also include patients with advanced disease where curative surgery is possible. High grade mixed neuroendocrine-non-neuroendocrine neoplasms (MiNEN) have a neuroendocrine and a non-neuroendocrine component mostly with a poor prognosis. All studies evaluating the effect of surgery in NEC and MiNEN are observational and hold a risk of selection bias, which may overestimate the beneficial effect of surgery. Further, only a few studies on the effect of surgery in MiNEN exist. This review aims to summarize the data on the outcome of surgery in patients with GEP NET G3, GEP NEC and high grade MiNEN. The current evidence suggests that patients with NEN G3 and localized disease and NEN G3 patients with metastatic disease where curative surgery can be achieved may benefit from surgery. In patients with MiNEN, it is currently not possible to evaluate on the potential beneficial effect of surgery due to the low number of studies.

Mixed neuroendocrine–nonneuroendocrine neoplasms of the gastrointestinal system: An update

Mixed neuroendocrine-nonneuroendocrine neoplasms (MiNENs) of the digestive tract are a rare heterogeneous group of tumors that present many challenges in terms of diagnosis and treatment. Over the years, the diagnostic criteria, classification, and clinical behavior of these tumors have been the subjects of ongoing debate, and the various changes in their nomenclature have strengthened the challenges associated with MiNENs. This review is performed to provide an understanding of the key factors involved in the evolution of the designation of these tumors as MiNEN, highlight the current diagnostic criteria, summarize the latest data on pathogenesis and provide information on available treatments. Moreover, this work seeks to increase the awareness about these rare neoplasms by presenting the clinicopathological features and prognostic factors that play important roles in their behavior and discussing their different regions of origin in the gastrointestinal system (GIS). Currently, the MiNEN category also includes tumors in the GIS with a nonneuroendocrine component and epithelial tumors other than adenocarcinoma, depending on the organ of origin. Diagnosis is based on the presence of both morphological components in more than 30% of the tumor. However, this value needs to be reconfirmed with further studies and may be a limiting factor in the diagnosis of MiNEN by biopsy. Furthermore, available clinicopathological data suggest that the inclusion of amphicrine tumors in the definition of MiNEN is not supportive and warrants further investigation. The diagnosis of these tumors is not solely based on immunohistochemical findings. They are not hybrid tumors and both components can act independently; thus, careful grading of each component separately is required. In addition to parameters such as the metastatic state of the tumor at the time of diagnosis and the feasibility of surgical resection, the aggressive potential of both components has paramount importance in the choice of treatment. Regardless of the organ of origin within the GIS, almost MiNENs are tumors with poor prognosis and are frequently encountered in the elderly and men. They are most frequently reported in the colorectum, where data from molecular studies indicate a monoclonal origin; however, further studies are required to provide additional support for this origin.

The association between appendicitis severity and patient age with appendiceal neoplasm histology-a population-based study

PURPOSE

Recent studies have reported alarming appendiceal tumor rates associated with complicated acute appendicitis, especially in patients presenting with a periappendicular abscess. However, the data on histology of appendiceal tumors among acute appendicitis patients is limited, especially in patient cohorts differentiating between uncomplicated and complicated acute appendicitis. We have previously reported the association of increased appendiceal tumor prevalence with complicated acute appendicitis in this population-based study. The objective of this secondary analysis was to evaluate the association of both appendicitis severity and patient age with appendiceal tumor histology.

METHODS

This nationwide population-based registry study (The Finnish Cancer Registry) was conducted from 2007 to 2013. All appendiceal tumors (n = 840) and available medical reports (n = 504) of these patients at eight study hospitals were previously evaluated, identifying altogether 250 patients with both acute appendicitis and appendiceal tumor.

RESULTS

The severity of acute appendicitis was significantly associated with more malignant tumor histology. The risk of adenocarcinoma or pseudomyxoma was significantly higher among patients with periappendicular abscess (OR 15.05, CI 95% 6.98-32.49, p < 0.001) and patients presenting with perforated acute appendicitis (OR 4.09, CI 95% 1.69-9.90, p = 0.0018) compared to patients with uncomplicated acute appendicitis. Similarly, patient age over 40 years was significantly associated with the risk of adenocarcinoma and pseudomyxoma (OR 26.46, Cl 95% 7.95-88.09, p < 0.001). Patient sex was not associated with a more malignant appendiceal tumor histology (p = 0.67).

CONCLUSION

More malignant appendiceal tumor histology of adenocarcinoma or pseudomyxoma was significantly associated with patient age over 40 years and complicated acute appendicitis, especially periappendicular abscess.

