Carcinoid tumors of the urinary tract and prostate

Prognostic factors and treatment impact on overall survival in patients with renal neuroendocrine tumour

Background

Renal neuroendocrine neoplasms (R-NEN) are exceptionally rare tumours characterized by high mortality rates.

Objective

The objective of this study is to analyse prognostic factors and treatment impact on overall survival in patients with R-NEN.

Design setting and participants

We identified all patients with R-NEN in the National Cancer Database (NCDB) from 2004 to 2019 and identified prognostic factors for improved survival.

Results and limitations

Of 542 R-NEN cases, 166 (31%) were neuroendocrine tumour grade 1 (NET-G1), 14 (3%) were neuroendocrine tumour grade 2 (NET-G2), 169 (31%) were neuroendocrine carcinoma (NEC-NOS), 18 (3%) were large cell neuroendocrine carcinoma (LC-NEC) and 175 (32%) were small cell neuroendocrine carcinoma (SC-NEC). Median overall survival for all patients in the study was 44.88 months (SE, 4.265; 95% CI, 27.57-62.19). Median overall survival was 7.89 months (SE 0.67; 95% CI, 6.58-9.20) for patients without surgical intervention and 136.61 months (SE 16.44; 95% CI, 104.38-168.84, p < 0.001) for patients who underwent surgery. Increased age (HR, 1.05; 95% CI, 1.03-1.06; p < 0.001), T4 stage disease (HR, 3.17; 95% CI, 1.96-5.1; p < 0.001), NEC-NOS histology (HR, 2.82; 95% CI, 1.64-4.86; p < 0.001), LC-NEC histology (HR, 2.73; 95% CI, 1.04-7.17; p = 0.041) and SC-NEC histology (HR, 5.17; 95% CI, 2.95-9.05; p < 0.001) were all positive predictors of worsening overall survival. The main limitation of the study is its retrospective design.

Conclusion

R-NEN is an aggressive tumour characterized by high mortality rates. Surgery continues to be the mainstay of treatment and has shown to provide a survival benefit for most patients.

Patient Summary

R-NEN is composed of several tumour histologies that differ based on their aggressiveness with NEC-NOS and SC-NEC being the most lethal. Surgery, predominantly through minimally invasive approaches, is the mainstay of treatment and has a clear survival benefit.

Primary Well-Differentiated Neuroendocrine Tumor/Carcinoid of the Prostate: Case Report and Review of Literature

Primary well-differentiated neuroendocrine tumor (WDNT)/carcinoid of the genitourinary tract is rare. Many WDNT reported in the prostate gland have been seen in close association with conventional prostatic adenocarcinoma and/or label for prostate-specific immunohistochemical markers and are best considered prostatic adenocarcinomas with "carcinoid-like" features. We present a case of primary WDNT/carcinoid incidentally detected in a 67-year-old man who underwent radical prostatectomy for Grade group 2 prostatic adenocarcinoma. Morphologically, the neuroendocrine (NE) lesion appeared distinct from the prostatic adenocarcinoma, labeled for NE markers, was negative for prostatic markers (NKX3.1, PSA, and ERG), and showed an overall low Ki-67 proliferation index (<1%). Follow-up was uneventful with no evidence of residual disease or metastasis.

Reporting Trends, Practices, and Resource Utilization in Neuroendocrine Tumors of the Prostate Gland: A Survey among Thirty-Nine Genitourinary Pathologists

Background. Neuroendocrine differentiation in the prostate gland ranges from clinically insignificant neuroendocrine differentiation detected with markers in an otherwise conventional prostatic adenocarcinoma to a lethal high-grade small/large cell neuroendocrine carcinoma. The concept of neuroendocrine differentiation in prostatic adenocarcinoma has gained considerable importance due to its prognostic and therapeutic ramifications and pathologists play a pivotal role in its recognition. However, its awareness, reporting, and resource utilization practice patterns among pathologists are largely unknown. Methods. Representative examples of different spectrums of neuroendocrine differentiation along with a detailed questionnaire were shared among 39 urologic pathologists using the survey monkey software. Participants were specifically questioned about the use and awareness of the 2016 WHO classification of neuroendocrine tumors of the prostate, understanding of the clinical significance of each entity, and use of different immunohistochemical (IHC) markers. De-identified respondent data were analyzed. Results. A vast majority (90%) of the participants utilize IHC markers to confirm the diagnosis of small cell neuroendocrine carcinoma. A majority (87%) of the respondents were in agreement regarding the utilization of type of IHC markers for small cell neuroendocrine carcinoma for which 85% of the pathologists agreed that determination of the site of origin of a high-grade neuroendocrine carcinoma is not critical, as these are treated similarly. In the setting of mixed carcinomas, 62% of respondents indicated that they provide quantification and grading of the acinar component. There were varied responses regarding the prognostic implication of focal neuroendocrine cells in an otherwise conventional acinar adenocarcinoma and for Paneth cell-like differentiation. The classification of large cell neuroendocrine carcinoma was highly varied, with only 38% agreement in the illustrated case. Finally, despite the recommendation not to perform neuroendocrine markers in the absence of morphologic evidence of neuroendocrine differentiation, 62% would routinely utilize IHC in the work-up of a Gleason score 5 + 5 = 10 acinar adenocarcinoma and its differentiation from high-grade neuroendocrine carcinoma. Conclusion. There is a disparity in the practice utilization patterns among the urologic pathologists with regard to diagnosing high-grade neuroendocrine carcinoma and in understanding the clinical significance of focal neuroendocrine cells in an otherwise conventional acinar adenocarcinoma and Paneth cell-like neuroendocrine differentiation. There seems to have a trend towards overutilization of IHC to determine neuroendocrine differentiation in the absence of neuroendocrine features on morphology. The survey results suggest a need for further refinement and development of standardized guidelines for the classification and reporting of neuroendocrine differentiation in the prostate gland.

Primary neuroendocrine neoplasms of the kidney: a case report and literature review

Primary kidney neuroendocrine tumors (NETs) are rare renal malignancies. However, detecting and monitoring neuroendocrine neoplasms remains challenging because of their nonspecific nature. We herein present a case involving a 53-year-old woman who experienced episodes of intermittent abdominal pain, dizziness, and nausea for a period of 5 days. Computed tomography urography revealed a small (approximately 19- × 16-mm) nodular shadow in the left kidney. The nodular shadow exhibited slightly lower density than the surrounding tissue as well as enhancement, with a portion protruding into the renal sinus region. Histological and immunohistochemical analyses of the biopsy specimen from the mass indicated a well-differentiated NET. After analysis of this case, we performed a literature review and herein discuss various techniques for imaging and pathological diagnosis of renal NETs. Additionally, we provide insights into the treatment options and prognosis for affected patients. By combining this case study with the existing published literature, we aim to offer a valuable reference for clinicians treatment patients diagnosed with renal NETs.

