Prognostic and Therapeutic Impact of the Histopathologic Definition of Parenchymal Epithelial Renal Tumors

Prediction of Fuhrman grade of renal clear cell carcinoma by multimodal MRI radiomics: a retrospective study

AIM

To explore the value of multimodal magnetic resonance imaging (MRI) radiomics combined with traditional radiologist-defined semantic characteristics and conventional (cMRI) and functional MRI (fMRI) texture features in predicting Fuhrman grade of clear cell renal cell carcinoma (ccRCC).

MATERIALS AND METHODS

The data of 89 patients with histopathologically proven ccRCC (low-grade, 54; high-grade, 35) were collected. Texture features were extracted from cMRI (T1- and T2-weighted imaging) and fMRI (Dixon-MRI; blood-oxygen-level dependent [BOLD]-MRI; and susceptibility-weighted imaging [SWI]) images, and the traditional characteristics (TC) were evaluated. Logistic regression analysis was performed to develop models based on TC, cMRI, and fMRI texture features for grading. Receiver operating characteristic (ROC) curve analysis and leave-group-out cross-validation (LGOCV) were performed to test the reliability of combined models.

RESULTS

Two T2-weighted imaging-based, two Dixon_W-based, one Dixon_F-based, one BOLD-based, and three SWI-based texture features, and three TC were extracted for feature selection. TC, cMRI, fMRI, cMRI+fMRI, cMRI+TC, fMRI+TC, and cMRI+fMRI+TC models were constructed. The AUC of the cMRI+fMRI+TC model for differentiating high- from low-grade ccRCC was 0.74, with 81.42% accuracy, 75.93% sensitivity, and 91.43% specificity. The fMRI+TC model exhibited a performance similar to that of the cMRI+fMRI+TC model (p>0.05). The areas under the curve (AUCs) of the fMRI+TC and cMRI+fMRI+TC models were significantly higher than those of the other five models (all p<0.05). For the cMRI+fMRI+TC model, the mean accuracy was 85.40% after 100 LGOCV for the test sets.

CONCLUSION

Multimodal MRI radiomics combined with TC, cMRI, and fMRI texture features may be a reliable quantitative approach for differentiating high-grade ccRCC from low-grade ccRCC.

CT features based preoperative predictors of aggressive pathology for clinical T1 solid renal cell carcinoma and the development of nomogram model

BACKGROUND

We aimed to identify preoperative predictors of aggressive pathology for cT1 solid renal cell carcinoma (RCC) by combining clinical features with qualitative and quantitative CT parameters, and developed a nomogram model.

METHODS

We conducted a retrospective study of 776 cT1 solid RCC patients treated with partial nephrectomy (PN) or radical nephrectomy (RN) between 2018 and 2022. All patients underwent four-phase contrast-enhanced CT scans and the CT parameters were obtained by two experienced radiologists using region of interest (ROI). Aggressive pathology was defined as patients with nuclear grade III-IV; upstage to pT3a; type II papillary renal cell carcinoma (pRCC), collecting duct or renal medullary carcinoma, unclassified RCC or sarcomatoid/rhabdoid features. Univariate and multivariate logistic analyses were used to determine significant predictors and develop the nomogram model. To evaluate the accuracy and clinical utility of the nomogram model, we used the receiver operating characteristic (ROC) curve, calibration plot, decision curve analysis (DCA), risk stratification, and subgroup analysis.

RESULTS

Of the 776 cT1 solid RCC patients, 250 (32.2%) had aggressive pathological features. The interclass correlation coefficient (ICC) of CT parameters accessed by two reviewers ranged from 0.758 to 0.982. Logistic regression analyses showed that neutrophil-to-lymphocyte ratio (NLR), distance to the collecting system, CT necrosis, tumor margin irregularity, peritumoral neovascularity, and RER-NP were independent predictive factors associated with aggressive pathology. We built the nomogram model using these significant variables, which had an area under the curve (AUC) of 0.854 in the ROC curve.

CONCLUSIONS

Our research demonstrated that preoperative four-phase contrast-enhanced CT was critical for predicting aggressive pathology in cT1 solid RCC, and the constructed nomogram was useful in guiding patient treatment and postoperative follow-up.

Impact of Renal Cell Carcinoma Histological Variants on Recurrence After Partial Nephrectomy: A Multi-Institutional, Prospective Study (UROCCR Study 82)

BACKGROUND

The prognostic impact of renal cell carcinoma (RCC) morphotype remains unclear in patients who undergo partial nephrectomy (PN). Our objective was to determine the risk factors for recurrence after PN, including RCC morphotype.

METHODS

Patients with RCC who had undergone PN were extracted from the prospective, national French database, UroCCR. Patients with genetic predisposition, bilateral or multiple tumours, and those who had undergone secondary totalization were excluded. Primary endpoint was 5-year, recurrence-free survival (RFS), and secondary endpoint was overall survival (OS). Risk factors for recurrence were assessed by multivariable Cox regression analysis.