GNEN-1: a spontaneously immortalized cell line from gastric neuroendocrine neoplasia

Mixed neuroendocrine-non-neuroendocrine neoplasms (MINEN) are rare tumors that consist of at least 30% of both neuroendocrine and non-neuroendocrine components. The data concerning the pathogenesis of MINEN suggest a monoclonal origin. We describe a spontaneously immortalized cell line derived from gastric MINEN called GNEN-1. Primary tumor consisted of components of high-grade neuroendocrine carcinoma and adenocarcinoma. The GNEN-1 cell line was initiated from metastatic tumor cells of peritoneal fluid and expresses a purely neuroendocrine phenotype. The GNEN-1 cell line grows as monolayers and has retained the neuroendocrine phenotype with positivity for chromogranin A in immunohistochemistry. Electron microscopy showed cytoplasmic dense core granules and axon hillocks. The karyotype revealed alterations typical of both adenocarcinoma and neuroendocrine carcinoma such as trisomy 7 and 8. GNEN-1 cells were also positive for stanniocalcin-1, a marker of poor prognosis in gastric carcinomas. Expression of several markers related to neuroendocrine tumors was found. There have been only a few studies on the pathogenesis of MINEN and management of the disease due to the rarity of this tumor type. Here we describe for the first time an immortalized cell line derived from mixed gastric NEN. The GNEN-1 line offers a tool for future research on gastric NEN.

Mixed adenoneuroendocrine carcinoma (MANEC) of the lower gastrointestinal tract: A systematic review with Bayesian hierarchical survival analysis

BACKGROUND

Mixed adeno-neuroendocrine carcinomas (MANEC) are a subgroup of mixed neuroendocrine non-neuroendocrine neoplasms (MiNEN) described as mixed neoplasms containing dual neuroendocrine and non-neuroendocrine components. The aim of this study was to appraise the prevalence of MANEC in the lower gastrointestinal (GI) tract and provide reliable estimates of survival.

METHOD

A systematic review was undertaken in accordance with PRISMA guidelines using PubMed, Embase, Cochrane Library of Systematic Review, Web of Science, and Scopus databases, and a Bayesian hierarchical survival pooled analysis was performed.

RESULTS

Of 182 unique records identified, 71 studies reporting on 752 patients met the inclusion criteria. Mean age was 64.2 ± 13.6, with a male-to-female ratio of 1.25. Overall, 60.3% of MANEC were located in the appendix, 29.3% in the colon, and 10.4% in the anorectum. More than a quarter (29%) of patients had stage IV disease at diagnosis, with higher prevalence in appendiceal than colonic and anorectal primaries. More than 80% had a high-grade (G3) endocrine component. Of the 152 patients followed up for a median of 20 months (interquartile range limits, 16.5-32), median overall survival was 12.3 months (95% credible interval [95%CrI], 11.3-13.7), with a 1.12 [95%CrI, 0.67-1.83] age-adjusted hazard ratio between metastatic and non-metastatic MANEC. Stage IV disease at diagnosis was more prognostically unfavorable in cases of colonic compared to anorectal origin.

CONCLUSION

MANEC is a clinically aggressive pathological entity. The results of this study provide new insights for the understanding of tumor location within the lower GI tract and its prognosis in terms of overall survival.

Risk of appendiceal neoplasm after interval appendectomy for complicated appendicitis: A systematic review and meta-analysis

BACKGROUND

Non-operative management is often the treatment of choice in cases of complicated appendicitis and routine interval appendectomy is not usually recommended. Actually, recent studies show an alarming number of appendiceal neoplasms following interval appendectomy. The aim of this study is to evaluate the prevalence of appendiceal neoplasms and their histological types after interval appendectomy for complicated appendicitis in adults.

METHODS

A comprehensive literature search of the PubMed, Scopus and Web of Science databases was conducted according to the PRISMA statement. Studies reporting appendiceal neoplasm rates after interval appendectomy and histopathological characteristics were included. The most recent World Health Organization (WHO) classification of malignant tumours was considered. A pooled prevalence analysis for both prevalence and pathology was performed.

RESULTS

A total of eight studies was included: seven retrospective series and one randomized controlled trial. The pooled prevalence of neoplasms after interval appendectomy was 11% (95% CI 7-15; I² = 37.5%, p = 0.13). Appendiceal mucinous neoplasms occurred in 43% (95% CI 19-68), adenocarcinoma in 29% (95% CI 6-51), appendiceal neuroendocrine neoplasm in 21% (95% CI 6-36), globet cell carcinoma in 13% (95% CI -2-28), adenoma or serrated lesions in 20% (95% CI -0-41) of cases.