Urinary Neuroendocrine Neoplasms Treated in the "Modern Era": A Multicenter Retrospective Review

BACKGROUND

Primary urinary neuroendocrine neoplasms (U-NENs) are extremely rare thus optimal treatment is unknown. Grading and treatment are typically extrapolated from other primary sites. Since 2010, the clinical landscape for NENs has changed substantially. We performed a retrospective review of U-NENs to assess treatment patterns and oncologic outcomes of patients treated in the recent era of NEN therapy.

PATIENTS AND METHODS

A multicenter retrospective review of patients diagnosed after 2005 and alive after 2010. Time to treatment failure (TTF) was used to evaluate progression and toxicity for systemic therapy. Tumors were categorized as having either well-differentiated neuroendocrine tumor (WDNET) or poorly differentiated neuroendocrine carcinoma (PDNEC) histology.

RESULTS

A total of 134 patients from 6 centers were included in our analysis, including 94 (70%) bladder, 32 (24%) kidney, 2 (1.5%) urethra and 4 other urinary primaries (3.0%). Poorly-differentiated neuroendocrine carcinoma was more common in bladder (92%) than non-bladder tumors (8%). Median Ki-67 available in bladder primary was 90% (n = 24), kidney 10% (n = 23), ureter 95% (n = 1), urethra 54% (n = 2), and others 90% (n = 3). Patients received a median of 2 therapies (range 0-10). Median time to death was not reached in locoregional WDNETs versus 8.2 years (95% CI, 3.5-noncalculable) in metastatic WDNETs (predominantly renal primary). Median time to death was 3.6 years (95% CI, 2.2-9.2) in locoregional PDNECs versus 1 year (95% CI, 0.8-1.3) in metastatic PDNECs (predominantly bladder primary).

CONCLUSION

This is the most extensive series examining treatment patterns in patients with U-NENs in the recent era of NEN therapy. The apparent inferior survival for bladder NENs is likely due to the preponderance of PDNECs in this group. As predicted, treatments for U-NENs mirrored that of other more common NENs. In our retrospective cohort, we observed that patients with WD-UNETs treated with peptide receptor radionuclide therapy (PRRT) and everolimus suggested potential activity for disease control in WD-UNETs. Prospective studies are needed to assess the activity of new oncology drugs in UNENs.

Primary renal neuroendocrine neoplasms: A systematic literature review, report of four local cases, and original survival analysis of 63 patients from a national registry 2012-2018

Primary renal neuroendocrine neoplasms (NEN) are rare. We aimed to conduct a systematic review, present local cases, and analyse data from the England's National Cancer Registration and Analysis Service (NCRAS) to provide comprehensive evidence on clinical experience, incidence, and survival to better characterize these tumours. First, a systematic review using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) method; second, a synthesis of local cases; and, finally, a retrospective population-based cohort analysis of renal NEN recorded between 2012 and 2018 on NCRAS were performed. Kaplan-Meier estimator was used to calculate overall survival and Cox proportional hazard regression to identify prognostic factors. Systematic review identified 48 articles and the evidence was summarized and presented. We reported data from four local cases presenting with abdominal and back pain but without carcinoid syndrome. In population-based analysis, we identified 63 cases of renal NEN between 2012 and 2018 from the registry. Age-standardized incidence was 0.09-0.32 per million with a median age of 64 years (interquartile range = 48-72 years). Survival was worse in males and those aged 64 years and over. Five-year survival for renal neuroendocrine tumours (NET) was 69.8% (95% confidence interval = 66.6-72.7) and neuroendocrine carcinomas (NEC) was 38.4% (95% confidence interval = 34.6-42.0). No independent predictive factor was identified in the multivariable analyses. We have given a systematic review of evidence, published local experience, and reported incidence and survival of renal NEN in England for the first time. We have provided clinicians with evidence on diagnosis and proposed a treatment algorithm of theses rare tumours. The incidence and median age of presentation in England is similar to other published series. Renal NET has better survival than renal NEC as expected. A uniform classification system would reduce inconsistencies in reporting and standardize treatment decisions for this neoplasia.

Neuroendocrine Neoplasms of the Female Genitourinary Tract: A Comprehensive Overview

Simple Summary

Primary neuroendocrine neoplasms (NENs) are a rare, heterogeneous group of tumors that include well-differentiated neuroendocrine tumors, poorly differentiated neuroendocrine carcinoma, and paraganglioma. NENs in the urinary tract are observed in <0.05% of individuals, in whom the bladder is the most common site. In this review, we described the epidemiology, pathogenesis, imaging, staging, and management of the genitourinary NENs.

Abstract

Primary neuroendocrine neoplasms are a rare heterogeneous group of tumors that include well-differentiated neuroendocrine tumors, poorly differentiated neuroendocrine carcinoma, and paraganglioma. An extensive literature search was used to compile the data regarding epidemiology, pathogenesis, imaging features, and management of the urinary system NENs. We also included the updated staging of the NENs at various locations of the urinary system.

Neuroendocrine and Aggressive-Variant Prostate Cancer

In prostate cancer, neuroendocrine (NE) differentiation may rarely present de novo or more frequently arises following hormonal therapy in patients with castration-resistant prostate cancer (CRPC). Its distinct phenotype is characterized by an aggressive clinical course, lack of responsiveness to hormonal therapies and poor prognosis. Importantly, a subset of CRPC patients exhibits an aggressive-variant disease with very similar clinical and molecular characteristics to small-cell prostate cancer (SCPC) even though tumors do not have NE differentiation. This aggressive-variant prostate cancer (AVPC) also shares the sensitivity of SCPC to platinum-based chemotherapy albeit with short-lived clinical benefit. As optimal treatment strategies for AVPC remain elusive, currently ongoing research efforts aim to enhance our understanding of the biology of this disease entity and improve treatment outcomes for our patients. This review is an overview of our current knowledge on prostate cancer with NE differentiation and AVPC, with a focus on their clinical characteristics and management, including available as well as experimental therapeutic strategies.