RESULTS

Overall, 2,767 patients were included (70% male; median age: 61 years [interquartile range (IQR) 51-69]). Most (71.5%) of the PN procedures were robot-assisted. Overall, 2,573 (93.0%) patients were recurrence free, and 74 died (2.7%). Five-year RFS was 84.9% (IQR 82.4-87.4). A significant difference in RFS was observed between RCC morphotypes (p < 0.001). Surgical margins (hazard ratio [HR] = 2.0 [95% confidence interval (CI): 1.3-3.2], p < 0.01), pT stage >1 (HR = 2.6 [95% CI: 1.8-3.7], p < 0.01]) and Fuhrmann grade >2 (HR = 1.9 [95% CI: 1.4-2.6], p < 0.001) were risk factors for recurrence, whereas chromophobe subtype was a protective factor (HR = 0.08 [95% CI: 0.01-0.6], p = 0.02). Five-year OS was 94.0% [92.4-95.7], and there were no significant differences between RCC subgroups (p = 0.06). The main study limitation was its design (multicentre national database), which may be responsible for declarative bias.

CONCLUSIONS

Chromophobe morphotype was significantly associated with better RFS in RCC patients who underwent PN. Conversely, pT stage, Fuhrman group and positive surgical margins were risk factors for recurrence.

Integrated Analysis Revealed the MicroRNA-Based Prognostic Predicting Signature for Papillary Renal Cell Carcinoma

Renal cell carcinoma (RCC) is one of the most frequently occurring tumors worldwide. Herein, we established a microRNA (miRNA) predicting signature to assess the prognosis of papillary-type RCC (PRCC) patients. miR-1293, miR-34a, miR-551b, miR-937, miR-299, and miR-3199-2 were used in building the overall survival (OS)-related signature, whereas miR-7156, miR-211, and miR-301b were used to construct the formula of recurrence-free survival (RFS) with the help of LASSO Cox regression analysis. The Kaplan-Meier and receiver operating characteristic curves indicated good discrimination and efficiency of the two signatures. Functional annotation for the downstream genes of the OS/RFS-related miRNAs exposed the potential mechanisms of PRCC. Notably, the multivariate analyses suggested that the two signatures were independent risk factors for PRCC patients and had better prognostic capacity than any other classifier. In addition, the nomogram indicated synthesis effects and showed better predictive performance than clinicopathologic features and our signatures. We validated the OS and RFS prediction formulas in clinical samples and met our expectations. Finally, we established two novel miRNA-based OS and RFS predicting signatures for PRCC, which are reliable tools for assessing the prognosis of PRCC patients.

Computed tomography features predicting aggressiveness of malignant parenchymal renal tumors suitable for partial nephrectomy

The aim of this study was to identify and standardize computed tomography (CT) features having a potential role in predicting aggressiveness of malignant parenchymal renal tumors suitable for partial nephrectomy (PN). We performed a non-systematic review of the recent literature to evaluate the potential impact of CT variables proposed by the Society of Abdominal Radiology Disease-Focused Panel on Renal Cell Carcinoma in predicting aggressiveness of newly diagnosed malignant parenchymal renal tumors. The analyzed variables were clinical tumor size, tumor growth rate, enhancement characteristics, amount of cystic component, polar and capsular location, tumor margins and distance between tumor and renal sinus. Unfavorable behavior was defined as: 1) renal cell carcinoma (RCC) with stage ≥pT3; 2) nuclear grade 3 or 4; 3) presence of sarcomatoid de-differentiation; or 4) non-clear cell subtypes with unfavorable prognosis (type 2 papillary RCC, collecting duct or renal medullary carcinoma, unclassified RCC). Beyond clinical tumor size, tumor growth rate, enhancement characteristics, amount of cystic component, tumor margins and distance between tumor and renal sinus are highly relevant features predicting an unfavorable behavior. Moreover, several studies supported the role of necrosis as preoperative predictor of tumor aggressiveness. Peritumoral and intratumoral vasculature as well as capsule status are emerging variables that need to be further evaluated. Tumor size, enhancement characteristics, tumor margins and distance to the renal sinus are highly relevant CT features predicting biological aggressiveness of malignant parenchymal renal tumors. Combination of these parameters might be useful to generate tools to predict the unfavorable behavior of renal tumors suitable for PN.

The highest Fuhrman and WHO/ISUP grade influences the Ki-67 labeling index of those of grades 1 and 2 in clear cell renal cell carcinoma

Nuclear grade is one of the most important prognostic factors in clear cell renal cell carcinoma (CCRCC). Although CCRCCs usually have intratumoral heterogeneity with various nuclear atypia including nucleolar prominence, it is unclear whether a similar degree of nuclear grade component demonstrates the same proliferative activity. We aimed to reveal whether the presence of a higher nuclear grade has an effect on proliferative activity among each assigned nuclear grade in CCRCCs. We enrolled 129 CCRCC patients containing at least two different nuclear grades. We separately assessed nuclear grade using the Fuhrman and World Health Organization and International Society of Urologic Pathologists (WHO/ISUP) grading systems. In addition, we selected blocks containing different nuclear grade and assessed the Ki-67 labeling index (LI) for each using a computer-based analysis system. Ki-67 LIs significantly correlated with both Fuhrman and WHO/ISUP grades (P < 0.001 and P < 0.001). Of note, the LIs among Fuhrman and WHO/ISUP grades 1 and 2 were also statistically significant according to the highest nuclear grade (P < 0.01 for both grades 1 and 2). Our data suggests that the highest nuclear grade influences the proliferative activity in tumor components regardless of the morphologically assigned nuclear grades. The exact evaluation of Ki-67 LI in CCRCC can provide a more precise information of the malignant potential.