CONCLUSION

The risk of appendiceal neoplasm in patients treated with interval appendectomy for complicated appendicitis is 11%; mucinous neoplasm is the most common histopathological type. Further studies should investigate this association in order to clarify the biological pathway and clinical implications.

Looking into digestive mixed neuroendocrine - nonneuroendocrine neoplasms: subtypes, prognosis, and predictive factors

Mixed neuroendocrine - nonneuroendocrine neoplasms (MiNENs) of the digestive system represent a challenge for both pathologists and clinicians. Their nomenclature has changed several times, and their diagnostic criteria, classification and clinical behaviour have been matter of debate over the years. Although several attempts have been made to elucidate the pathogenesis and biology of MiNENs, some issues remain open. This review will provide: a historical background that helps in understanding the evolution of the concept and nomenclature of mixed neoplasms; a revision of the knowledge on this topic, including molecular aspects, to give the reader a comprehensive and practical overview on this challenging field of pathology; a focus on the diagnostic criteria and on the determination of prognostic and predictive factors; and a description of the different tumour types in the different sites of origin.

Clinical implications of mismatch repair deficiency screening in patients with mixed neuroendocrine non-neuroendocrine neoplasms (MiNEN)

INTRODUCTION

Mixed neuroendocrine non-neuroendocrine neoplasms (MiNEN) are rare tumors, mainly encountered in the gastroenteropancreatic tract. Based on the limited available data, MiNEN is usually a highly aggressive neoplasm combining a high-grade neuroendocrine and a non-neuroendocrine component, associated with a poor prognostic outlook. Deficient DNA mismatch repair (MMR) results in microsatellite instability, which is a useful screening marker for identifying patients with Lynch syndrome and a prognostic factor for chemotherapeutic interventions. Little information on MMR status in MiNEN is available in published studies. Therefore, the purpose of this study was to explore the status and putative role of MMR on MiNEN.

METHODS

We investigated the MMR status in 44 cases and characterized their clinicopathological features and prognoses. Immunohistochemistry was performed for four mismatch repair proteins (MLH1, MSH2, MSH6, and PMS2).

RESULTS

Mean age at diagnosis was 61 years, and 75% of the patients were male. Lymph node metastases were observed in 14 (35.9%) patients. The most common tumor localizations were gastric (28 patients, 63.6%). Lack of immunohistochemical expression of MMR proteins was shown in 38.6% of cases. The common deletion rates of one or more proteins were 29.4% (5/17) for MLH1/PMS2 and 23.5% (4/17) for MLH1. Correlation between clinicopathological parameters showed that MMR deficiency was significantly associated with early TNM stage and better prognoses in patients with MiNEN.

CONCLUSION

MiNENs showed frequent losses of MMR protein expression, which contributes to the knowledge of the pathological and clinical aspects of MiNEN tumors.

Survival Profile and Prognostic Factors for Appendiceal Mixed Neuroendocrine Non-neuroendocrine Neoplasms: A SEER Population-Based Study

Introduction

Mixed neuroendocrine non-neuroendocrine neoplasm (MiNEN) is a rare form of neuroendocrine neoplasms (NENs). The purpose of this study was to investigate the characteristics and survival profile of appendiceal MiNENs, with a view of providing robust clinical features of this rare disease.

Methods

Patients were selected from the Surveillance, Epidemiology, and End Results database (2004–2016). The prognosis of MiNEN (n = 315) was compared with other histological subtypes including neuroendocrine tumor (NETs) (n = 1734), neuroendocrine carcinoma (NECs) (n = 375), goblet cell carcinoid (GCC) (n = 968), signet ring cell carcinoma (n = 463), mucinous adenocarcinoma (MAC) (n = 2355), and non-mucinous adenocarcinoma (NMAC) (n = 1187) in the appendix. Age-adjusted incidence was calculated using Joinpoint regression. The Cox proportional hazards model and the Fine–Gray competing risk model were used to perform overall survival (OS) and cancer-specific mortality (CSM) analyses, respectively.

