Five New Cases of Primary Renal Carcinoid Tumor: Case Reports and Literature Review

Atypical carcinoid of the primary kidney with retroperitoneal metastasis 15 years later: A case report and literature review

Primary renal neuroendocrine tumors (NETs) are extremely rare among renal malignancies. According to pathological manifestations, carcinoid can be divided into four types: typical carcinoid, atypical carcinoid, large cell and small cell neuroendocrine carcinoma. Primary or secondary retroperitoneal carcinoid is even rarer than renal carcinoid. This article reports a patient with renal carcinoid complicated with retroperitoneal metastasis, who developed retroperitoneal metastasis 15 years after radical nephrectomy. Through the analysis of this case and the combination of the existing published literature, it is aimed to provide valuable references for clinicians in treating patients with renal carcinoid or with metastasis.

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.

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.

Renal Neuroendocrine Tumor: A Case Report with Evaluation of Grading Criteria and Relationship with Carbonic Anhydrase 9 Immunoreactivity

Neuroendocrine tumors (NETs) are only exceptionally primary to the kidney. At present, scant information is known regarding the behavior and prognosis of renal NETs, especially according to the assessment of grading parameters used for NETs originating from other more commonplace sites such as the pancreas and lungs. There are only rare reports of grade assessment in renal NETs, with most of these reports relying upon now antiquated World Health Organization gastroenteropancreatic and lung/thymus criteria. As an additional prognostic factor, positive CA9 staining in NETs may correlate with elevated grade, stage and risk of metastasis while serving as a potential target of chemotherapy and immunotherapy and indicator of Von Hippel-Lindau Syndrome. Rarer still are descriptions of renal NETs presenting with renal cell carcinoma in the ipsilateral or contralateral kidney. Thus, we present a patient with a primary renal NET of the right kidney with regional lymphovascular invasion and distant metastasis with an emphasis on grading criteria concordant with the World Health Organization 2022 gastroenteropancreatic and lung/thymus systems. In addition, we discuss unusual staining for CA9 in the patient's tumor and a concomitant left kidney clear cell renal cell carcinoma that may act as a clinicopathologic mimic of Von Hippel-Lindau Syndrome.

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.

Well‑differentiated neuroendocrine tumor of the right kidney: A case report

Neuroendocrine tumors (NETs) are tumors originating from neuroendocrine cells and peptidergic neurons. Primary renal well-differentiated NETs (WDNETs) are rare and only sporadic cases have been reported worldwide. In November 2021, a 45-year-old female patient was admitted to The Affiliated Hospital of Zunyi Medical University (Zunyi, China) with right-sided lumbago. Abdominal computed tomography revealed a 44×34×70-mm mass in the right kidney. Following a complete examination, a laparoscopic partial nephrectomy of the right kidney was performed under general anesthesia. The postoperative pathology indicated a well-differentiated NET of the right kidney. There was no tumor recurrence or metastasis during the 1-year follow-up period. WDNETs are rare, their clinical and imaging findings are not specific, and their diagnosis depends on immunohistochemical analysis. The degree of malignancy is low and the prognosis is positive. Surgical resection is often the first choice, and long-term follow-up is required.

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.

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.

Clinical and Pathological Features of Primary Renal Well-Differentiated Neuroendocrine Tumor

Primary carcinoid tumor of the kidney is an extremely rare well-differentiated neuroendocrine tumor, which is generally a low-grade malignant cancer with a good prognosis. Carcinoid tumors are rarely found in the urinary system. Here, we report a 34-year-old woman with primary renal well-differentiated neuroendocrine tumor who underwent nephron sparing surgery and no evidence of recurrence or distant metastasis was found during routine follow-up. We searched the case of renal carcinoid with the search phrase "carcinoid [title] and kidney [title]" and "carcinoid [title] and renal [title]" using the PubMed and restricted the search to articles published in English since 2013. The clinical manifestations, age, sex, tumor size, location, gross pathology, light microscopy and immunohistochemistry were analyzed. A total of 28 cases of renal carcinoid were retrieved from PubMed. Higher proportion of positive labeling of CgA, Syn, NSE and CD56 are most valuable in the diagnosis of primary renal well-differentiated neuroendocrine tumor. At present, radical nephrectomy remains the gold standard in the curative-intent therapy for well-differentiated neuroendocrine carcinoma of kidney, in metastatic renal carcinoid, long-term use of octreotide may be an effective adjuvant therapy.

18F-FDG PET/CT and 68Ga-DOTATATE PET/CT Findings in a Patient With Primary Renal Well-Differentiated Neuroendocrine Tumor

ABSTRACT

Primary renal well-differentiated neuroendocrine tumors (WDNETs), also called renal carcinoids, are extremely rare. Since first described in 1966, approximately 100 cases have been reported in the literature. However, there have been no cases shown by PET/CT to date. We presented a patient with primary renal WDNET who had undergone both 68Ga-DOTATATE PET/CT and 18F-FDG PET/CT for diagnosis and staging. This case illustrated that 68Ga-DOTATATE PET/CT scanning could play a role in the diagnosis, staging, and follow-up of primary renal WDNETs.

