Papillary renal cell carcinoma with cytologic and molecular genetic features overlapping with renal oncocytoma: Analysis of 10 cases

What Is New in Pathologic Diagnosis and Classification of the Common Renal Cell Neoplasms?

Diagnostic challenges remain among the common renal cell carcinoma (RCC) subtypes. High-grade clear cell RCC may have deceptive patterns, for example BAP1-deficient tumors. Subtyping type 1 and 2 papillary RCC is no longer recommended, as former type 2 tumors may now be contain other diagnostic entities, such as FH-deficient RCC, MITF family RCC, or others. Clear cell papillary tumor is no longer considered carcinoma due to its highly favorable behavior. However, imperfect examples are best considered clear cell RCC. Oncocytic renal neoplasm of low malignant potential has been proposed as a borderline category in the absence of overt malignant features.

Multinucleated tumor cells and micropapillary morphology appear to be predictors of poor prognosis in renal cell carcinoma with papillary and oncocytic features

Renal cell carcinoma with papillary and oncocytic features (RCC-PO) are poorly understood, partially due to conflicting results in multiple studies. The histological features that predict behavior of RCC-PO have not been elucidated. The aim is to review clinicopathologic features and to correlate clinical outcomes of patients with RCC-PO to further expand our knowledge on these heterogeneous tumors. An archival search was done for "RCC" and "papillary," and tumors with >50% papillary and oncocytic features were included. Clinicopathologic data including tumor size, grade, stage, molecular and immunohistochemical testing when performed, and follow-up data were collected. Using multivariate analyses, correlation between histological features, tumor stage and prognosis were analyzed. Sixty-one patients with RCC-PO were identified of which 49 (80%) were male with a median age of 65 (range: 36-93) years, and a mean tumor size of 5.2 (range: 1-21.5) cm. Micropapillary features were seen in 4, bizarre nuclei (at least 3 times larger or with irregular shape) in 6, multinucleated tumor cells (MTC) in 15, single or small clusters (SSC) (made of 2-3 tumor cells) located away from areas of necrosis in 16, and striking eosinophilic cytoplasmic inclusions in 3 tumors, respectively. Thirty-six (59%) tumors were high-grade (WHO/ISUP grade 3-4), and 23 (38%) had a high stage (≥pT3 or pN1). Tumors were positive for AMACR (15/16) and CK7 (13/17), with preserved FH (7/7) staining and were all negative for CD117 (0/7), ALK, TFE3, cathepsin K, Melan A, and HMB45 (0/4, each). Three tumors underwent chromosomal microarray (CMA) plus gene fusion assay, and FISH and germline testing for FLCN and MET gene alterations by PCR were done on 1 each. Ten (16%) patients had a local recurrence (LR) or metastasis after nephrectomy; 4 died of disease (2 had tumors with micropapillary features), with a median follow-up of 7 (range: 0.01-19) years. Tumors with micropapillary features showed significantly higher RCC-PO-related mortality (50% vs. 3.5%, p < 0.001). In multivariable analysis, SSC correlated with a higher stage (HR: 11.95; p = 0.005); micropapillary features (HR: 18.42; p = 0.017) and MTC (HR: 180.22; p = 0.036) with presence of metastasis/LR; and micropapillary features with a higher RCC-PO-related mortality (HR: 60.35; p = 0.036). RCC-PO are cytogenetically heterogeneous with overlapping features of various renal neoplasms. Micropapillary features and MTC appear to be independent predictors of poor outcomes in these tumors.

Immunotherapy treatment for sarcomatoid renal cell carcinoma: case report and literature review

Introduction

Sarcomatoid renal cell carcinoma (SRCC) is clinically rare, accounting for ~1.0-1.5% of renal parenchymal tumors. Although the concept of SRCC was proposed in 1968, the molecular mechanisms and immunological characteristics of sarcomatoid changes remain unclear. In the era of targeted therapy, the overall survival (OS) of patients with SRCC is typically less than 12 months.

