Renal cell carcinoma with rhabdoid features: an aggressive neoplasm with overexpression of p53

Sarcomatoid and Rhabdoid Renal Cell Carcinoma: Clinical, Pathologic, and Molecular Genetic Features

Renal cell carcinoma (RCC) with sarcomatoid and rhabdoid morphologies has an aggressive biological behavior and a typically poor prognosis. The current 2022 WHO classification of renal tumors does not include them as distinct histologic entities but rather as transformational changes that may arise in a background of various distinct histologic types of RCC. The sarcomatoid component shows malignant spindle cells that may grow as intersecting fascicles, which is reminiscent of pleomorphic undifferentiated sarcoma. The rhabdoid cells are epithelioid cells with eccentrically located vesicular nuclei with prominent nucleoli and large intracytoplasmic eosinophilic inclusions. Studies have shown that RCCs with sarcomatoid and rhabdoid differentiation have distinctive molecular features. Sarcomatoid RCC harbors shared genomic alterations in carcinomatous and rhabdoid components, but also enrichment of specific genomic alterations in the sarcomatoid element, suggesting molecular pathways for development of sarcomatoid growth from a common clonal ancestor. Rhabdoid differentiation also arises through clonal evolution although less is known of specific genomic alterations in rhabdoid cells. Historically, treatment has lacked efficacy, although recently immunotherapy with PD-1/PD-L1/CTLA-4 inhibitors has produced significant clinical responses. Reporting of sarcomatoid and rhabdoid features in renal cell carcinoma is required by the College of American Pathologists and the International Collaboration on Cancer Reporting. This manuscript reviews the clinical, pathologic, and molecular features of sarcomatoid RCC and rhabdoid RCC with emphasis on the morphologic features of these tumors, significance of diagnostic recognition, the molecular mechanisms of tumorigenesis and differentiation along sarcomatoid and rhabdoid lines, and advances in treatment, particularly immunotherapy.

Prognostic factors in renal cell carcinoma: A single‑center study

Renal cell carcinoma (RCC) is a heterogeneous and complex disease with numerous pathophysiologic variants. ~40% of patients succumb due to the progression of the disease, making RCC the most fatal of the common urologic malignancies. Prognostic factors are indicators of the progression of the disease, and the precise determination of these factors is important for evaluating and managing RCC. In the present study, it was aimed to determine and find associations among the histopathological features of RCCs and their impact on survival and metastasis. This is a cross-sectional study of RCC cases who have undergone partial or radical nephrectomy from March 2008 to October 2021 and have been pathologically reviewed at Shorsh General Teaching Hospital in Sulaimani, Iraq. The data in the pathology studies were supplemented by follow-up of the patients to obtain information about survival, recurrence and metastasis. In total, 228 cases of RCC were identified, among whom 60.5% were men and 39.5% were women, with a median age of 51 years. The main tumor types were clear cell RCC (71.1%), papillary RCC (13.6%), and chromophobe RCC (11%). Various measures of aggressiveness, including tumor necrosis, sarcomatoid change, microvascular invasion, and parameters of invasiveness (invasion of the renal sinus and other structures), were significantly correlated with each other, and they were also associated with reduced overall survival and an increased risk of metastasis on univariate analysis. However, on multivariate analysis, only tumor size and grade, and microvascular invasion retained statistical significance and were associated with a lower survival rate. In conclusion, pathological parameters have an impact on prognosis in RCC. The most consistent prognostic factors can be tumor size and grade, and microvascular invasion.

Hot topics in renal cancer pathology: implications for clinical management

INTRODUCTION

The updated European Association of Urology (EAU) Guidelines issued a weak recommendation for adjuvant pembrolizumab for patients with high-risk operable clear cell Renal Cell Carcinoma (ccRCC). High risk of recurrence was defined, as per protocol-criteria, as T2 with nuclear grade 4 or sarcomatoid differentiation, T3 or higher, regional lymph node metastasis, or stage M1 with no evidence of disease. Considering the heterogeneous population included in the recommendation, it has been questioned if adjuvant pembrolizumab may lead to overtreatment of some patients as well as undertreatment of patients with worse prognosis.

AREAS COVERED

In this review, we discuss the issues related to the assessment of pathological features required to identify those patients harboring a high-risk tumor, highlighting the issue related to interobserver variability and discuss the currently available prognostic scoring systems in ccRCC.

EXPERT OPINION

PPathologist assessment of prognostic features suffers from interobserver variability which may depend on gross sampling and the pathologist's expertise. The presence of clear cell feature is not sufficient criteria by itself to define ccRCC since clear cell can be also found in other histotypes. Application of molecular biomarkers may be useful tools in the near future to help clinicians identify patients harboring tumors with worse prognosis.

The significance of sarcomatoid and rhabdoid dedifferentiation in renal cell carcinoma

Dedifferentiation in renal cell carcinoma (RCC), either sarcomatoid or rhabdoid, is an infrequent event that may occur heterogeneously in the setting of any RCC histology and is associated with poor outcomes. Sarcomatoid dedifferentiation is associated with inferior survival with angiogenesis targeted therapy and infrequent responses to cytotoxic chemotherapy. However, immune checkpoint therapy has significantly improved outcomes for patients with sarcomatoid dedifferentiation. Biologically, sarcomatoid dedifferentiation has increased programmed death-ligand 1 (PD-L1) expression and an inflamed tumor microenvironment, in addition to other distinct molecular alterations. Less is known about rhabdoid dedifferentiation from either a clinical, biological, or therapeutic perspective. In this focused review, we will discuss the prognostic implications, outcomes with systemic therapy, and underlying biology in RCC with either sarcomatoid or rhabdoid dedifferentiation present.