Results

The age-adjusted incidence of MiNENs increased from 0.01/100,000 person-years in 2004 to 0.07/100,000 person-years in 2016. The 3-, 5-, and 10-year OS rates for MiNENs were 69.5, 57.4, and 43.7%, respectively, and the corresponding CSM rates were 23.1, 36.4, and 45.1%, respectively. Multivariate analysis revealed that the prognosis of MiNENs was worse than that of NETs, NECs, GCC, and MAC but better than that of NMAC and signet ring cell carcinoma. Tumor extension was the only independent factor influencing the prognosis of MiNENs, but tumor size, grade, and surgical approaches were not. Moreover, when compared with local excision or appendectomy, extensive surgery such as hemicolectomy or colectomy did not prolong the survival of individuals with MiNENs.

Conclusion

MiNEN is a rare but aggressive tumor with a poor prognosis differing from NENs, GCC and adenocarcinomas. To improve the prognosis of the disease, early diagnosis and comprehensive evaluation are necessary.

Mixed Adenoneuroendocrine Carcinoma (MANEC) of the Gallbladder: A Systematic Review of Outcomes Following Surgical Management

BACKGROUND/AIM

Mixed adenoneuroendocrine carcinomas (MANEC) are uncommon tumors exhibiting both adenocarcinomatous and neuroendocrine differentiation. They most commonly arise in the colon, appendix, rectum or stomach, however, a limited number of MANECs have been reported to originate in the gallbladder (gMANEC). The aim of our systematic review was to accumulate the existing data on gMANEC with special attention to the clinicopathological characteristics, surgical approach, recurrence and survival rates of patients diagnosed with this rare malignancy.

MATERIALS AND METHODS

A comprehensive search of the literature was undertaken.

RESULTS

A total of 15 studies (14 case reports and 1 case series), which comprised 19 patients who successfully underwent surgical treatment for gMANEC were included in our systematic review. During a median follow-up of 8 months (range=2-48 months) the overall survival was 87% and the recurrence rate was 21%.

CONCLUSION

Achievement of complete surgical resection is the mainstay of the therapeutic management. Additionally, the stage of the disease and the histopathological mapping of these tumors affect decision-making for adjuvant chemotherapy and seem to define the prognostic course of each patient.

Gastrointestinal mixed adenoneuroendocrine carcinoma: a population level analysis of epidemiological trends

Background

The rise in incidence and mortality of gastrointestinal mixed adenoneuroendocrine carcinoma (MANEC) has not been well focused. The aim of our study was to examine epidemiological trends in incidence and incidence-based (IB) mortality of gastrointestinal MANEC at a population level.

Methods

The incidence and IB mortality of gastrointestinal MANEC as well as data on affected patients from 2000 to 2016 were obtained from the Surveillance, Epidemiology, and End Results database. Trends in incidence and IB mortality were assessed using Joinpoint regression. The Kaplan–Meier method and log-rank test were used for survival analysis. Cox proportional hazards regression was used to identify independent predictors of mortality.

Results

581 patients diagnosed with gastrointestinal MANEC were enrolled. Gastrointestinal MANEC incidence was 0.23 cases per 1,000,000 individuals in 2000 and 1.16 cases per 1,000,000 individuals in 2016, with an annual percent change (APC) of 8.0% (95% CI 5.7–10.3%, P < 0.05). IB mortality also showed a sustained increase (APC 12.9%, 95% CI 9.0–16.8%, P < 0.05). In Cox regression analysis, age at diagnosis, tumor grade and stage, lymph node metastasis, surgery, and tumor size were independently associated with mortality. Median survival was 75 months (95% CI 60–128 months). Median survival of appendiceal MANEC was significantly longer than that of cecal MANEC (115 vs. 31 months; P < 0.001).

Conclusions

We found a sustained and rapid increase both in incidence and IB mortality of gastrointestinal MANEC, manifesting that there has been no significant improvement in patient outcomes, nor progress in prevention and treatment. Additional resources should be devoted to gastrointestinal MANEC research.

Mixed Neuroendocrine Non-Neuroendocrine Neoplasms: A Systematic Review of a Controversial and Underestimated Diagnosis

Mixed neuroendocrine non-neuroendocrine neoplasms (MiNENs) represent a rare diagnosis of the gastro-entero-pancreatic tract. Evidence from the current literature regarding their epidemiology, biology, and management is of variable quality and conflicting. Based on available data, the MiNEN has an aggressive biological behaviour, mostly driven by its (often high-grade) neuroendocrine component, and a dismal prognosis. In most cases, the non-neuroendocrine component is of adenocarcinoma histology. Due to limitations in diagnostic methods and poor awareness within the scientific community, the incidence of MiNENs may be underestimated. In the absence of data from clinical trials, MiNENs are commonly treated according to the standard of care for pure neuroendocrine carcinomas or adenocarcinomas from the same sites of origin, based on the assumption of a biological similarity to their pure counterparts. However, little is known about the molecular aberrations of MiNENs, and their pathogenesis remains controversial; molecular/genetic studies conducted so far point towards a common monoclonal origin of the two components. In addition, mutations in tumour-associated genes, including TP53, BRAF, and KRAS, and microsatellite instability have emerged as potential drivers of MiNENs. This systematic review (91 full manuscripts or abstracts in English language) summarises the current reported literature on clinical, pathological, survival, and molecular/genetic data on MiNENs.