Imaging of non-epithelial neoplasms of the prostate

The purpose of this article is to review the spectrum of rare non-epithelial tumors of the prostate. This focused article will help the readers to understand the imaging findings of such rare entities attributed to their clinicopathological features. Radiologists must be familiar with the spectrum of non-epithelial tumors of the prostate, which helps to suggest alternate diagnosis other than adenocarcinoma, when imaging features are atypical. This is important because these tumors have different management approaches and prognoses when compared to adenocarcinoma of the prostate.

Facing treatment of non-urothelial bladder cancers in the immunotherapy era

Non-urothelial Bladder Cancer (BC) and variants of urothelial carcinoma account for up to 25 % of all BCs. Given their heterogeneity, these entities are not well represented in clinical trials and treatment remains challenging. Checkpoint inhibitor therapy has shown a role in the treatment of urothelial BC. By contrast, robust evidence regarding its use in other histological types is lacking. We aimed to provide a comprehensive update of non-urothelial and variant urothelial BC, exploring the evidence for immune checkpoint inhibitor therapy. A detailed analysis of the literature was conducted regarding epidemiology, aetiology, diagnosis, prognosis, treatment and outcomes of these patients in the immunotherapy era. A growing body of evidence suggests that immune checkpoint inhibition might have a role to play in non-urothelial BC, similarly to what happened with urothelial carcinomas.

ASCL1-regulated DARPP-32 and t-DARPP stimulate small cell lung cancer growth and neuroendocrine tumour cell proliferation

Background

Small cell lung cancer (SCLC) is the most aggressive form of lung cancer, and new molecular insights are necessary for prognostic and therapeutic advances.

Methods

Dopamine and cAMP-regulated phosphoprotein, Mr 32000 (DARPP-32) and its N-terminally truncated splice variant, t-DARPP, were stably overexpressed or ablated in human DMS-53 and H1048 SCLC cells. Functional assays and immunoblotting were used to assess how DARPP-32 isoforms regulate SCLC cell growth, proliferation, and apoptosis. DARPP-32-modulated SCLC cells were orthotopically injected into the lungs of SCID mice to evaluate how DARPP-32 and t-DARPP regulate neuroendocrine tumour growth. Immunostaining for DARPP-32 proteins was performed in SCLC patient-derived specimens. Bioinformatics analysis and subsequent transcription assays were used to determine the mechanistic basis of DARPP-32-regulated SCLC growth.

Results

We demonstrate in mice that DARPP-32 and t-DARPP promote SCLC growth through increased Akt/Erk-mediated proliferation and anti-apoptotic signalling. DARPP-32 isoforms are overexpressed in SCLC patient-derived tumour tissue, but undetectable in physiologically normal lung. Achaete-scute homologue 1 (ASCL1) transcriptionally activates DARPP-32 isoforms in human SCLC cells.

Conclusions

We reveal new regulatory mechanisms of SCLC oncogenesis that suggest DARPP-32 isoforms may represent a negative prognostic indicator for SCLC and serve as a potential target for the development of new therapies.

Primary Neuroendocrine Carcinoma of Kidney: Report of a Rare Case

Primary neuroendocrine tumor (NET) of kidney is extremely rare, with <100 cases reported so far. The aim of the present case study is to discuss the clinical and pathological findings of renal NET and review of the available literature. We herein report the case of a 42-year-old female patient, who presented with pain abdomen and hematuria. Immunohistochemistry of her nephrectomy specimen was positive for chromogranin A and CD56 and negative for uroplakin II, P40, and CD10. KI index was 60%. Due to rarity of the tumor, there are no established guidelines available for its treatment. She was treated with combination chemotherapy of cisplatin and etoposide.

Natural History of Renal Neuroendocrine Neoplasms: A NET by Any Other Name?

Renal neuroendocrine neoplasms are rare, with descriptions of cases limited to individual reports and small series. The natural history of this group of neuroendocrine neoplasms is poorly understood. In this study, we queried the Surveillance, Epidemiology and End Results (SEER) database over a four-decade period where we identified 166 cases of primary renal neuroendocrine neoplasms. We observed a 5-year overall survival of 50%. On multivariate analysis, survival was influenced by stage, histology, and if surgery was performed. We observed that patients managed by operative management had a greater frequency of localized or regional stage disease as well as a greater frequency of neuroendocrine tumor, grade 1 histology; whereas those managed non-operatively tended to have distant disease and histologies of neuroendocrine carcinoma, NOS and small cell neuroendocrine carcinoma. This is the largest description of patients with renal neuroendocrine neoplasms. Increased survival was observed in patients with earlier stage and favorable histologies.

Non-urothelial carcinomas of the bladder

Non-urothelial carcinomas involving the bladder are uncommon and often diagnostically challenging. These carcinomas may show squamous, adenocarcinomatous or neuroendocrine features, with immunohistochemical stains aiding the diagnosis in only a subset of cases. The clinical history in non-urothelial bladder carcinomas is important, given that the differential diagnosis often includes secondary involvement of the bladder by direct extension or metastasis from carcinomas at other sites. This paper will review non-urothelial carcinomas in each of these three morphological categories, emphasising recent changes in diagnostic grouping and challenges in the histopathological diagnosis. Review of bladder cancers with squamous morphology will include discussion of conventional squamous cell carcinoma and verrucous carcinoma and their distinction from urothelial carcinoma with extensive squamous differentiation. Bladder carcinomas with adenocarcinomatous change will include primary bladder adenocarcinoma, urachal adenocarcinoma and tumours of Müllerian type. Finally, neuroendocrine neoplasms of the bladder, including well-differentiated neuroendocrine tumour and neuroendocrine carcinomas, will be discussed. Associated surface findings, risk factors and prognostic features will be described.

Clinical characteristics, treatment outcomes and potential novel therapeutic options for patients with neuroendocrine carcinoma of the prostate

Background

Neuroendocrine carcinomas of the prostate (NEPCs) are rare tumors with poor prognosis. While platinum and etoposide-based chemotherapy regimens (PE) are commonly applied in first-line for advanced disease, evidence for second-line therapy and beyond is very limited.

Methods

Retrospective analysis of all patients with NEPCs including mixed differentiation with adenocarcinoma component and well differentiated neuroendocrine tumors (NETs, carcinoids) at two high-volume oncological centers between 12/2000 and 11/2017.