Immunotherapies in Genitourinary Oncology: Where Are We Now? Where Are We Going?

Simple Summary

Genitourinary malignancies include cancers along the urinary tract and the male reproductive tract, encompassing the adrenal glands, kidneys, bladder, prostate, and testicles. Immunotherapy, which treats cancer by using the immune system to attack malignant cells, has historically been successful in treating some types of genitourinary cancers, especially of the bladder and kidney. In the past decade, a more precise method of immunotherapy, known as immune checkpoint inhibition, has gained popularity as it enhances the immune system’s ability to recognize and destroy tumor cells. Several immune checkpoint inhibitors have achieved success in patients with advanced genitourinary cancers. This review provides a brief overview of traditional immunotherapies, focuses on how immune checkpoint inhibitors have achieved success in patients with advanced cancers, and investigates the role for immunotherapy in genitourinary malignancies in the future.

Abstract

For decades, limited options existed to treat metastatic genitourinary cancers, including treatment options that could be classified as immunotherapy. Historically, immunotherapy centered on systemic cytokines for the treatment of metastatic kidney cancer, which had several adverse effects, as well as the Bacillus Calmette–Guérin vaccine for non-metastatic bladder cancer. Within the past decade, advances in immunotherapy have led to several approvals from the United States Food and Drug Administration, particularly in the field of immune checkpoint inhibition. Immune checkpoint inhibitors (ICIs) are now being used extensively to treat multiple solid tumors, including kidney and bladder cancers, and they are also being tested in many other cancers. Despite encouraging data from phase 2/3 clinical trials, less is known about biomarkers that may predict better response to ICIs. The effect of ICIs in genitourinary cancers is heterogeneous, with some tumor types having little clinical data available, or ICIs having limited activity in other tumors. In this review, we briefly discuss approved immunotherapy agents prior to the time of ICIs. Then, given the emergence of this class of agents, we summarize the several important ICIs and the clinical trials that led to their approval. Finally, we mention ongoing and future clinical trials.

The significance of SMARCB1 in the pathogenesis of renal cell carcinoma with rhabdoid features

BACKGROUND

Renal cell carcinoma with rhabdoid features (RCC-RF) is an aggressive histologic variant in the adults and is usually unresponsive to standard chemotherapy.

METHODS

Expression of SMARCB1/INI1 was examined in primary RCC-RF (n = 5). Stable INI1 with/without prostaglandin E2 receptor 1 (EP1) knockdown cell lines were created in the ACHN and 786-O RCC cell lines and measured for epidermal growth factor receptor (EGFR)-related signaling pathways. Chemosensitivity to targeted drugs in vitro was tested after knocking down of INI1 in both cell lines. The outcome of co-targeting of INI1 and EP1 in RCC was examined using a tumorigenicity assay.

RESULTS

Expression of INI1 was markedly reduced at both transcriptional and translational levels in primary RCC-RF. Immunohistochemical expression of INI1 protein was lost in the nuclei of rhabdoid cells compared with conventional RCC (n = 8). Using two cell lines with different genetic background, we showed that knocking down of INI1 activates the EGFR signaling with up-regulated AKT and ERK pathways and sensitizes cancer cells to Erlotinib treatment in vitro. However, cell-line dependent effects were also demonstrated with reference to impact of INI1 or EP1 on cell growth, migration and response to Gefitinib or Everolimus treatment in vitro.

CONCLUSION

Inactivation of INI1 may play a role in the pathogenesis of RCC-RF. Erlotinib is recommended in the management of patients with INI1-related RCC.

Systemic Therapies for the Management of Non-Clear Cell Renal Cell Carcinoma: What Works, What Doesn't, and What the Future Holds

Non-clear cell renal cell carcinoma (nccRCC) is a broad term that refers to a diverse group of tumors, each with its own distinct biologic and therapeutic profile. The management of nccRCCs is often based on extrapolating data from clinical trials in the more common clear cell renal cell carcinoma, but our emerging prospective and retrospective clinical experience in nccRCC allows us to make more precise recommendations tailored to each histology. The systemic therapy options for metastatic nccRCC include targeted therapies such as tyrosine kinase inhibitors, immune checkpoint inhibitors, and, for specific rare subtypes, cytotoxic chemotherapy. Each nccRCC histology may respond differently to these regimens, which makes accurate pathologic diagnosis imperative. In the present review, we discuss the available clinical and biological data that can help guide systemic therapy recommendations for specific nccRCC subtypes.

Infiltrative Renal Malignancies: Imaging Features, Prognostic Implications, and Mimics

Infiltrative renal malignancies are a subset of renal masses that are morphologically characterized by a poorly defined interface with the renal parenchyma. Infiltrative renal malignancies are less common but more aggressive than more typical renal malignancies and carry an overall worse prognosis. Although an infiltrative renal process often represents a malignant neoplasm, infiltrative masses include a wide spectrum of diseases including primary renal cortical, medullary, and pelvic tumors; lymphoproliferative processes; metastases; and various infectious, inflammatory, immune-mediated, and vascular mimics. The imaging features of these masses are often nonspecific, but with the appropriate history, laboratory results, and clinical context, the radiologist can help narrow the diagnosis and guide further treatment. An invited commentary by Lee is available online.Online supplemental material is available for this article. ^©RSNA, 2021.

Updates in Histologic Grading of Urologic Neoplasms

CONTEXT.—

Tumor histology offers a composite view of the genetic, epigenetic, proteomic, and microenvironmental determinants of tumor biology. As a marker of tumor histology, histologic grading has persisted as a highly relevant factor in risk stratification and management of urologic neoplasms (ie, renal cell carcinoma, prostatic adenocarcinoma, and urothelial carcinoma). Ongoing research and consensus meetings have attempted to improve the accuracy, consistency, and biologic relevance of histologic grading, as well as provide guidance for many challenging scenarios.