Case presentation

This article reports a case of SRCC in an 81-year-old male. Progression-free survival (PFS) was as long as 25 months and OS was 30 months after immunotherapy and the effect was significant. This is the first report of successful use toripalimab in the treatment of SRCC.

Clinical discussion

SRCC is a rare type of renal cancer with no obvious specific clinical manifestations or imaging findings, and the diagnosis of the disease is based on pathological examinations. SRCC has a high degree of malignancy, progresses rapidly, and has a poor prognosis. The effect of traditional treatment is limited, and immune checkpoint inhibitors may have therapeutic potential.

Conclusions

Toripalimab may be effective and further exploration is anticipated to advance a new period of SRCC.

Prognostic value of CDCA3 in kidney renal papillary cell carcinoma

Kidney renal papillary cell carcinoma (KIRP) is a type of low-grade malignant renal cell carcinoma. Huge challenges remain in the treatment of KIRP. Cell division cycle associated 3 (CDCA3) participates in human physiological and pathological processes. However, its role in KIRP has not been established. Here, we evaluated the prognostic value of CDCA3 in KIRP using a comprehensive bioinformatics approach. Data for CDCA3 expression in KIRP were obtained from online database. Different expression genes between high and low CDCA3 expression groups were identified and evaluated by performing Gene ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses. A gene set enrichment analysis was performed to elucidate the function and pathway differences between the different. Differences in immune cell infiltration between low and high CDCA3 expression groups were analyzed by a single-sample GSEA method for immune cells. A protein-protein interaction network was generated and hub genes were identified. UALCAN was used to analyze associations between the mRNA expression levels of CDCA3 in KIRP tissues with clinicopathologic parameters. The diagnostic efficacy of CDCA3 for KIRP was analyzed by ROC analysis. Logistic regression was used to analyze relationships between the clinicopathological characteristics and CDCA3 expression. Our results indicated that high CDCA3 mRNA expression is significantly associated with some clinicopathologic parameters in KIRP patients High CDCA3 mRNA expression associated with a shorter overall survival, progression-free interval, and disease-special survival. Taken together, CDCA3 is a potential target for the development of anti-KIRP therapeutics and is an efficient prognostic marker.

Immunohistochemistry for the diagnosis of renal epithelial neoplasms

Despite the increasing number of newly identified renal neoplasms, the diagnosis of renal cell carcinoma (RCC) can usually be reached with careful histologic examination and a limited immunohistochemical (IHC) panel. Clear cell, papillary, chromophobe RCC and oncocytoma account for more than 90% of renal neoplasia in adults, and sophisticated ancillary tools are usually unnecessary. Renal tumors with entity-defining genetic alterations may ultimately require molecular confirmation via cytogenetics or sequencing technologies, such as RCC with TFE3, TFEB, or ALK gene rearrangements, or TFEB amplified RCC. In fumarate hydratase-deficient and succinate dehydrogenase-deficient RCC, highly specific IHC markers can strongly suggest the diagnosis. In the metastatic setting, PAX8 and carbonic anhydrase 9 are among the most helpful markers for confirming RCC and clear cell type, respectively; however, caution should be exercised in the absence of a current or historical renal mass. In diagnostically challenging cases, such as renal eosinophilic tumors with low-grade nuclear features, or infiltrative high-grade tumors, careful examination coupled with a judicious panel of IHC markers usually resolves the diagnosis. This review offers concise algorithms for diagnosis of kidney neoplasia with the latest recognized, provisional, and emerging entities to daily pathology practice.

The Morphological Spectrum of Papillary Renal Cell Carcinoma and Prevalence of Provisional/Emerging Renal Tumor Entities with Papillary Growth