Do neuroendocrine carcinomas and mixed neuroendocrine-non-neuroendocrine neoplasm of the gastrointestinal tract have the same prognosis? A SEER database analysis of 12,878 cases

BACKGROUND

Neuroendocrine carcinomas (NECs) and mixed neuroendocrine-non-neuroendocrine neoplasm (MiNEN) in the gastrointestinal (GI) tract are both rare and malignant; however, it is unclear whether their prognosis is the same.

METHODS

In this cross-sectional study, a total of 12,878 patients with NEC or MiNEN in the GI tract were reviewed retrospectively by searching the Surveillance, Epidemiology, and End Results (SEER) program database. Next, we compared the characteristics and survival between patients with NEC or MiNEN and further analyzed the prognostic factors for the patients.

RESULTS

The data showed that patients with MiNEN had a worse prognosis as compared with patients with pure NEC in the small intestine (SI) and appendix, whereas there was no significant survival difference between NEC and MiNEN in the other parts of the GI system. On the whole, age ⩾55 years (p < 0.0001), male (p = 0.002), being diagnosed at TNM Stage II-IV (p < 0.0001) or not receiving surgical treatment (p < 0.0001) were the independent negative prognostic factors for NEC patients, whereas age ⩾55 years (p = 0.003), being diagnosed at TNM Stage III-IV (p < 0.001) or not receiving surgical treatment (p < 0.001) were identified as the independent negative prognostic factors for the MiNEN patients. Furthermore, when NECs or MiNENs were classified based on the primary tumor site, the results showed that the prognostic factors for NEC and MiNEN varied between the tumor sites.

CONCLUSION

The prognostic differences between NECs and MiNENs in the GI tract are heterogeneous and site-related. Patients with appendiceal or SI MiNEN have a poorer prognosis than patients with pure appendiceal or SI NEC. Therefore, we should pay more attention to patients with MiNEN in the SI and appendix and monitor them more closely.

Management of Gastrointestinal Neuroendocrine Tumors

Neuroendocrine neoplasms (NENs) are derived from neuroendocrine cell system and can have benign or malignant characteristics. They are rare tumors, but have been increasing in incidence over the past 40 years. Patients with NENs may develop symptoms due to primary tumor invasion, metastasis, or from secretion of hormonally active tumor substances. Multiple imaging modalities are used for diagnosis and staging, including specialty scans such as ¹¹¹In pentetreotide (Octreoscan) and ⁶⁸Gallium-DOTATATE, along with endoscopy, endoscopic ultrasound, and biochemical marker testing. Treatment involves both surgical approach, for both primary and metastatic lesions, as well as medical management for symptom management and disease progression. This article will review the current clinical knowledge regarding the diagnosis, treatment, and prognosis of these fascinating neoplasms and the associated hormonal syndromes.

Retrospective study on mixed neuroendocrine non-neuroendocrine neoplasms from five European centres

BACKGROUND

Mixed neuroendocrine non-neuroendocrine neoplasm (MiNEN) is a rare diagnosis, mainly encountered in the gastro-entero-pancreatic tract. There is limited knowledge of its epidemiology, prognosis and biology, and the best management for affected patients is still to be defined.

AIM

To investigate clinical-pathological characteristics, treatment modalities and survival outcomes of a retrospective cohort of patients with a diagnosis of MiNEN.

METHODS

Consecutive patients with a histologically proven diagnosis of MiNEN were identified at 5 European centres. Patient data were retrospectively collected from medical records. Pathological samples were reviewed to ascertain compliance with the 2017 World Health Organisation definition of MiNEN. Tumour responses to systemic treatment were assessed according to the Response Evaluation Criteria in Solid Tumours 1.1. Kaplan-Meier analysis was applied to estimate survival outcomes. Associations between clinical-pathological characteristics and survival outcomes were explored using Log-rank test for equality of survivors functions (univariate) and Cox-regression analysis (multivariable).