Results

Of 46 identified patients 39.1 % had a prior diagnosis of prostatic adenocarcinoma only, 43.5 % had a mixed differentiation at NEPC diagnosis, 67.4 % developed visceral metastases, 10.9 % showed paraneoplastic syndromes. Overall survival (OS) from NEPC diagnosis was 15.5 months, and significantly shorter in patients with a prior prostatic adenocarcinoma (5.4 vs. 32.7 months, p=0.005). 34 patients received palliative first-line systemic therapy with a median progression-free survival (PFS) of 6.6 months, mostly PE. Overall response rate (ORR) for PE was 48.1 %. 19 patients received second-line therapy, mostly with poor responses. Active regimens were topotecan (1 PR, 3 PD), enzalutamide (1 SD), abiraterone (1 SD), FOLFIRI (1 SD), and ipilimumab+nivolumab (1 PR). One patient with prostatic carcinoid was sequentially treated with octreotide, peptide receptor radionuclide therapy and everolimus, and survived for over 9 years.

Conclusions

EP in first-line shows notable ORR, however limited PFS. For second-line therapy, topotecan, FOLFIRI, enzalutamide, abiraterone and immune checkpoint blockade are treatment options. Prostatic carcinoids can be treated in analogy to well differentiated gastrointestinal NETs.

Neuroendocrine tumors of the prostate

Neuroendocrine (NE) differentiation in tumors of the prostate or in the setting of prostate cancer (PCa) is rare. A survey of these lesions is presented, including usual PCa with focal NE marker-positive cells, Paneth cell-like change, prostatic 'carcinoid', high-grade NE carcinoma, as well as other tumors that do not fit neatly into these categories. The most significant clinical and pathologic features, emerging molecular evidence and the importance of differentiating NE tumors involving the prostate from secondary involvement are highlighted.

Nothing But NET: A Review of Neuroendocrine Tumors and Carcinomas

This review covers the diverse topic of neuroendocrine neoplasms (NENs), a relatively rare and heterogeneous tumor type, comprising ~2% of all malignancies, with a prevalence of <200,000 in the United States, which makes it an orphan disease (Basu et al., 2010).1 For functional purposes, NENs are divided into two groups on the basis of clinical behavior, histology, and proliferation rate: well differentiated (low grade to intermediate grade) neuroendocrine tumors and poorly differentiated (high grade) neuroendocrine carcinoma (Bosman et al., 2010)2; this histological categorization/dichotomization is highly clinically relevant with respect to impact on treatment and prognosis even though it is not absolute since a subset of tumors with a low-grade appearance behaves similarly to high-grade lesions. Given the relative dearth of evidenced-based literature about this orphan disease as a whole (Modlin et al., 2008),3 since the focus of most articles is on particular anatomic subtypes of NENs (i.e., gastroenteropancreatic or pulmonary), the purpose of this review is to summarize the presentation, pathophysiology, staging, current standard of care treatments, and active areas of current research.

Neuroendocrine neoplasms of the genitourinary tract in adults: cross-sectional imaging spectrum

Neuroendocrine (NE) neoplasms of the genitourinary (GU) tract in adults are rare tumors with distinct histopathology and variable biological behavior and imaging findings. They may be primary or metastatic in origin. The spectrum of primary GU tract NE neoplasms includes carcinoid, small cell carcinoma, large cell NE carcinoma, and paraganglioma. The tumors commonly show positivity to specific immunohistochemical markers and characteristic dense-core granules at the ultra-structural level. Although imaging findings are nonspecific and accurate differentiation from the more common malignancies of the individual organs is not possible, cross-sectional imaging modalities play an important role in the diagnosis, staging, and surveillance of these tumors. Somatostatin receptor scintigraphy (octreotide scan) may be useful in the detection and treatment of metastatic disease in select patients. Knowledge of the various NE tumors of the adult GU tract and familiarity with their pathological and imaging findings permit optimal patient management.

Neuroendocrine Tumors of the Urinary Bladder According to the 2016 World Health Organization Classification: Molecular and Clinical Characteristics

Neuroendocrine neoplasms of the urinary bladder are a rare type of tumor that account for a small percentage of urinary bladder neoplasms. These tumors of the urinary bladder range from well-differentiated neuroendocrine neoplasms (carcinoids) to the more aggressive subtypes such as small cell carcinoma. Despite the rarity of the neuroendocrine tumors of the bladder, there has been substantial investigation into the underlying genomic, molecular, and the cellular alterations within this group of neoplasms. Accordingly, these findings are increasingly incorporated into the understanding of clinical aspects of these neoplasms. In this review, we provide an overview of recent literature related to the 2016 World Health Organization Classification of Neuroendocrine Tumors of the Urinary Bladder. Particular emphasis is placed on molecular alterations and recently described gene expression. The neuroendocrine tumors of the urinary bladder are subdivided into four subtypes. Similar to their pulmonary and other extrapulmonary site counterparts, these have different degrees of neuroendocrine differentiation and morphological features. The clinical aspects of four subtypes of neuroendocrine tumor are discussed with emphasis of the most recent developments in diagnosis, treatment, and prognosis. An understanding of molecular basis of neuroendocrine tumors will provide a base of knowledge for future investigations into this group of unusual bladder neoplasms.

NEUROENDOCRINE RENAL CARCINOMA - THERAPEUTIC AND DIAGNOSTIC ISSUES

INTRODUCTION

Neuroendocrine renal carcinoma represents less than 1% of all primary neoplasia of the kidney. Most frequently poorly differentiated carcinoma is diagnosed in advanced stages and they have an aggressive evolution and limited survival rate. Neuroendocrine carcinomas that arise from the renal pelvis are frequently associated with squamous cell carcinoma or adenocarcinoma.

MATERIAL AND METHOD

We present the case of a female patient, known for 3 years before with an undefined retroperitoneal lymph node metastasis, being diagnosed at present with a left large cell neuroendocrine renal carcinoma, who initially had lymph node metastasis.

RESULTS

Until now, 118 cases of primary neuroendocrine renal carcinomas have been reported. A limited number of poorly differentiated neuroendocrine carcinomas have been reported.

DISCUSSION

Due to the clinical and biological findings, the aggressive evolution with early metastasis of lung and bone, the patient is included in the group of poorly differentiated carcinomas. In these cases, multimodal treatment is a gold standard. After surgical treatment and palliative chemotherapy with platinum salts, we obtained a partial remission of the disease and the control of symptoms.