OBJECTIVE.—

To review the most recent updates to the grading system of urologic neoplasms, including those in the 2016 4th edition of the World Health Organization (WHO) Bluebook, with emphasis on issues encountered in routine practice.

DATA SOURCES.—

Peer-reviewed publications and the 4th edition of the WHO Bluebook on the pathology and genetics of the urinary system and male genital organs.

CONCLUSIONS.—

This article summarizes the recently updated grading schemes for renal cell carcinoma, prostate adenocarcinomas, and bladder neoplasms of the genitourinary tract.

Ipilimumab and Nivolumab as First-Line Treatment of Patients with Renal Cell Carcinoma: The Evidence to Date

Immunotherapy has revolutionized the management of metastatic renal cell carcinoma with four checkpoint inhibitors (nivolumab, ipilimumab, avelumab, and pembrolizumab) approved either as monotherapy or as combination therapy. The use of ipilimumab and nivolumab for treatment-naïve, intermediate to poor risk, metastatic renal cell carcinoma was the first checkpoint inhibitor-based combination therapy and remains the only dual checkpoint inhibitor combination approved in mRCC. In this article, we review the trials that led to the approval of ipilimumab and nivolumab in this setting. We also highlight the ongoing trials using this combination, its use in special populations, and clinically relevant unanswered questions.

Renal cell carcinoma with rhabdoid features: A rare aggressive and fatal variant

Renal cell carcinoma with rhabdoid features is a rare histopathologic variant recently documented. It is a very aggressive tumor and associated with a higher mortality rate and poor prognosis. A 22 years old female patient presents with a rare case of clear cell renal cell carcinoma with rhabdoid features successfully managed with right radical nephrectomy and paracaval lymph node excision. The patient was alive, healthy and three years of flow up for the patient was free from metastasis. Despite rhabdoid features are lethal tumors and are associated with higher grades, radical nephrectomy with lymph node dissection increases survival rate.

Complete and Prolonged Response of Renal Cell Carcinoma With Rhabdoid Features to Checkpoint Inhibitor Therapy

Checkpoint inhibitor immunotherapy has recently been proven to be an attractive treatment option for a wide variety of malignancies. Nivolumab, an anti-programmed cell death protein-1 antibody, has been proven effective and safe in treating metastatic renal cell carcinoma (RCC) with a clear cell component. We report the case of a patient with high-grade clear cell RCC with rhabdoid features who has achieved a durable complete response with nivolumab therapy after multiple surgical interventions and progression on pazopanib. Genomic evaluation in this case was characterized in part by a PBRM1 variant, similar to the only other described case of RCC with rhabdoid features obtaining a complete response to nivolumab. This case supports the potential utility of checkpoint inhibitors in aggressive, rare subtypes of RCC where there are limited options for therapy.

Dataset for the reporting of renal biopsy for tumour: recommendations from the International Collaboration on Cancer Reporting (ICCR)

The International Collaboration on Cancer Reporting (ICCR) has developed a suite of detailed datasets for international implementation. These datasets are based on the reporting protocols developed by the Royal College of Pathologists (UK), The Royal College of Pathologists of Australasia and the College of American Pathologists, with modifications undertaken by international expert groups appointed according to ICCR protocols. The dataset for the reporting of renal biopsy for tumour is designed to provide a structured reporting template containing minimum data recording key elements suitable for international use. In formulating the dataset, the ICCR panel incorporated recommendations from the 2012 Vancouver Consensus Conference of the International Society of Urological Pathology (ISUP) and the 2016 edition of the WHO Bluebook on tumours of the urinary and male genital systems. Reporting elements were divided into Required (Core) and Recommended (Non-core) components of the report. Required elements are as follows: specimen laterality, histological tumour type, WHO/ISUP histological tumour grade, sarcomatoid morphology, rhabdoid morphology, necrosis, lymphovascular invasion and coexisting pathology in non-neoplastic kidney. Recommended reporting elements are as follows: operative procedure, tumour site(s), histological tumour subtype and details of ancillary studies. In particular, it is noted that fluorescence in situ hybridisation studies may assist in diagnosing translocation renal cell carcinoma (RCC) and in distinguishing oncocytoma and eosinophilic chromophobe RCC. It is anticipated that the implementation of this dataset into routine clinical practice will facilitate uniformity of pathology reporting worldwide. This, in turn, should have a positive impact on patient treatment and the quality of demographic information held by cancer registries.

Data set for the reporting of carcinoma of renal tubular origin: recommendations from the International Collaboration on Cancer Reporting (ICCR)

AIMS

The International Collaboration on Cancer Reporting (ICCR) has provided detailed data sets based upon the published reporting protocols of the Royal College of Pathologists, the Royal College of Pathologists of Australasia and the College of American Pathologists.

METHODS AND RESULTS

The data set for carcinomas of renal tubular origin treated by nephrectomy was developed to provide a minimum structured reporting template suitable for international use, and incorporated recommendations from the 2012 Vancouver Consensus Conference of the International Society of Urological Pathology (ISUP) and the fourth edition of the World Health Organisation Bluebook on tumours of the urinary and male genital systems published in 2016. Reporting elements were divided into those, which are required and recommended components of the report. Required elements are: specimen laterality, operative procedure, attached structures, tumour focality, tumour dimension, tumour type, WHO/ISUP grade, sarcomatoid/rhabdoid morphology, tumour necrosis, extent of invasion, lymph node status, surgical margin status, AJCC TNM staging and co-existing pathology. Recommended reporting elements are: pre-operative treatment, details of tissue removed for experimental purposes prior to submission, site of tumour(s) block identification key, extent of sarcomatoid and/or rhabdoid component, extent of necrosis, presence of tumour in renal vein wall, lymphovascular invasion and lymph node status (size of largest focus and extranodal extension).