Renal cell carcinoma (RCC) represents a heterogeneous disease, encompassing an increasing number of tumor subtypes. Post-2016, the World Health Organization (WHO) classification recognized that the spectrum of papillary renal cell carcinoma is evolving and has long surpassed the dichotomic simplistic "type 1 versus type 2" classification. The differential diagnosis of pRCC includes several new provisional/emerging entities with papillary growth. Type 2 tumors have been cleared out of several confounding entities, now regarded as independent tumors with specific clinical and molecular backgrounds. In this work we describe the prevalence and characteristics of emerging papillary tumor entities in two renal tumor cohorts (one consisting of consecutive papillary tumors from a single institute, the other consisting of consultation cases from several centers). After a review of 154 consecutive pRCC cases, 58% remained type 1 pRCC, and 34% type 2 pRCC. Papillary renal neoplasm with reversed polarity (1.3%), biphasic hyalinizing psammomatous RCC (1.3%), and biphasic squamoid/alveolar RCC (4.5%) were rare. Among 281 consultation cases, 121 (43%) tumors had a dominant papillary growth (most frequently MiT family translocation RCCs, mucinous tubular and spindle cell carcinoma and clear cell papillary RCC). Our data confirm that the spectrum of RCCs with papillary growth represents a major diagnostical challenge, frequently requiring a second expert opinion. Papillary renal neoplasm with reversed polarity, biphasic hyalinizing psammomatous RCC, and biphasic squamoid/alveolar RCC are rarely sent out for a second opinion, but correct classification and knowledge of these variants will improve our understanding of the clinical behavior of renal tumors with papillary growth.

Renal cell carcinomas with tubulopapillary architecture and oncocytic cells: Molecular analysis of 39 difficult tumors to classify

So-called oncocytic papillary renal cell carcinoma (OPRCC) is a poorly defined variant of papillary renal cell carcinoma. Since its first description, several studies were published with conflicting results, and thus precise definition is lacking. A cohort of 39 PRCCs composed of oncocytic cells were analyzed. Cases were divided into 3 groups based on copy number variation (CNV) pattern. The first group consisted of 23 cases with CNV equal to renal oncocytoma. The second group consisted of 7 cases with polysomy of chromosomes 7 and 17 and the last group of 9 cases included those with variable CNV. Epidemiologic, morphologic and immunohistochemical features varied among the groups. There were not any particular histomorphologic features correlating with any of the genetic subgroups. Further, a combination of morphologic, immunohistochemical, and molecular-genetic features did not allow to precisely predict biologic behavior. Owing to variable CNV pattern in OPRCC, strict adherence to morphology and immunohistochemical profile is recommended, particularly in limited samples (i.e., core biopsy). Applying CNV pattern as a part of a diagnostic algorithm can be potentially misleading. OPRCC is a highly variable group of tumors, which might be misdiagnosed as renal oncocytoma. Using the term OPRCC as a distinct diagnostic entity is, thanks to its high heterogeneity, questionable.

Renal Cell Tumors: Molecular Findings Reshaping Clinico-pathological Practice

Over the past 20 years, the number of subtypes of renal epithelial cell neoplasia has grown. This growth has resulted from detailed histological and immunohistochemical characterization of these tumors and their correlation with clinical outcomes. Distinctive molecular phenotypes have validated the unique nature of many of these tumors. This growth of unique renal neoplasms has continued after the 2016 World Health Organization (WHO) Classification of Tumours. A consequence is that both the pathologists who diagnose the tumors and the clinicians who care for these patients are confronted with a bewildering array of renal cell carcinoma variants. Many of these variants have important clinical features, i.e. familial or syndromic associations, genomics alterations that can be targeted with systemic therapy, and benignancy of tumors previously classified as carcinomas. Our goal in the review is to provide a practical guide to help recognize these variants, based on small and distinct sets of histological features and limited numbers of immunohistochemical stains, supplemented, as necessary, with molecular features.