CONCLUSIONS

Regarding large cell neuroendocrine carcinoma, the surgical treatment remains the treatment of choice. Chemotherapy can determine limited results, improve the quality of life and enhance the overall survival rate.

Carcinoid tumor associated with adjacent dysplastic columnar epithelium in the renal pelvis: A case report and literature review

Carcinoid tumors are well documented in the pulmonary and gastrointestinal systems, but very rare in the urinary tract, especially in the renal pelvis. We report on a 60-year-old female patient who presented with left flank pain and fever. Abdominal computed tomography demonstrated a heterogeneously enhancing mass in the left renal pelvis and a stone at the left proximal ureter. Multiple parenchymal lesions were also observed, which were identified as uneven caliectasis displaying air-fluid levels and renal parenchymal atrophy. The patient underwent simple nephro-ureterectomy. Macroscopically, a polypoid mass was observed in the renal pelvis. Microscopically, the tumor revealed acinar, tubular, and solid pattern and was composed of small, monotonous and hyperchromatic cells. Lining epithelia in renal pelvis and ureter revealed columnar epithelia with dysplastic change. The tumor cells were positive for chromogranin A, synaptophysin, CD56, and focally positive for cytokeratin. Immunohistochemical staining of synaptophysin and chromogranin A highlighted the neuroendocrine cells in the columnar epithelium. Ki-67 (1:50; MIB-1) labeling index was less than 1% in the area with highest uptake. We report here a case of carcinoid tumor of the renal pelvis that was associated with adjacent dysplastic columnar epithelium.

Primary renal carcinoid tumor: A radiologic review

Carcinoid tumor is the classic famous anonym of neuroendocrine neoplasms. Primary renal carcinoid tumors are extremely rare, first described by Resnick and colleagues in 1966, with fewer than a total of 100 cases reported in the literature. Thus, given the paucity of cases, the clinical and histological behavior is not well understood, impairing the ability to predict prognosis. Computed tomography and (occasionally) octreotide studies are used in the diagnosis and followup of these rare entites. A review of 85 cases in the literature shows that no distinctive imaging features differentiate them from other primary renal masses. The lesions tend to demonstrate a hypodense appearance and do not usually enhance in the arterial phases, but can occasionally calcify. Octreotide scans do not seem to help in the diagnosis; however, they are more commonly used in the postoperative followup. In addition, we report a new case of primary renal carcinoid in a horseshoe kidney.

A case of primary renal carcinoid tumor

Primary renal carcinoid tumors are extremely rare kidney lesions, with fewer than 100 reported cases previously. We describe a 75-year-old man with an incidentally detected cystic renal mass. Computed tomography showed a 3 cm tumor with a cystic component enhanced with contrast. No evidence of metastasis was detected. We treated the patient with radical nephrectomy. Pathological examinations revealed a cellular arrangement specific to carcinoid tumor and positive for chromogranin A, neural cell adhesion molecule, and somatostatin receptor type 2. The tumor cells had a mitotic count of 4 mitoses/10 high-power fields, and the level of the proliferation marker Ki-67 was 5%. The pathological diagnosis was renal neuroendocrine tumor grade 2. No local recurrence and no systemic metastasis were detected during the 18-month follow-up period. To our knowledge, this is the 6th case of renal neuroendocrine grade 2 tumor reported thus far.

Proposed morphologic classification of prostate cancer with neuroendocrine differentiation

On July 31, 2013, the Prostate Cancer Foundation assembled a working committee on the molecular biology and pathologic classification of neuroendocrine (NE) differentiation in prostate cancer. New clinical and molecular data emerging from prostate cancers treated by contemporary androgen deprivation therapies, as well as primary lesions, have highlighted the need for refinement of diagnostic terminology to encompass the full spectrum of NE differentiation. The classification system consists of: Usual prostate adenocarcinoma with NE differentiation; 2) Adenocarcinoma with Paneth cell NE differentiation; 3) Carcinoid tumor; 4) Small cell carcinoma; 5) Large cell NE carcinoma; and 5) Mixed NE carcinoma - acinar adenocarcinoma. The article also highlights "prostate carcinoma with overlapping features of small cell carcinoma and acinar adenocarcinoma" and "castrate-resistant prostate cancer with small cell cancer-like clinical presentation". It is envisioned that specific criteria associated with the refined diagnostic terminology will lead to clinically relevant pathologic diagnoses that will stimulate further clinical and molecular investigation and identification of appropriate targeted therapies.

Neuroendocrine tumors of the kidney: a single institution experience

BACKGROUND

Renal NETs, comprised of carcinoid tumors and small cell carcinomas, are a rare group of neoplasms. The rarity of these tumors pose a diagnostic and therapeutic challenge. Our purpose was to characterize the cases treated at a tertiary cancer center and to evaluate patient outcomes with the available treatment modalities.

PATIENTS AND METHODS

This was a retrospective study of patients with renal NETs seen at The University of Texas M.D. Anderson Cancer Center between January 1, 2001, and January 1, 2011. Patient and tumor data were analyzed using descriptive statistical methods.

RESULTS

Three cases of carcinoid tumors and 6 cases of small cell carcinoma were identified. The median age at diagnosis was 53 years for patients with carcinoid and 65 years for patients with small cell carcinoma. The most common presenting symptoms were back pain, flank pain, and hematuria. The morphological appearance of the tumor cells and their immunohistochemical reactivity for neuroendocrine markers and cytokeratin helped establish the diagnosis. Nephrectomy was the mainstay of treatment for carcinoid tumors, yielding good long-term results, even in the presence of metastases. Surgery and chemotherapy were used for small cell carcinoma of the kidney. The median overall survival for patients with small cell carcinoma of the kidney was 17.3 months.

CONCLUSION

Renal carcinoid tumors are indolent and are associated with prolonged survival, and small cell carcinomas of the kidney are aggressive tumors with relatively short overall survival. Although palliative in nature, cytotoxic chemotherapy is the mainstay of therapy and is best given before surgery.

Primary large cell neuroendocrine carcinoma of the renal pelvis: a case report

We report a case of primary large cell neuroendocrine carcinoma of the renal pelvis, diagnosed in a 79-year-old man. The abdominal computed tomography showed a solid, vegetant lesion in the left renal pelvis, conditioning marked hydronephrosis. The patient underwent radical nephroureterectomy. The histological examination showed a large cell neuroendocrine carcinoma associated with a high-grade urothelial carcinoma, with local invasion (pT3). Large cell renal neuroendocrine carcinomas are rare tumors with an aggressive course and a bad prognosis. At present, only five cases were reported in literature.