RESULTS

Sixty-nine consecutive patients identified; Median age at diagnosis: 64 years. Males: 63.8%. Localised disease (curable): 53.6%. Commonest sites of origin: colon-rectum (43.5%) and oesophagus/oesophagogastric junction (15.9%). The neuroendocrine component was; predominant in 58.6%, poorly differentiated in 86.3%, and large cell in 81.25%, of cases analysed. Most distant metastases analysed (73.4%) were occupied only by a poorly differentiated neuroendocrine component. Ninety-four percent of patients with localised disease underwent curative surgery; 53% also received perioperative treatment, most often in line with protocols for adenocarcinomas from the same sites of origin. Chemotherapy was offered to most patients (68.1%) with advanced disease, and followed protocols for pure neuroendocrine carcinomas or adenocarcinomas in equal proportion. In localised cases, median recurrence free survival (RFS); 14.0 months (95%CI: 9.2-24.4), and median overall survival (OS): 28.6 months (95%CI: 18.3-41.1). On univariate analysis, receipt of perioperative treatment (vs surgery alone) did not improve RFS (P = 0.375), or OS (P = 0.240). In advanced cases, median progression free survival (PFS); 5.6 months (95%CI: 4.4-7.4), and median OS; 9.0 months (95%CI: 5.2-13.4). On univariate analysis, receipt of palliative active treatment (vs best supportive care) prolonged PFS and OS (both, P < 0.001).

CONCLUSION

MiNEN is most commonly driven by a poorly differentiated neuroendocrine component, and has poor prognosis. Advances in its biological understanding are needed to identify effective treatments and improve patient outcomes.

Lymphovascular Invasion Is Associated with Lymph Node Involvement in Small Appendiceal Neuroendocrine Tumors

BACKGROUND

Appendiceal neuroendocrine tumors (NETs) are incidentally found in up to 1% of appendectomy specimens. The association of lymphovascular invasion (LVI) with risk of regional lymph node involvement is unclear.

METHODS

From the National Cancer Database, 2004-2015, this study identified patients who had tumors 2 cm or smaller with one or more lymph nodes (LNs) pathologically evaluated. The histology was defined as typical, goblet cell, or composite NETs. Patient demographics, tumor characteristics, and treatment variables were analyzed.

RESULTS

The histologies for the 1767 identified patients were typical (n = 921, 52.1%), goblet cell (n = 556, 31.5%), and composite (n = 290, 16.4%). The tumor grades were low (70.4%), moderate (18.6%), and high (11%). The overall LN positivity was 17%. Of 1052 tumors evaluated, 215 (20.4%) had LVI. Overall survival decreased with node involvement (mean 84 vs. 124 months; p < 0.0001, log-rank). In the multivariate logistic regression analysis, LVI was independently associated with node involvement [odds ratio (OR) 5.0; p < 0.0001] after adjustment for patient age and tumor histologic subtype, size, and grade. In the subset analysis of typical NETs, tumor size of 1-2 cm (ref. < 1 cm; OR 5.5; p < 0.001) and presence of LVI (ref. absence of LVI; OR 4.8; p < 0.0001) were the only factors independently associated with LN involvement.

CONCLUSIONS

Node involvement is associated with worse overall survival in appendiceal NETs. The presence of LVI was strongly associated with lymph node involvement. An appendectomy specimen showing LVI should prompt strong consideration of colectomy with regional lymphadenectomy even for small, typical appendiceal NETs.

Mixed adenoendocrine carcinoma in the extrahepatic biliary tract: A case report and literature review

Neuroendocrine neoplasm (NEN) comprises a group of tumors that exhibit neuroendocrine phenotypes. NEN is subclassified into neuroendocrine tumor (NET), neuroendocrine carcinoma (NEC) and mixed adenoendocrine carcinoma (MANEC), based on histopathological parameters. NEN in the extrahepatic biliary tract (EHBT) is uncommon. Little is known about its clinicopathological features and prognostic indicators. The present study presented a case of MANEC in the distal common bile duct (CBD) and reviewed previous cases of NENs in the EHBT to characterize the clinical settings of this disease entity and to identify influencing factors of survival outcomes. A 64-year-old Chinese woman presented with abdominal pain and jaundice. Imaging studies demonstrated malignant stenosis in the distal CBD. Bile duct brush cytology revealed small clusters of atypical cells. Following an initial diagnosis of distal cholangiocarcinoma (CCA), the patient underwent pancreaticoduodenectomy. Histological analysis combined with immunohistochemical investigation of the resected specimen revealed a collision tumor that was composed of poorly differentiated adenocarcinoma and NEC. Each histological component accounted for >30% of the tumor. The definitive diagnosis was a MANEC in the distal CBD. Multiple intrahepatic and pulmonary metastases were observed postoperatively over 8 months. The patient succumbed to the disease 12 months after surgery. In conclusion, NEN occurs infrequently in the EHBT, with NET being the predominant type. NEN in the EHBT is extremely challenging to diagnose preoperatively due to its tendency to mimic CCA. Patients with NEN in the EHBT exhibited extremely distinct oncology outcomes according to pathological types. Additionally, old age (>60 years) and the presence of tumor recurrence were associated with decreased survival of patients with NEN.