Assessing Genomic Copy Number Alterations as Best Practice for Renal Cell Neoplasia: An Evidence-Based Review from the Cancer Genomics Consortium Workgroup

Renal cell neoplasia are heterogeneous with diverse histology, genetic alterations, and clinical behavior that are diagnosed mostly on morphologic features. The Renal Cell Neoplasia Workgroup of the Cancer Genomics Consortium systematically evaluated peer-reviewed literature on genomic studies of renal cell carcinoma (RCC), including clear cell RCC, papillary RCC, chromophobe RCC, and the translocation RCC involving TFE3, TFEB and MITF rearrangements, as well as benign oncocytoma, which together comprise about 95% of all renal cell neoplasia. The Workgroup curated recurrent copy number alterations (CNAs), copy-neutral loss-of-heterozygosity (cnLOH), rearrangements, and mutations, found in each subtype and assigned clinical relevance according to established criteria. In clear cell RCC, loss of 3p has a disease-initiating role and most likely also in progression with mutations detected in VHL and other genes mapped to this arm, and loss of 9p and/or 14q has well-substantiated prognostic utility. Gain of chromosomes 7 and 17 are hallmark CNAs of papillary RCC, but patterns of other CNAs as detected by chromosomal microarray analysis (CMA) afford sub-classification into Type 1 and 2 with prognostic value, and for further sub-stratification of Type 2. Inherent chromosome loss in chromophobe RCC as detected by CMA is useful for distinguishing the eosinophilic variant from benign oncocytoma which in contrast exhibits few CNAs or rearranged CCND1, but share mitochondrial DNA mutations. In morphologically atypical RCCs, rearrangement of TFE3 and TFEB should be considered in the differential diagnosis, portending an aggressive RCC subtype. Overall, this evidence-based review provides a validated role for assessment of CNAs in renal cell neoplasia in the clinical setting to assist in renal cell neoplasm diagnosis and sub-classification within subtypes that is integral to the management of patients, from small incidentally found renal masses to larger surgically resected specimens, and simultaneously identify the presence of key alterations portending outcome in malignant RCC subtypes.

The Labyrinth of Renal Cell Carcinoma

Renal cell carcinoma (RCC) ranks in the top-ten list of malignancies both in males and females [...].

Molecular Genetics of Renal Cell Tumors: A Practical Diagnostic Approach

Renal epithelial cell tumors are composed of a heterogeneous group of tumors with variable morphologic, immunohistochemical, and molecular features. A "histo-molecular" approach is now an integral part of defining renal tumors, aiming to be clinically and therapeutically pertinent. Most renal epithelial tumors including the new and emerging entities have distinct molecular and genetic features which can be detected using various methods. Most renal epithelial tumors can be diagnosed easily based on pure histologic findings with or without immunohistochemical examination. Furthermore, molecular-genetic testing can be utilized to assist in arriving at an accurate diagnosis. In this review, we presented the most current knowledge concerning molecular-genetic aspects of renal epithelial neoplasms, which potentially can be used in daily diagnostic practice.

Expanding the morphologic spectrum of chromophobe renal cell carcinoma: A study of 8 cases with papillary architecture

Although typically arranged in solid alveolar fashion, chromophobe renal cell carcinoma (RCC) may also show several other architectural growth patterns. We include in this series 8 chromophobe RCC cases with prominent papillary growth, a pattern very rarely reported or only mentioned as a feature of chromophobe RCC, which is lacking wider recognition The differential diagnosis of such cases significantly varies from the typical chromophobe RCC with its usual morphology, particularly its distinction from papillary RCC and other relevant and clinically important entities. Of 972 chromophobe RCCs in our files, we identified 8 chromophobe RCCs with papillary growth. We performed immunohistochemistry and array Comparative Genomic Hybridisation (aCGH) to investigate for possible chromosomal aberrations. Patients were 3 males and 5 females with age ranging from 30 to 84 years (mean 57.5, median 60 years). Tumor size was variable and ranged from 2 to 14 cm (mean 7.5, median 6.6 cm). Follow-up was available for 7 of 8 patients, ranging from 1 to 61 months (mean 20.1, median 12 months). Six patients were alive with no signs of aggressive behavior, and one died of the disease. Histologically, all cases were composed of dual cell population consisting of variable proportions of leaf-like cells with pale cytoplasm and eosinophilic cells. The extent of papillary component ranged from 15 to 100% of the tumor volume (mean 51%, median 50%). Sarcomatoid differentiation was identified only in the case with fatal outcome. Immunohistochemically, all tumors were positive for CK7, CD117 and Hale's Colloidal Iron. PAX8 was positive in 5 of 8 cases, TFE3 was focally positive 3 of 8 tumors, and Cathepsin K was focally positive in 2 of 8 tumors. All cases were negative for vimentin, AMACR and HMB45. Fumarate hydratase staining was retained in all tested cases. The proliferative activity was low (up to 1% in 7, up to 5% in one case). Three cases were successfully analyzed by aCGH and all showed a variable copy number variation profile with multiple chromosomal gains and losses. CONCLUSIONS: Chromophobe RCC demonstrating papillary architecture is an exceptionally rare carcinoma. The diagnosis can be challenging, although the cytologic features are consistent with the classic chromophobe RCC. Given the prognostic and therapeutic implications of accurately diagnosis other RCCs with papillary architecture (i.e., Xp11.2 translocation RCC, FH-deficient RCC), it is crucial to differentiate these cases from chromophobe RCC with papillary architecture. Based on this limited series, the presence of papillary architecture does not appear to have negative prognostic impact. However, its wider recognition may allow in depth studies on additional examples of this rare morphologic variant.