CONCLUSIONS

It is anticipated that the implementation of this data set in routine clinical practice will inform patient treatment as well as provide standardised information relating to outcome prediction. The harmonisation of data reporting should also facilitate international research collaborations.

Grading of renal cell carcinoma

Grading of renal cell carcinoma (RCC) has been recognised as a prognostic factor for almost 100 years. Numerous grading systems have been proposed, initially focusing upon a constellation of cytological features and more recently on nuclear morphology. It has been recommended that grading of RCC should be based upon nucleolar prominence/eosinophilia for grades 1-3, while grade 4 requires nuclear anaplasia (including tumour giant cells, sarcomatoid differentiation and/or rhabdoid morphology). The grading system was adopted formally by the International Society of Urological Pathology (ISUP) and subsequently by the World Health Organisation (WHO), being designated the WHO/ISUP grading classification in the fourth edition of the WHO classification tumours of the urinary system and male genital organs (2016). This grading system has been validated for both clear cell and papillary RCC. Validation studies for chromophobe RCC failed to demonstrate a correlation between grade and outcome for both the superseded Fuhrman grading system and the WHO/ISUP grading classification, and it has been recommended that these tumours not be graded. The WHO/ISUP system has been incorporated into the structured reports of the International Cancer Collaboration on Cancer Reporting for both clear cell and papillary RCC. It is also noted that other types of RCC may be graded, but it must be emphasised in the report that this is for descriptive and diagnostic purposes, and not outcome prediction. More recent studies have shown the incorporation of the presence of tumour necrosis into RCC grading to improve outcome prediction, and this has been validated in several studies.

WHO/ISUP classification, grading and pathological staging of renal cell carcinoma: standards and controversies

PURPOSE

Pathological parameters assessed on biopsies and resection specimens have a pivotal role in the diagnosis, prognosis and management of patients with renal cell carcinoma (RCC).

METHODS

A non-systematic literature search was performed, updated to January 2018, to identify key standards and controversies in the pathological classification, grading and staging of RCC.

RESULTS

Although most RCCs exhibit characteristic morphology that enables easy categorisation, RCCs show considerable morphological heterogeneity and it is not uncommon for there to be difficulty in assigning a tumour type, especially with rarer tumour subtypes. The differentiation between benign and malignant oncocytic tumours remains a particular challenge. The development of additional immunohistochemical and molecular tests is needed to facilitate tumour typing, because of the prognostic and therapeutic implications, and to enable more reliable identification of poorly differentiated metastatic tumours as being of renal origin. Any new tests need to be applicable to small biopsy samples, to overcome the heterogeneity of renal tumours. There is also a need to facilitate identification of tumour types that have genetic implications, to allow referral and management at specialist centres. Digital pathology has a potential role in such referral practice.

CONCLUSION

Much has been done to standardise pathological assessment of renal cell carcinomas in recent years, but there still remain areas of difficulty in classification and grading of these heterogeneous tumours.

Molecular and Metabolic Basis of Clear Cell Carcinoma of the Kidney

Renal cell carcinoma (RCC) is a heterogenous group of tumors, >70% of which belong to the category of clear cell carcinoma. In recent years, crucial advances have been made in our understanding of the molecular and metabolic basis of clear cell carcinoma. This tumor manifests significant alterations in the cellular metabolism, so that the tumor cells preferentially induce the hypoxia response pathway using aerobic glycolysis, rather than the normal oxidative phosphorylation for energy. Most of the clear cell carcinomas (sporadic as well as familial) have mutations and deletions in the VHL gene located at 3p (p3.25). Normally, pVHL plays a crucial role in the proteasomal degradation of hypoxia-inducible factors (HIF)1 and HIF2. Lack of a functioning pVHL owing to genetic alterations results in stabilization and accumulation of these factors, which promotes cell growth, cell proliferation, and angiogenesis, contributing to a neoplastic phenotype. Several other genes normally located adjacent to VHL (BAP1, SETD2, PBRM1) may also be lost. These are tumor suppressor genes whose loss not only plays a role in carcinogenesis but may also influence the clinical course of these neoplasms. In addition, interaction among a variety of other genes located at several different chromosomes may also play a role in the genesis and progression of clear cell carcinoma.

Intratumoral morphologic and molecular heterogeneity of rhabdoid renal cell carcinoma: challenges for personalized therapy

Rhabdoid histology in clear-cell renal cell carcinoma is associated with a poor prognosis. The prognosis of patients with clear-cell renal cell carcinoma may also be influenced by molecular alterations. The aim of this study was to evaluate the association between histologic features and salient molecular changes in rhabdoid clear-cell renal cell carcinoma. We macrodissected the rhabdoid and clear-cell epithelioid components from 12 cases of rhabdoid clear-cell renal cell carcinoma. We assessed cancer-related mutations from eight cases using a clinical next-generation exome-sequencing platform. The transcriptome of rhabdoid clear-cell renal cell carcinoma (n=8) and non-rhabdoid clear-cell renal cell carcinoma (n=37) was assessed by RNA-seq and gene expression microarray. VHL (63%) showed identical mutations in all regions from the same tumor. BAP1 (38%) and PBRM1 (13%) mutations were identified in the rhabdoid but not in the epithelioid component and were mutually exclusive in 3/3 cases and 1 case, respectively. SETD2 (63%) mutations were discordant between different histologic regions in 2/5 cases, with mutations called only in the epithelioid and rhabdoid components, respectively. The transcriptome of rhabdoid clear-cell renal cell carcinoma was distinct from advanced-stage and high-grade clear-cell renal cell carcinoma. The diverse histologic components of rhabdoid clear-cell renal cell carcinoma, however, showed a similar transcriptomic program, including a similar prognostic gene expression signature. Rhabdoid clear-cell renal cell carcinoma is transcriptomically distinct and shows a high rate of SETD2 and BAP1 mutations and a low rate of PBRM1 mutations. Driver mutations in clear-cell renal cell carcinoma are often discordant across different morphologic regions, whereas the gene expression program is relatively stable. Molecular profiling of clear-cell renal cell carcinoma may improve by assessing for gene expression and sampling tumor foci from different histologic regions.