Typical carcinoids, goblet cell carcinoids, mixed adenoneuroendocrine carcinomas, neuroendocrine carcinomas and adenocarcinomas of the appendix: a comparative analysis of survival profile and predictors

Background

Goblet cell carcinoids (GCC) and other atypical neuroendocrine tumors (NET) of the appendix as well as appendiceal adenocarcinoma are usually managed with the same algorithm as colon cancers. This study investigates clinicopathological features that are predictive of survival outcomes for appendiceal NET and adenocarcinoma. Survival profiles for the histologic subtypes of appendiceal NET and adenocarcinoma were compared.

Methods

A retrospective review of appendiceal NET and adenocarcinoma for patients who are 18 years and above in the SEER database from 2010 to 2014.

Results

Females outnumbered males in a 1.3 to 1 ratio in the NET subgroup and 1.1 to 1 ratio in the adenocarcinoma group. The mean age at diagnosis for all NET was 50.3±17 years while that of adenocarcinomas was 60.8±14.1 years. Within the NET subgroups, the mean ages for typical carcinoids (TC), GCC, NEC and MANEC were 42.9±17.3, 56.7±13.7, 45.6±17.4 and 59.7±12.8 years, respectively. Overall survival for adenocarcinoma was 86.3%, 73.5%, 65.7%, and 57.6% for 1-, 2-, 3- and 4-year OS, respectively. For NET, TC showed better survival profile with 1- and 4-year overall survival of 97.4% and 95.7%, respectively while MANEC had the worst survival outcome with 1- and 4-year OS of 88.6% and 62.2%, respectively. GCC had a better 1-year OS compared to NEC (95.5% versus 92.9%) but showed slightly worse 4-year OS (82% versus 84.8%). Age at diagnosis (HR 1.03), African-American race (HR 1.47) and stage IV disease (HR 9.58) were independent predictors of survival for appendiceal adenocarcinoma. For NET, advanced age at diagnosis, advanced disease stage and the African-American race were identified as negative independent predictors of survival.

Conclusions

While prior studies have suggested that atypical NET (GCC, NEC and MANEC) are more likely to present at more advanced stages, this study showed that most cases of GCC, MANEC and NEC were diagnosed at stages I and II. Appendiceal adenocarcinoma, on the other hand, presented mostly at stage IV. With respect to OS, atypical histologic subtypes of NET have worse outcome compared to TC. Although better OS was noted for GCC, NEC and MANEC when compared to adenocarcinoma, this benefit was lost in stage IV disease where adenocarcinoma recorded better 1- and 4-year OS. Prospective and randomized studies which provide granular details of treatment are needed to better define treatment algorithm for appendiceal NET.

Goblet Cell Carcinoid/Carcinoma: An Update

Goblet cell carcinoid (GCC) or goblet cell carcinoma is a unique mixed endocrine-exocrine neoplasm that is almost exclusively seen in the appendix. The hallmark of GCC is the concentric infiltration of the appendiceal wall by small tight clusters, nests or cords of tumor cells that exhibit a goblet cell morphology with a small compressed nucleus and conspicuous intracytoplasmic mucin. The coexistence of high-grade adenocarcinoma with GCC has been increasingly recognized as a common finding, which has been called adenocarcinoma ex GCC or mixed GCC-adenocarcinoma. A number of studies have shown that it is the high-grade adenocarcinomatous component that dictates the prognosis. Several histologic classification/grading systems have been proposed, which correlate with overall patient survival. Treatment options are primarily based on tumor stage and the presence or absence of a high-grade adenocarcinomatous component.

Appendiceal neoplasm risk associated with complicated acute appendicitis-a population based study

PURPOSE

Appendiceal tumors are rare, but high neoplasm rates have been reported at interval appendectomy after periappendicular abscess. Non-operative management of uncomplicated acute appendicitis has shown promising results. The data on appendiceal tumor incidence and presentation among acute appendicitis patients is limited, especially in patient cohorts differentiating between uncomplicated and complicated acute appendicitis. Objective was to assess appendiceal tumor incidence and tumor association to appendicitis in patients with uncomplicated and complicated acute appendicitis.