The Impact Of Succinate Dehydrogenase Gene (SDH) Mutations In Renal Cell Carcinoma (RCC): A Systematic Review

INTRODUCTION

Renal cell cancer (RCC) syndrome is linked to Krebs cycle compartments and their coding genes' alterations like succinate dehydrogenase genes (SDHx). Here we present a systematic review of the SDH genes' mutations and their impact on both RCC diagnosis and prognosis.

METHODS

This systematic review includes any study in which tissue samples of RCC are considered in correlation with the SDHx mutations, microsatellite instability (MSI), and protein expression. For this purpose, a systematic search of MEDLINE (PubMed), Scopus, Embase, and Web of Science databases was conducted and finally 5384 articles were recruited. All studies' content was checked to find the related ones which were 145 articles, which with data extraction were limited to nineteen.

RESULTS

The final selected nineteen studies investigating the SDHx role in RCC tumor genesis were included, among which fifteen were mutation analysis, three were just SDHx protein expression, and two were MSI and mutation analysis studies. A total of 432 RCC patients were reported by SDH mutations, and 64 patients with MSI and SDH expression change were reported in 514 surgically resected renal epithelial tumors. The most common mutation was the single nucleotide variant rs772551056 (c.137G>A) of SDHB. For SDHC, c.380A>G presented in 48 RCC patients, and for SDHA a novel germline mutation c.2T>C: p.M1T in an occasional case of gastrointestinal stromal tumor intricate with RCC.

CONCLUSION

RCC as an aggressive type of kidney cancer needs some biomarkers to be diagnosed exactly. It was shown recently that the succinate dehydrogenase gene variations can provide this diagnostic and prognostic biomarker. For this purpose, SDHB rs772551056 associated with its protein expression alterations can be taken into account. It is possible that a novel mutation of SDHA (c.2T>C: p.M1T) can provide evidence of GIST associated with RCC as well.

Eosinophilic Kidney Tumors: Old and New

Context.—

Eosinophilic cytoplasm is the most common finding of difficult-to-classify kidney tumors. Morphology, cytogenetics, and immunohistochemical stains are discriminatory. This review compares well-recognized tumors such as granular clear cell carcinoma, papillary variants, chromophobe renal cell carcinoma, and oncocytoma and introduces newly described entities of hybrid oncocytic tumors, carcinomas defined by translocations, and carcinomas with deficiencies in the tricarboxylic acid cycle. The focus is on immunostaining, clinical correlations, and differential diagnoses. Representative examples of some entities are presented with elaboration on their workup.

Objective.—

To provide a review of the differential diagnoses for renal neoplasms with eosinophilic cytoplasm and elaborate on methods that may assist with correct identification.

Data Sources.—

Review of current literature on kidney tumors with eosinophilic cytoplasm, as well as the authors' personal experience.

Conclusions.—

Eosinophilic cytoplasm is a feature shared by many kidney tumors. Understanding the morphologic differences and the role of ancillary studies is key when encountering such a tumor.