Primary carcinoid tumour of the kidney: a review of the literature

Context. Primary renal carcinoid tumours are rare. Their pathogenesis is unknown and the clinical presentation is similar to other renal tumours thus posing diagnostic dilemmas for clinicians. Objectives. To review the literature for case reports of primary renal carcinoids. Methods. Literature was extensively searched for case reports for primary renal carcinoids. Reports of metastatic carcinoids to the kidneys were excluded. Results. Approximately less than 90 cases of primary carcinoid tumours of the kidney have been reported in the literature. A total of 29 cases of primary renal carcinoids were reviewed. The mean age of presentation was 48 years (range 29–75) with both right kidney (48.3%) and left kidney (44.8%) being equally affected. 28.6% of the cases reviewed were diagnosed as an incidental finding. The mean followup time was 20 months with 73.1% of patients without evidence of disease after surgical treatment (radical or partial nephrectomy). Primary carcinoid tumours of the kidney are often well differentiated tumours. They are often misdiagnosed because of their rarity and similar presentation with other renal tumours. Conclusions. Primary carcinoid tumours of the kidney are rare tumours with an indolent course with frequent metastasis. Metastatic work up and followup is required in their management.

Primary renal carcinoid: treatment and prognosis

Primary carcinoid tumors of the kidney are very rare, malignant tumors consisting of neuroendocrine cells. The pathogenesis of renal carcinoid is unclear because neuroendocrine cells are not normally found in adult renal parenchyma. Electron microscopy, immunohistochemistry, octreotide scan, positron emission tomography along with conventional radiographic imaging techniques are used in diagnosis and follow-up. Presenting symptoms usually include flank pain and haematuria. Early stage disease is treated with surgery only. However, randomized trials are lacking because of the very low number of reported cases. Thus, the role of debulking surgery, chemotherapy, radiotherapy, octreotide and targeted therapy in the management of advanced disease remains an open question. In this article the clinicopathologic features and prognosis of this very rare disease along with treatment outcomes of the reported cases are reviewed. In addition, we report a new case of a metastatic primary renal atypical carcinoid tumor treated with octreotide therapy.

Primary neuroendocrine carcinoma of the kidney

BACKGROUND

The objective of the study was to report a rare case of primary neuroendocrine carcinoma of the right kidney in a 36 year old male.

METHODS

The patient was clinically assessed; CT and OctreoScan scintigraphy were performed and levels of 5-HIAA, vanillylmandelic acid and NSE were determined. The tumor and metastases were histologically and immunohistochemically examined.

RESULTS

The imaging methods showed a cystic tumor in the lower pole of the right kidney. Macroscopically, the entire tumor was sized 8x8x7 cm. Histologically, it was made up of ribbon-line or trabecular patterns of tumor cells. Occasional adenomatoid and cystic structures were present. The tumor cell nuclei were round or oval, with no irregularities and fine lumpy chromatin. The mitotic count was < 1 /10HPF and the proliferation marker Ki-67 was < 1 % of tumor cells. Immunohistochemically, the tumor cells were positive with antibodies against chromogranin A, synaptophysin, CD56 (focally), cytokeratins AE1-AE3 (focally), vimentin (most cells), glucagon (focally), and pancreatic polypeptide (PP; focally). Antibodies against serotonin, somatostatin, gastrin, vasoactive intestinal polypeptide (VIP) and calcitonin did not react with the tumor. The results of biochemical markers (5-HIAA, vanillylmandelic acid and NSE) did not correlate with development or treatment of the tumor.

CONCLUSIONS

Primary neuroendocrine carcinoma of the kidney was diagnosed both histologically and immunohistochemically. The patient was clinically investigated using CT and OctreoScan scintigraphy. Within two years from nephrectomy, metastases were found in the right humerus and retrocaval lymph nodes. The metastatic lesions were surgically removed. Currently, the patient's condition is good, with no tumor progression detected.

Carcinoid syndrome from small bowel endocrine carcinoma in the absence of hepatic metastasis

An 80-year-old male patient presented with abdominal pain, paroxysmal diaphoresis, diarrhoea and vomiting. CT scan revealed a small bowel endocrine carcinoma (or 'carcinoid' tumour), but the absence of hepatic disease. The lesion was excised 'en-bloc'. Intra-operatively, there was wide fluctuation in blood pressure associated with tumour manipulation, with hyper- and hypotension. Carcinoid syndrome usually occurs from gastrointestinal tumours when hepatic metastases occur, causing flushing, diarrhoea, bronchoconstriction and murmurs from cardiac valvular lesions. This patient did not have radiological evidence of hepatic metastasis, but the syndrome could still occur with midgut tumours via local invasion of the retroperitoneal circulation, or by action of substances other than serotonin that do not undergo hepatic metabolism.

Clinical utility of immunohistochemistry in the diagnoses of urinary bladder neoplasia

Urothelial carcinomas demonstrate diverse morphologic and immunologic features that frequently lead to diagnostic challenges. Recent advances have identified a number of immunohistochemical stains that, when used in the context of a panel, can be a valuable tool in properly classifying primary urothelial carcinoma and carcinomas secondarily involving the urinary bladder. In addition, new biomarkers prove helpful in the staging of bladder carcinoma. In this article, we review the clinical utility of immunohistochemistry in a series of diagnostic scenarios, including flat urothelial lesions with atypia, rare variants of urothelial carcinoma, primary adenocarcinoma versus secondary colorectal tumors, distinguishing prostate from urothelial carcinoma, and the utility of smoothelin in staging bladder carcinoma. Emphasis is placed on panels of commonly used biomarkers to establish diagnoses.

Carcinoid tumor of the verumontanum (colliculus seminalis) of the prostatic urethra with a coexisting prostatic adenocarcinoma: a case report

INTRODUCTION

Urethral carcinoid tumors are very rare tumors with only four cases described in the literature.

CASE PRESENTATION

We present the case of a 61-year-old man with a primary carcinoid tumor of the verumontanum (colliculis seminalis) portion of the prostatic urethra with a coexisting prostatic adenocarcinoma. In addition to whole mount hematoxylin and eosin staining, special immunoperoxidase staining specific for chromogranin A, neuron specific enolase, synaptophysin, pan-cytokeratin and PSA, and a special combined staining for racemase (alpha-methyl CoA) antigen and p63 antigen were performed. A review of the literature is included.A single focus of invasive prostatic adenocarcinoma was identified in the periphery of the mid-left, posterior quadrant of the prostate. Approximately 17 mm from this adenocarcinoma, within the verumontanum of the prostatic urethra, there was a 3 mm maximal dimension carcinoid tumor.