Single institutional experience on primary neuroendocrine neoplasms of the kidney: a rare distinct entity

Primary pure renal neuroendocrine neoplasms (R-NENs) are a distinct and rare entity. Not much is known about the histopathology and biologic behavior of these tumors. We attempted to review the clinicopathologic aspects of these neoplasms encountered at our institution. We performed a retrospective chart review to identify primary pure (not admixed with any other tumor component) R-NENs from institutional Cancer Registry database. Pathologic review of the diagnostic archival slides was done for detailed assessment of the histologic features. R-NENs were classified according to the current WHO system for gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs). Eight pure R-NEN cases were identified, all unifocal, and most (6/8) involved the right kidney. Three patients had poorly differentiated neuroendocrine carcinoma (NEC), and five had well-differentiated neuroendocrine tumor (NET). All tumors were located near the renal hilum, stained diffusely with synaptophysin, variably with chromogranin, and were negative for renal site-specific marker PAX8 or for markers of renal cell carcinoma. We identified two distinct patterns of growth: one of sheets with interspersed rosettes and the other of large nests with low proliferative crowded centers and peripheral cells with higher proliferation and prominent palisading. Based on Ki-67 proliferative index, the tumors were classifiable into WHO grade 1 or grade 2 (based on GEP-NEN). All three NECs characteristically showed cytologic features intermediate between classic large and small cell type. This is the first comprehensive clinicopathologic study involving the rare group of R-NEN. Classifying and grading them according to the GEP-NEN system is of prognostic significance.

Primary Renal Carcinoid: Two Rare Cases at a Single Center

Renal carcinoid tumors are exceedingly rare. These neuroendocrine masses are most frequently found in the gastrointestinal and respiratory tracts. A renal carcinoid tumor has only been documented in around 100 cases. In this article, we report two additional cases in female patients ages 53 and 63. Both tumors were found incidentally on computed tomography scans. Both women underwent radical nephrectomies. Neither has shown evidence of metastasis nor relapse to date; however, the 63-year-old woman was lost to follow-up. In conclusion, upon discovery of the asymptomatic renal mass, renal carcinoid should be a consideration in the differentiation, and if suspected, may be treated with radical nephrectomy as was done in our hospital.

Primary Renal Carcinoid Tumor: Report of Two Cases

INTRODUCTION

Primary renal carcinoid tumors are a rare subset of neuroendocrine tumors arising in the kidneys. Although carcinoid syndrome has occasionally been described, most patients are asymptomatic at presentation.

CASE PRESENTATIONS

We present 2 cases of primary renal carcinoid tumor and describe the workup, immunohistochemical analysis, treatment, and surveillance of each female patient. The first patient was found to have a renal mass on imaging during a workup of chronic abdominal pain and subsequently underwent a robotic radical nephrectomy. The second patient was found to have an incidental renal mass on imaging and subsequently underwent renal biopsy, followed by robot-assisted laparoscopic partial nephrectomy. In both cases, a gallium dotatate Ga 68-enhanced positron emission tomography/computed tomography scan was used to further assess disease burden.

DISCUSSION

This report describes 2 cases of primary renal carcinoid tumor with unique presentations and management in our regional health care system. Because primary renal carcinoid tumors are quite uncommon, there are no clear established guidelines on preoperative imaging or posttreatment surveillance in patients with these tumors. There remains a large amount of variability in the diagnosis, workup, immunohistochemical analysis, treatment, and surveillance of patients with primary renal carcinoid tumors. As we learn more about this disease, we hope to optimize patient outcomes and standardize pretreatment workup and posttreatment surveillance.

Renal Neuroendocrine Neoplasms: A Single-center Experience

BACKGROUND

Primary neuroendocrine neoplasms (NENs) of the kidney are exceedingly rare malignancies and the available literature is very limited. The natural history and response to treatments is not well characterized. We aimed to describe the presenting features, demographics, tumor characteristics, and treatment outcomes of patients with renal NENs.

PATIENTS AND METHODS

We performed a retrospective analysis of all Mayo Clinic patient records with a tissue diagnosis of a primary renal NEN. Baseline patient and surgical pathologic features and treatment modalities were collected. Time to recurrence after resection and overall survival (OS) were estimated using with survival analysis. Surveillance, Epidemiology, and End Results data were used to estimate the population-wide incidence and OS.

RESULTS

A total of 17 patients were included in the present study, with a median follow-up of 62.8 months. Distant metastasis was present in 29% at diagnosis, with 76% experiencing distant metastasis at any point; 24% had a horseshoe kidney. Of the 17 patients, 14 had undergone surgical resection with no evidence of disease postoperatively. Ten of these patients had documented recurrence. The median time to recurrence was 18 months (95% confidence interval, 9-46 months). Only 1 of the 10 patients showed a radiographic response to systemic therapy. Of 9 patients, 4 had stable disease with somatostatin analogs. The median OS was 143 months (95% confidence interval, 50-143 months).

CONCLUSIONS

Renal NENs are rare malignancies affecting mostly middle-age patients, with distant metastasis being common. Approximately one half of patients experience stable disease with somatostatin analogs. The OS usually exceeds 5 years.