MicroRNA-451a is associated with cell proliferation, migration and apoptosis in renal cell carcinoma

MicroRNAs (miRNAs) are an important class of small, non‑coding RNA molecules that regulate gene expression at the transcriptional or post‑transcriptional level. They are involved in apoptosis, proliferation and migration and are known to have an important role in many types of cancer. Aberrant expression of miRNA‑451a (miR‑451a) has previously been reported in tumors, however its role in renal cell carcinoma (RCC) is currently unknown. The aim of the present study was to investigate the role of miR‑451a in RCC. The expression of miR‑451a was analyzed in 50 paired RCC and normal tissues by quantitative polymerase chain reaction. Furthermore, the effects of miR‑451a on cell migration, proliferation and apoptosis were evaluated, using migration scratch, MTT and flow cytometric assays. The present study demonstrated that miR‑451a was upregulated in RCC, as compared with paired normal tissues (P<0.05). Downregulation of miR‑451a using a synthesized inhibitor, significantly suppressed cell migration and proliferation, and induced apoptosis of renal cancer cells in vitro, as compared with a negative control (P<0.05). In the present study, it was determined that miR‑451a may have an important role as a tumor enhancer in RCC. These results imply that miR‑451a may be a promising therapeutic target for the treatment of RCC.

Concurrent occurrence of renal cell carcinoma with rhabdoid features in a married couple: a case report

Background

Renal cell carcinoma (RCC) with rhabdoid features is a rare histology and exhibits clinically aggressive behavior. We report a case of a married couple in whom RCC with rhabdoid features concurrently occurred. The rarity of this event suggests that environmental factors may contribute to the etiology of RCC with rhabdoid features.

Case presentation

A 76-year-old Japanese woman was diagnosed with a hypervascular mass in the right kidney and tumor thrombus extending into the right atrium by enhanced computed tomography (CT). She underwent radical nephrectomy and tumor thrombectomy following systemic therapy with the tyrosine kinase inhibitor sunitinib. The histological evaluation denoted clear cell RCC with rhabdoid features. The patient died of cancer 12 months postoperatively. A 76-year-old man, her husband, presented with gross hematuria 2 weeks after his wife had undergone surgery. He had a long history of asbestos exposure. An abdominal CT scan revealed a hypervascular mass in the right kidney and tumor thrombus extending into the inferior vena cava. He also underwent radical nephrectomy and tumor thrombectomy. The histological evaluation also showed clear cell RCC with rhabdoid features. Bone metastasis occurred 12 months postoperatively, but he died of an unrelated cause 18 months after surgery.

Conclusion

Concurrent occurrence of RCC with rhabdoid features may not to be coincidental. Although further studies are warranted, asbestos exposure may contribute to the etiology of clear cell RCC with rhabdoid features.

Diagnostic approach to eosinophilic renal neoplasms

CONTEXT

Eosinophilic renal neoplasms include a spectrum of solid and papillary tumors ranging from indolent benign oncocytoma to highly aggressive malignancies. Recognition of the correct nature of the tumor, especially in biopsy specimens, is paramount for patient management.

OBJECTIVE

To review the diagnostic approach to eosinophilic renal neoplasms with light microscopy and ancillary techniques.

DATA SOURCES

Review of the published literature and personal experience.

CONCLUSIONS

The following tumors are in the differential diagnosis of oncocytic renal cell neoplasm: oncocytoma, chromophobe renal cell carcinoma (RCC), hybrid tumor, tubulocystic carcinoma, papillary RCC, clear cell RCC with predominant eosinophilic cell morphology, follicular thyroid-like RCC, hereditary leiomyomatosis-associated RCC, acquired cystic disease-associated RCC, rhabdoid RCC, microphthalmia transcription factor translocation RCC, epithelioid angiomyolipoma, and unclassified RCC. In low-grade nonpapillary eosinophilic neoplasms, distinction between oncocytoma and low-grade RCC mostly rests on histomorphology; however, cytokeratin 7 immunostain may be helpful. In high-grade nonpapillary lesions, there is more of a role for ancillary techniques, including immunohistochemistry for cytokeratin 7, CA9, CD10, racemase, HMB45, and Melan-A. In papillary eosinophilic neoplasms, it is important to distinguish sporadic type 2 papillary RCC from microphthalmia transcription factor translocation and hereditary leiomyomatosis-associated RCC. Histologic and cytologic features along with immunohistochemistry and fluorescence in situ hybridization tests for TFE3 (Xp11.2) and TFEB [t(6;11)] are reliable confirmatory tests. Eosinophilic epithelial neoplasms with architecture, cytology, and/or immunoprofile not qualifying for either of the established types of RCC should be classified as unclassified eosinophilic RCC and arbitrarily assigned a grade (low or high).