METHODS

This nationwide population-based registry study was conducted from 2007 to 2013. The Finnish Cancer Registry and the National Institute for Health Registry were used to combine data on all appendiceal tumors and acute appendicitis diagnosis with medical reports evaluated at eight study hospitals.

RESULTS

Altogether, 840 appendiceal tumors were identified, and out of these, 504 patient reports were reviewed, including 472 patients in this study. Tumor was diagnosed at appendectomy for suspected acute appendicitis in 276 patients (58%). In the whole study, histologically acute appendicitis and tumor were both present in 53% (n = 250), and out of these, 41% (n = 102) were complicated and 59% (n = 148) uncomplicated acute appendicitis. The associated tumor risk was significantly higher in complicated acute appendicitis compared with uncomplicated cases (3.24% vs. 0.87%, p < 0.001). Overall tumor prevalence among acute appendicitis patients was 1.24%.

CONCLUSIONS

Appendiceal tumor prevalence in acute appendicitis was low. Tumor risk was significantly higher in complicated acute appendicitis compared with uncomplicated acute appendicitis. The risk of missed appendiceal tumors related to antibiotic therapy of uncomplicated acute appendicitis is very low.

Multiregion Comprehensive Genomic Profiling of a Gastric Mixed Neuroendocrine-Nonneuroendocrine Neoplasm with Trilineage Differentiation

Mixed neuroendocrine-nonneuroendocrine neoplasms (MiNENs) are a group of rare tumors previously known as mixed adenoneuroendocrine carcinomas (MANECs). The neuroendocrine component is high-grade and may consist of small-cell carcinoma or large-cell neuroendocrine carcinoma. The nonneuroendocrine component may consist of adenocarcinoma or squamous cell carcinoma. We report a unique case of a MiNEN with trilineage differentiation: large-cell neuroendocrine carcinoma, squamous cell carcinoma, and adenocarcinoma. The reported patient presented with symptoms of an upper gastrointestinal bleed and was ultimately diagnosed with a MiNEN with trilineage differentiation. This is the first report of this exceedingly rare tumor type to include next-generation sequencing of the 3 separate tumor entities. In addition, we review the current literature and discuss the role of next-generation sequencing in classifying and treating MiNEN tumors.

Mixed adenoneuroendocrine carcinoma: A review of pathologic characteristics

Mixed adenoneuroendocrine carcinoma (MANEC) is a rare pathologic entity defined as a tumor exhibiting both adenocarcinoma and neuroendocrine carcinoma components. Though uncommon, these tumors show aggressive behavior and generally portend a poor prognosis. This study seeks to further define clinicopathological characteristics of MANEC to aid in accurate diagnosis and properly direct clinical management. Thirty-four confirmed MANECs were identified in our 25-year retrospective review of cases arising in the gastrointestinal tract. Various gross and microscopic variables were compared to overall survival. Tumors diagnosed at advanced stage (pT4), had a prominent mucinous component and lacked goblet cell clusters, which were all significantly associated with worse overall survival. This study supports previous findings and further elucidates clinicopathologic characteristics of MANEC.

Neuroendocrine, goblet cell and mixed adeno-neuroendocrine tumours of the appendix: updates, clinical applications and the future

Appendiceal neuroendocrine neoplasms are rare, clinically challenging tumours that are typically incidentally diagnosed, have a poorly understood biology and have controversy surrounding their management. Most are adequately treated with appendectomy, and although distant metastases are rare, the threat of disease dissemination remains and current guidelines possess poor accuracy in terms of selecting patients requiring more extensive surgery, i.e. oncological right-hemicolectomy. Areas covered: In this article, we discuss the presentation and diagnostic work-up of patients with appendiceal neuroendocrine neoplasms, and also examine the evidence base for existing management strategies. We highlight controversies within the management of these tumours, and anticipate avenues for further progress. Although no longer classified as neuroendocrine neoplasms, we also discuss two related forms of tumours with neuroendocrine features - goblet cell cancers and mixed adeno-neuroendocrine carcinomas. Expert commentary: Existing guidelines for the treatment of appendiceal neuroendocrine neoplasms are derived from a limited evidence base and are unable to accurately predict which patients require extensive attempts at surgical disease control. Future advances in the field of improved patient selection for more extensive surgery may be possible with multi-factorial tumour assessment integrating morphological and molecular analyses.