CONCLUSION

Based on different histological features and antigenic profiles, we concluded that the two tumors were distinct.

Renal carcinoid tumor: An immunohistochemical and molecular genetic study of four cases

Few genetic studies of renal carcinoid tumor have been conducted thus far. We performed immunohistochemical and genetic examinations on four renal carcinoid tumors. Histologically, the tumors consisted of neoplastic cells with round to oval nuclei. Various growth patterns such as tightly packed cords and trabeculae, ribbon-like, trabecular, sheet-like or solid growth were observed. Nuclear chromatin showed a coarse and granular pattern. Immunohistochemically, tumors were positive for chromogranin A and synaptophysin. In the fluorescence in situ hybridization study, three of four tumors revealed monosomy of chromosome 3 (D3Z1), but one tumor showed monosomy of chromosome 13 (D13S319/13q34). Using PCR amplification and fragment analysis of three microsatellite markers (D3S1300, D3S666 and D3S1768) of chromosome arm 3p, one tumor showed loss of heterozygosity at D3S1300 and D3S1768, one tumor was not informative and the analysis of two tumors failed due to low DNA quality. In three cases, the VHL gene status was tested. Two tumors showed wild-type, but the analysis of one tumor failed to provide adequate results. In conclusion, we suggest that the abnormality of chromosome 3 is involved in the pathogenesis of renal carcinoid tumor.

Invasive neuroendocrine tumor of the kidney: a case report

Neuroendocrine tumors (NETs) involve the genitourinary system in less than 1% of cases, with primary renal carcinoids comprising only 19% of reported genitourinary NETs (56 cases worldwide). We report a case of a renal NET presenting as a large renal mass with extensive local invasion, requiring definitive radical en bloc resection via a thoracoabdominal approach.

Synchronous primary carcinoid tumor and primary adenocarcinoma arising within mature cystic teratoma of horseshoe kidney: a unique case report and review of the literature

Background

Malignant transformation of mature cystic teratoma is a rare complication. While any of the constituent tissues of a teratoma has the potential to undergo malignant transformation, squamous cell carcinoma is the most commonly associated malignancy. Renal carcinoid tumors are rare and frequently associated with horseshoe kidney and renal teratoma. Renal teratoma rarely presents together with carcinoid tumor or adenocarcinoma. To the best of our knowledge, there has never been a report of renal teratoma coexisting with both carcinoid tumor and adenocarcinoma.

Methods

Here, we present a unique and first case of synchronous primary carcinoid tumor and moderately differentiated adenocarcinoma arising within mature cystic teratoma of horseshoe kidney in a 50-year-old female. Lumbar spine X-ray, done for her complaint of progressive chronic low back pain, accidentally found a large calcification overlying the lower pole of the right kidney. Further radiologic studies revealed horseshoe kidney and a large multiseptated cystic lesion immediately anterior to the right renal pelvis with central calcification and peripheral enhancement. She underwent right partial nephrectomy.

Results

Macroscopically, the encapsulated complex solid and multiloculated cystic tumor with large calcification, focal thickened walls and filled with yellow-tan gelatinous material. Microscopically, the tumor showed coexistent mature cystic teratoma, moderately differentiated adenocarcinoma and carcinoid tumor. Immunohistochemically, alpha-methylacyl-coenzyme A-racemase, calretinin, CD10 and thyroid transcription factor-1 were negative in all the three components of the tumor. The teratomatous cysts lined by ciliated epithelium showed strong staining for cytokeratin 7 and pancytokeratin, and those lined by colonic-like epithelium showed strong staining for CDX2, cytokeratin 20 and pancytokeratin, but both were negative for calretinin. Additionally, the teratomatous cyst wall showed strong staining for smooth muscle actin, and weak staining for carbonic anhydrase IX, CD99, chromogranin and synaptophysin. The adenocarcinoma component was strongly positive for cytokeratin 7 and pancytokeratin, weakly positive for synaptophysin and CD56, and negative for carbonic anhydrase IX, CD99, CDX2, chromogranin, cytokeratin 20 and smooth muscle actin. The carcinoid tumor component was strongly positive for CD56, chromogranin and synaptophysin, weakly positive for pancytokeratin, and negative for carbonic anhydrase IX, CD99, CDX2, cytokeratin 7, cytokeratin 20 and smooth muscle actin. She received no adjuvant therapy and is alive without evidence of disease six months after diagnosis and surgery.

Conclusion

This unique and first case herein presented with synchronous primary carcinoid tumor and primary adenocarcinoma arising within mature cystic teratoma of horseshoe kidney emphasizes the need for thorough sectioning and entire submission for histologic evaluation of mature cystic teratomas, in order to avoid missing multiple additional histogenetically distinct neoplasms.

Histological variants of urothelial carcinoma: diagnostic, therapeutic and prognostic implications

It is well established that invasive urothelial carcinoma, involving the urinary bladder and renal pelvis, has marked propensity for divergent differentiation. In recent years, several 'variant' morphologies have been described and most have been recognized in the 2004 World Health Organization Classification. These histological variants of urothelial carcinoma have clinical significance at various levels, including diagnostic, that is, awareness of the morphological variant is essential in order to avoid diagnostic misinterpretations; prognostic for patient risk stratification; and therapeutic, where a diagnostic assignment of a particular variant may be associated with the administration of a therapy distinctive from that used in conventional invasive urothelial carcinoma. The diagnoses of micropapillary urothelial carcinoma, small-cell carcinoma, lymphoepithelioma-like carcinoma and sarcomatoid carcinoma are prime examples where treatment protocols may be different than the usual muscle-invasive bladder cancer. This review discusses the variants of urothelial carcinoma, outlining for each the diagnostic features, differential diagnostic considerations and the clinical significance.