Rhabdoid differentiation is associated with aggressive behavior in renal cell carcinoma: a clinicopathologic analysis of 76 cases with clinical follow-up

Rhabdoid differentiation has been associated with aggressive behavior in carcinomas from different organ systems. A recent consensus statement of the International Society of Urological Pathology (ISUP), in addition to proposing a nucleolar grading system (ISUP grade) for renal cell carcinoma (RCC) to replace the Fuhrman system, recommended reporting the presence of rhabdoid differentiation in RCC and considering tumors with rhabdoid differentiation to be ISUP grade 4. Although it has been shown that rhabdoid differentiation is associated with increased grade and stage of RCC, it has not been fully demonstrated whether it has an adverse effect independent of this association with increased grade and stage. We provide the largest clinicopathologic analysis of RCC with rhabdoid differentiation to date (76 cases), including characterization of metastatic disease. In addition, by constructing a multivariable model including tumor grade, stage, necrosis, and distant metastasis to compare a series of 49 clear cell RCC with rhabdoid differentiation with a cohort of 41 clear cell RCCs without rhabdoid differentiation, we demonstrate that the presence of rhabdoid differentiation in clear cell RCC confers an increased risk of death (hazard ratio=5.25; 95% confidence interval, 2.1-14.3) independent of these other adverse prognostic factors. These findings underscore the significance of rhabdoid differentiation in RCC as an adverse prognostic factor and support the recent reporting and grading recommendations of the ISUP.

Hereditary leiomyomatosis and renal cell carcinoma (HLRCC): a rapid autopsy report of metastatic renal cell carcinoma

Rapid ("warm") autopsies of patients with advanced metastatic cancer provide invaluable insight into the natural history, pathobiology, and morphology of advanced and treatment-resistant tumors. Here, we report a rapid autopsy case of a hereditary leiomyomatosis and renal cell carcinoma (HLRCC) patient with advanced metastatic renal cell carcinoma (RCC)-the first such case described for either a primary renal tumor or HLRCC-related cancer. Mutations in the fumarate hydratase (FH) gene underlie HLRCC, a rare syndrome involving cutaneous and uterine leiomyomata and aggressive kidney tumors. Loss of heterozygosity at the wild-type FH gene locus results in profound cellular metabolic derangement, "pseudohypoxic" upregulation of hypoxia-inducible factor 1α (HIF-1α)-dependent transcription, and aberrant protein succination; these molecular changes drive oncogenesis of kidney tumors in HLRCC patients. The current index patient had a high-grade RCC with classic morphologic features of HLRCC, including large nuclei with prominent eosinophilic nucleoli and perinucleolar clearing. In addition, this patient's RCC demonstrated extensive sarcomatoid and rhabdoid features-morphologies not previously well described in HLRCC-associated kidney tumors. Here, we report the extent of metastatic dissemination and supplement this unique tumor morphology with mitochondrial enzyme histochemistry and extended immunohistochemical analysis. Tumor cells strongly expressed PAX8, vimentin, CD10, and the HIF target GLUT1 and showed increased nuclear p53 accumulation; the expression of other RCC markers was negative. We also detail microscopic tubular epithelial changes in the grossly uninvolved ipsilateral renal parenchyma and demonstrate sporadic, aberrant upregulation of the HIF targets GLUT1 and CAIX in dysplastic peritumoral tubules.

Renal cell carcinoma with rhabdoid and sarcomatoid features presented as a metastatic thigh mass with an unusual immunohistochemical profile

Renal cell carcinoma (RCC) may metastasize anywhere in the body and sometimes the primary tumor is missing and necessitates extensive investigations to detect. In this report, we describe a case of RCC metastasizing to the thigh in a 70 year old male with a highly pleomorphic morphology suggesting a high grade sarcoma that showed unequivocal positivity for desmin directing the diagnosis for pleomorphic rhabdomyosarcoma. After completion of 33 cycles of radiotherapy, the patient developed large intraabdominal mass that showed conventional areas of RCC with immunoreactivity for CD10, CK, EMA, carbonic anhydrase IX and vimentin. The tumor cells in other areas resembled that of thigh mass which raised suspicions whether the two masses represented the same tumor or not. Surprisingly, the tumor cells of thigh mass showed diffuse positivity for CD10 and focal expression for CK, EMA and carbonic anhydrase IX. Extensive investigations failed to detect any primary renal lesions. The present case demonstrated that RCC can metastasize to virtually any body site and can have significant morphologic overlap with other non-renal neoplasms. Absence of primary origin of RCC according to radiological and operative data should not hinder the diagnosis of metastatic RCC. RCC with sarcomatoid and rhabdoid features carries aggressive behavior manifested by great metastatic potential and short survival time.

Histologic variations and immunohistochemical features of metastatic clear cell renal cell carcinoma

BACKGROUND

Due to advancements in treatment of metastatic and advanced renal cell carcinoma (RCC), it has become increasingly important to diagnose metastatic RCC and the specific subtype. In this study, we investigated the diverse histologic features of metastatic clear cell renal cell carcinoma (CCRCC) cases in comparison with corresponding primary lesions.

METHODS

We identified 119 metastatic CCRCC cases from 81 corresponding primary lesions diagnosed between 1995 and 2010 and evaluated the diverse histologic and immunohistochemical features of these lesions.

RESULTS

A total of 44 primary lesions (54.3%) had a non-clear cell component in addition to a typical clear cell component. Of the 119 metastatic lesions, 63 lesions (52.9%) contained a non-clear cell component, and 29 metastatic lesions were composed of a non-clear cell component only. Rhabdoid features were the most frequent non-clear cell histology among the metastatic lesions. Metastatic CCRCCs mainly showed positive CD10 and epithelial membrane antigen staining and negative cytokeratin 7 staining.

CONCLUSIONS

Metastatic CCRCC commonly showed a variety of histologic features. If there is a difficulty to diagnose metastatic CCRCC due to a variety of histologic features or small biopsy specimen, histologic review of the primary lesion and immunohistochemical analysis can help determine the correct diagnosis.

