Clinical Considerations and Prognosis of Well-Differentiated Neuroendocrine Tumor Occurring Within a Renal Teratoma—A Case Series

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.

A Case Report of Carcinoid With Teratoma Arising From the Renal Hilum

Teratoma is a germ cell tumor composed of 2 or 3 germ cell layers, and it can occur in various parts of the human body. However, teratomas of the renal hilum are particularly rare, and those complicated by carcinoids are even more uncommon. Herein, we report the example of an asymptomatic 49-year-old woman in whom a tumor in the right renal hilum was unexpectedly discovered on imaging. Histological examination revealed a carcinoid tumor arising from a simple cyst composed of teratomatous tissue. Although the tumor was located in the renal hilum and touched the renal parenchyma, it appeared independent of the kidney and urinary tract. This report highlights the rare occurrence of teratomas with carcinoids and provides insights into their origins.

Primary Renal Well-Differentiated Neuroendocrine Tumors: Analyis of Six Cases from a Tertiary Care Center in North India with Review of Literature

Well-differentiated renal neuroendocrine tumors are rare tumors. As their biologic behavior is not fully known, there is a need to know more about these cases. We performed a retrospective chart review of all the cases diagnosed with renal neuroendocrine tumors from January 2016 to December 2020 (five years) in order to understand their clinical features, morphological characteristics and outcome. We included six cases with mean age of 46.2 years (4 males) in our study. All patients underwent radical nephrectomy. Histologically all showed tumor disposed in nests and trabeculae and majority of the tumors belonged to well-differentiated neuroendocrine tumor Grade 1 (WHO criteria of gastoroenteropancreatic neuroendocrine neoplasms). Lymph node metastasis was seen in two cases at the time of clinical presentation. All the tumors were diffusely positive for neuroendocrine tumor markers (synaptophysin, chromogranin, NSE, CD56). Follow-up data was available in all cases with an average follow-up of two years and neither has shown evidence of metastasis or relapse till last follow-up. Role of morphological patterns and immunohistochemical markers is highlighted with the importance of including Ki-67 index in grading them to better understand their outcome.

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.