Neuroendocrine tumours of the urinary system and male genital organs: clinical significance

Two basic types of neuroendocrine (NE) tumours with diverse clinicopathological features and outcome are identified in the urinary system and male genital organs: carcinoid tumour and neuroendocrine carcinoma. Carcinoid, a rare tumour, occurs in the kidney, bladder, prostate and testis. It is morphologically, histochemically, immunohistochemically and ultrastructurally similar to its counterpart in other organs, such as lung or gastrointestinal tract. Metastases can be detected at the initial evaluation, although they have been reported up to several years after removal, emphasizing the need for a long-term follow-up. NE carcinoma occurs in the kidney, bladder and prostate, and includes small cell carcinoma (SCC) and large cell NE carcinoma (LCNEC), the latter being exceedingly rare. Both show the morphology and immunophenotype of NE carcinoma originating in other organs. Although the occurrence is rare, it is highly aggressive.

Development of carcinoid tumour in hormonally treated adenocarcinoma of the prostate

We present the case of an 81-yr-old man with a prostatic adenocarcinoma and a metastatic carcinoid. Simultaneous occurrence of hormonally treated adenocarcinoma of the prostate and a carcinoid has been described before. The pathogenesis of this coincidence is largely unclear; however, androgen deprivation therapy might play a key role in neuroendocrine differentiation of adenocarcinoma cells. Early recognition of the carcinoid syndrome is crucial, as surgical cure is not possible after metastasis. We provide a brief review of recent literature.

Unusual clinical and pathological presentation of a neuroendocrine tumor in a patient with multiple endocrine neoplasia type 1

Neuroendocrine tumors develop in various organs in patients with multiple endocrine neoplasia type 1 (MEN1). Among those, tumors developed in upper gastrointestinal tract, thymus and bronchus have historically been called "carcinoid tumor". Occurrence of "carcinoid tumor" in other region is very rare and molecular pathogenesis of such tumors is unknown. We have experienced a patient with MEN1 who have developed an "ectopic" retroperitoneal neuroendocrine tumor. Genetic analysis of the MEN1 gene in tumor cells revealed a somatic mutation in exon 9 as well as a germline mutation in exon 10. Allele-specific amplification followed by sequence analysis revealed these two mutations exist on the different allele, indicating both alleles are functionally inactivated. Immunohistochemical staining with an anti-menin antibody revealed that wild-type menin is not expressed in tumor cells. Expression of p27(Kip1) protein is not observed in tumor cells, either. These results confirmed the inactivation of the MEN1 gene as a genetic cause of an ectopically developed neuroendocrine tumor in a patient with MEN1.

Neuroendocrine tumor epidemiology: contrasting Norway and North America

BACKGROUND

The National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) program has proven to be a significant resource in US neuroendocrine tumor (NET) epidemiology. Norway also holds a robust and detailed cancer registry: the Norwegian Registry of Cancer (NRC).

METHODS

SEER NET data were compared with corresponding NRC data in the time period 1993 to 2004 to determine whether there are differences in NET epidemiology between Norway and the United States.

RESULTS

The SEER and NRC reported 17,312 and 2030 NETs, respectively. The overall Caucasian SEER NET incidence was 4.44, compared with 3.24 in the NRC. In the SEER white subset, bronchopulmonary NETs were the most common (incidence = 1.42; 32% of all NETs), compared with small intestinal NETs in the NRC (0.81; 26%). A marked increase in SEER NET incidence (37%-40%) was observed in the period 2000 to 2004, compared with 1993 to 1997; an even more pronounced increase (72%) was seen in the NRC. African Americans exhibited a remarkably high overall NET incidence of 6.50; furthermore, among African Americans, rectal NETs were most common (1.65; 27%). Small intestinal NET incidence was approximately 30% higher in men compared with women in all populations. The highest 5-year survival rates were for rectal NETs (74%-88%) in both databases, whereas prostatic NETs had the worst outcome (0%-23%). At diagnosis, NETs were localized in 27% to 46% of patients.

CONCLUSIONS

NET incidence in the US Caucasian population and in Norway is similar, but considerably higher ( approximately 50%) among African Americans. NETs have been regarded as indolent tumors; however, the 5-year survival is only approximately 55%.

Well-differentiated endocrine carcinoma of the renal pelvis: report of a case with sustained objective response to octreotide

Endocrine tumors of the upper urogenital tract are extremely rare. We report the case of a patient with a primary well-differentiated endocrine carcinoma of the renal pelvis metastatic to the liver, in whom an objective response was obtained under octreotide treatment. A 36-year-old woman without symptoms was admitted for exploration of a solid nodule in the right kidney. A right nephrectomy was performed. The histological examination of the surgical specimen diagnosed a primary well-differentiated endocrine tumor of the renal pelvis. Tumor cells strongly expressed synaptophysin and were focally positive for chromogranin A; they displayed faint reactivity for PSAP. Three months later, multiple liver metastases, proved by biopsy, were diagnosed. After two lines of chemotherapy, octreotide treatment was initiated because of persistent high activity at scintigraphic examination. A marked decrease in tumor volume and in chromogranin A serum levels was obtained. Two years later, there was no further progression. The patient was treated with octreotide. Our report points out the unusual immunophenotypic features which may be encountered in well-differentiated endocrine carcinoma of the upper urogenital tract and the potential interest in somatostatin analogues in the treatment of metastatic cases.

Risk factors associated with neuroendocrine tumors: A U.S.-based case-control study

Carcinoids are rare neuroendocrine tumors (NETs); however, their incidence has significantly increased in the United States over the past 30 years. Little is known about the epidemiology of these cancers and their associated risk factors. We evaluated the independent effects of multiple risk factors associated with NETs arising at 5 disease sites (small intestine, stomach, lung, pancreas and rectum). We conducted a retrospective, hospital-based, case-control study involving 740 patients with histologically confirmed NETs and 924 healthy controls. Information on different risk factors was collected, and unconditional logistic regression analysis was used to determine adjusted odds ratios (AORs) and 95% confidence interval (CI) by the maximum-likelihood method. Smoking and alcohol consumption were not associated with NETs development in either men or women. However, a family history of cancer was a significant risk factor for all NETs. A long-term history of diabetes mellitus was a significant risk factor for gastric NETs (AOR = 5.6; 95% CI, 2.1-14.5), particularly in women (AOR = 8.4; 95% CI, 1.9-38.1). Diabetes modified the risk among women with a positive family history of cancer for the development of gastric NETs (AOR = 52.2; 95% CI, 5.5-491.5). Our results suggest that the risk of NETs may mostly explained by genetic factors. The increased risk of gastric NETs in women with both diabetes and a positive family history of cancer suggest that women may have a greater genetic susceptibility to NETs than men.