Sarcomatoid renal cell carcinoma with rhabdoid features

Sarcomatoid renal cell carcinoma (SRCC) with rhabdoid features is a rare tumor with aggressive behavior and poor prognosis. We report a case of a 71-year-old man with a large left-sided renal mass. Nephrectomy specimen revealed clear cell carcinoma with sarcomatoid and rhabdoid tumor cells. The rhabdoid cells were immunoreactive for mesenchymal markers such as vimentin, epithelial markers such as cytokeratin, and epithelial membrane antigen. These cells were also positive for p53 and had a high proliferation index. The rhabdoid component also demonstrated the loss of immunostaining for integrase interactor 1 (INI1), which stained the other components of the tumor. Only a few cases are available in the published reports documenting rhabdoid cells in SRCC. None of these cases were studied by INI1 immunostain.

Extensive peritoneal carcinomatosis secondary to renal cell carcinoma with sarcomatoid and rhabdoid differentiation

Renal cell carcinoma (RCC), the most common malignancy of kidney, originates from renal tubular epithelium. It is subclassified based on histological and molecular features. Rarely, RCC can show focal to extensive sarcomatoid or rhabdoid differentiation. RCC with extensive sarcomatoid differentiation and no identifiable epithelial component is designated as unclassified RCC with sarcomatoid differentiation. Presence of sarcomatoid or rhabdoid differentiation is associated with poor prognosis. We describe autopsy findings in a case of RCC with extensive sarcomatoid and focal rhabdoid differentiation presenting with malignant ascites secondary to peritoneal carcinomatosis and multiorgan metastasis.

MicroRNA-141 is downregulated in human renal cell carcinoma and regulates cell survival by targeting CDC25B

Background/objective

MicroRNAs (miRNAs) are small noncoding RNAs (ribonucleic acids), approximately 22 nucleotides in length, that function as regulators of gene expression. Dysregulation of miRNAs has been associated with the initiation and progression of oncogenesis in humans. The cell division cycle (CDC)25 phosphatases are important regulators of the cell cycle. Their abnormal expression detected in a number of tumors implies that their dysregulation is involved in malignant transformation.

Methods

Using miRNA target prediction software, we found that miR-141 could target the 3′ untranslated region (3′UTR) sequence of CDC25B. To shed light on the role of miR-141 in renal cell carcinogenesis, the expression of miR-141 was examined by real-time polymerase chain reaction (RT-PCR) in renal cell carcinoma and normal tissues. The impact of miR-141 re-expression on 769-P cells was analyzed using 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and colony-forming assay. A luciferase reporter assay was applied to prove the functionality of the miR-141 binding site.

Results

miR-141 is significantly downregulated in renal cell carcinoma. miR-141 re-expression suppressed cell growth in 769-P cells. Luciferase expression from a reporter vector containing the CDC25B-3′UTR was decreased when this construct was transfected with miR-141 in 769-P cells. The overexpression of miR-141 suppressed the endogenous CDC25B protein level in 769-P cells.

Conclusion

For the first time, we demonstrated that CDC25B is a direct target of miR-141 in renal cell carcinoma. The transcriptional loss of miR-141 and the resultant increase in CDC25B expression facilitates increased genomic instability at an early stage of renal cell carcinoma development.

Knockdown of Cdc25B in renal cell carcinoma is associated with decreased malignant features

Cdc25 phosphatases are important regulators of the cell cycle. Their abnormal expression detected in a number of tumors implies that their dysregulation is involved in malignant transformation. However, the role of Cdc25B in renal cell carcinomas remains unknown. To shed light on influence on renal cell carcinogenesis and subsequent progression, Cdc25B expression was examined by real-time RT-PCR and western blotting in renal cell carcinoma and normal tissues. 65 kDa Cdc25B expression was higher in carcinomas than in the adjacent normal tissues (P<0.05), positive correlations being noted with clinical stage and histopathologic grade (P<0.05). To additionally investigate the role of Cdc25B alteration in the development of renal cell carcinoma, Cdc25B siRNA was used to knockdown the expression of Cdc25B. Down-regulation resulted in slower growth, more G2/M cells, weaker capacity for migration and invasion, and induction of apoptosis in 769-P transfectants. Reduction of 14-3-3 protein expression appeared related to Cdc25B knockdown. These findings suggest an important role of Cdc25B in renal cell carcinoma development and provide a rationale for investigation of Cdc2B-based gene therapy.

Treatment of adult rhabdoid renal cell carcinoma with sorafenib

Renal cell carcinoma (RCC) with rhabdoid features is an uncommon and highly aggressive malignancy. We report a case of adult clear-cell RCC with extensive rhabdoid features treated with the tyrosine kinase inhibitor sorafenib. A review of the literature summarizes important aspects of this malignancy. We discuss clinical and histological findings as well as the patient's response to sorafenib therapy.

Adult renal cell carcinoma with rhabdoid morphology represents a neoplastic dedifferentiation analogous to sarcomatoid carcinoma

Renal cell carcinoma (RCC) with rhabdoid morphology (RCC-RM) is a recently described variant of RCC, which has an aggressive biologic behavior and poor prognosis, akin to sarcomatoid RCC. The current World Health Organization classification of RCC does not include the rhabdoid phenotype as a distinct histologic entity. The aim of this study is to investigate whether RCC-RM represents a dedifferentiation of a classifiable-type World Health Organization RCC or a carcinosarcoma with muscle differentiation. We reviewed 168 cases of RCC obtained between 2003 and 2008. From these cases, 10 (6%) were found to have areas of classic rhabdoid morphology. Immunohistochemistry for cytokeratin, epithelial membrane antigen, desmin, CD10, and CD117 was performed in each case using the labeled streptavidin-biotin method. Rhabdoid differentiation was identified in association with conventional-type RCC (9) and with unclassifiable-type RCC with spindle cell morphology (1). In all cases, both the rhabdoid and nonrhabdoid tumoral areas were positive for cytokeratin and epithelial membrane antigen and negative for desmin. Cytokeratin positivity in the rhabdoid areas was focal. In cases associated with conventional-type RCC, CD10 was positive in both the rhabdoid and nonrhabdoid foci. CD117 was negative in these tumors. The unclassifiable-type RCC with spindle cell morphology was negative for both CD10 and CD117. The similar immunophenotype between the rhabdoid and nonrhabdoid tumoral foci supports the origin of the rhabdoid cells from the classifiable-type RCC. Areas of rhabdoid morphology do not represent muscle metaplastic differentiation. Renal cell carcinoma with rhabdoid morphology may represent a dedifferentiation of a classifiable-type RCC, similar to that of sarcomatoid differentiation. The recognition of RCC-RM is important as it allows for the inclusion of these high-grade malignancies into a category associated with poor prognosis despite lacking the spindle cell component classically identified as sarcomatoid change.

Acquired cystic disease-associated renal cell carcinoma with sarcomatoid change and rhabdoid features

Acquired cystic disease (ACD)-associated renal cell carcinoma (RCC) is a recently described entity. To the best of our knowledge, there are no reports of ACD-associated RCC with sarcomatoid and rhabdoid changes. In this article, we present the first case of such a tumor. A 56-year-old Japanese man has received long-term hemodialysis and had a history of right renal cancer. Following the discovery of metastatic cancer in the thoracic wall, detailed imaging studies revealed a mass in the left kidney. The histologic examination of the left renal tumor showed ACD-associated RCC with sarcomatoid change and rhabdoid features. Immunohistochemically, intracytoplasmic globular inclusions in rhabdoid cells were positive for vimentin and cytokeratin CAM5.2. The G-band karyotype showed the following changes: 46, X, +X. -Y[1]/43, idem, add(2)(q31), -6, -9, -14, -15, +16, -22, +mar1[6]/46, XY[2]/abnormal cell[11]. In conclusion, pathologists and urologists should be aware that rhabdoid features may occur in ACD-associated RCC and that the loss of chromosomes 9 and 14 may occur during the process of sarcomatoid change in ACD-associated RCC.

Protein kinase C-alpha is expressed and activated during the development of renal cell carcinoma

OBJECTIVES

To evaluate protein kinase C-alpha (PKCalpha) expression in human renal cell carcinoma (RCC) tissues and cell lines, and its clinical significance.

METHODS

Expression of PKCalpha was analyzed by Western blot in 90 clinical specimens. The expression of PKCalpha in the cytoplasm or plasma membrane was correlated to clinical stage and grade to assess for potential relationships. A human renal cell carcinoma (RCC) cell line (786-O/PKCalpha) was generated with stable expression of a fusion protein of green fluorescent protein (GFP) and PKCalpha, to facilitate analysis of in situ compartmentalization of PKCalpha during activation.

RESULTS

PKCalpha expression and the ratio of PKCalpha expression in the membrane (M) to that in cytosol (C) were greater in cancerous tissues than in normal tissues (P <.05). With an increase in tumor grade and stage, the level of PKCalpha increased significantly in membrane (P <.01) and decreased in cytosol (P <.01). Consistently, there was an increase of M/C with increasing malignancy of tumor. As expected, the translocation of PKCalpha between plasma membrane and cytosol could be observed in 786-O renal carcinoma cells with the treatment of PKCalpha agonist or inhibitor.

CONCLUSIONS

We demonstrated differential PKCalpha expression in RCC tissues, indicating that abnormal PKCalpha activation may contribute to the development of RCC.

Advances and controversies in grading and staging of renal cell carcinoma

Despite the considerable progress made in our understanding of the pathogenesis, genetics, and pathology of renal cell carcinoma (RCC), difficulties remain relating to the prediction of clinical outcome for individual cases. Although there is evidence to show that high-grade tumors have a poorer prognosis when compared to those of low grade, debate remains regarding the predictive value of grading, especially for those tumors classified into the intermediate grades. Numerous composite morphologic and nuclear grading systems have been proposed for RCC and although that of the Fuhrman classification have achieved widespread usage, the validity of the grading criteria of this classification has been questioned. In addition, there are few studies that have attempted to validate the Fuhrman system for RCCs beyond that of the clear cell subtype. Recent studies have indicated that grading of papillary RCC should be based on nucleolar prominence alone and that the components of the Fuhrman grading classification do not provide prognostic information for chromophobe RCC. Independent of tumor grade, the prognostic importance of tumor stage for RCC is well recognized. The Union Internationale Contre le Cancer/American Joint Committee for Cancer Staging and End Results Reporting TNM staging system is now in its sixth edition (2002) and recent refinements have focused on defining size cut points that will identify apparently localized tumors that will develop recurrence and/or metastases despite attempted curative surgery. In parallel with these studies it has been shown that infiltration of the renal sinus is an important prognostic factor, being observed in almost all tumors >7 cm in diameter. Questions remain as to the appropriate stratification of regional extension of RCC, as defined in the T3 tumor-staging category. Recent modifications to this category have been suggested combining the level of infiltration of the venous outflow tract with the presence or absence of infiltration of the adrenal gland and/or perirenal fat. Similarly, the utility of classifying lymph node involvement by tumor is debated, although it is well recognized that lymph node infiltration is associated with a poor prognosis. Although the current TNM classification does provide useful prognostic information it would appear that further modifications are justified to enhance the predictive value of staging for RCC.