Immunophenotypic and pathologic heterogeneity of unclassified renal cell carcinoma: a study of 300 cases

Renal cell carcinoma, unclassified (RCC-U), is a heterogenous group of tumors that do not fit in any of the recognized histologic types. Immunohistochemical studies are frequently used to characterize these tumors. Herein, we sought to investigate the immunophenotypes of 300 cases of RCC-U. The cases were morphologically classified into three groups: oncocytoma/chromophobe renal cell carcinoma-like, group 1; clear cell renal cell carcinoma-like, group 2; and others (ie, papillary renal cell carcinoma-like/collecting duct-like/pure sarcomatoid), group 3. The male-to-female ratio was 1.4. Most cases (168, 66%) were group 1. Group 3 was associated with larger tumor size, advanced stage, and frequent lymph node metastases. The most commonly used immunohistochemical stains were CK7 (n = 270; 89.5%), vimentin (n = 186, 82%), CD10 (n = 181; 59.9%), and AMACR (n = 162; 54%). Pancytokeratin (79/101; 78.2%) and PAX8 (54/61; 88.5%) were diffusely positive in most cases, followed by AMACR (69/117; 59%). CD117 was positive in 53 of 118 cases (45%). RCC-U is a morphologically and immunophenotypically heterogenous group of tumors, and comprehensive workup is needed before rendering the diagnosis.

Current management of small renal masses

One of the consequences of the growing use of diagnostic imaging techniques is the notable growth in the detection of small renal masses presumably corresponding to localized tumors that are potentially curable with surgical treatment. When faced with the finding of a small renal mass, radiologists must determine whether it is benign or malignant, and if it is malignant, what subtype it belong to, and whether it should be managed with surgical treatment, with ablative techniques, or with watchful waiting with active surveillance. Small renal masses are now a clinical entity that require management different from the approaches used for classical renal cell carcinomas. In this scenario, radiologists are key because they are involved in all aspects of the management of these tumors, including in their diagnosis, treatment, and follow-up.

Preoperative serum high-density lipoprotein cholesterol as a predictor of poor survival in patients with clear cell renal cell cancer

Purpose:

Numerous studies have suggested that dyslipidemia is closely related to various cancers and the high-density lipoprotein cholesterol (HDL-C) levels are associated with the outcome of cancer patients. However, the predictive value of HDL-C in patients with renal cell carcinoma remains unclear. Our study aims to explore the relationship between the levels of serum HDL-C and the prognosis of renal cell carcinoma.

Methods:

A total of 308 patients diagnosed with clear cell renal cell carcinoma (CCRCC) who received surgical treatment were retrospectively enrolled in our study. The necessary clinical data of each enrolled patient were collected and the Kaplan–Meier method and the Cox proportional hazards regression model were used to calculate the overall survival and cancer-specific survival.

Results:

Kaplan–Meier and univariate analysis showed that a lower preoperative serum HDL-C level was a risk factor of CCRCC patients. Multivariate analyses demonstrated that a higher serum HDL-C level was closely associated with better overall survival (hazard ratio = 0.32; 95% confidence interval (0.13, 0.78); P=0.013) and cancer-specific survival (hazard ratio =0.42; 95% confidence interval (0.15, 0.99); P=0.048).

Conclusion:

Our findings suggest that an increased serum level of HDL-C might predict better overall survival and cancer-specific survival in patients with CCRCC.

Accuracy of renal tumour biopsy for the diagnosis and subtyping of papillary renal cell carcinoma: analysis of paired biopsy and nephrectomy specimens with focus on discordant cases

Aims

Renal tumour biopsy (RTB) is increasingly recognised as a useful diagnostic tool in the management of small renal masses, particularly those that are incidentally found. Intratumoural heterogeneity with respect to morphology, grade and molecular features represents a frequently identified limitation to the use of RTB. While previous studies have evaluated pathological correlation between RTB and nephrectomy, no studies to date have focused specifically on the role of RTB for the diagnosis of papillary renal cell carcinoma (PRCC) and its further subclassification into clinically relevant subtypes.

Methods

This single-institution study evaluated 60 cases of PRCC for concordance between RTB and nephrectomy with respect to diagnosis, grading and subtyping (type 1/type 2).

Results

We observed 93% concordance (55 of 59 evaluable cases) between RTB and nephrectomy for the diagnosis of PRCC, although seven tumours (12%) were undergraded on RTB. Subtyping of PRCC on RTB was concordant with nephrectomy in 89% of cases reported as type 1 PRCC on RTB (31/35), but only 40% of cases reported as type 2 PRCC on RTB (4/10). Morphological misclassification of PRCC on RTB was most likely to occur in tumours showing a solid growth pattern. Discordant PRCC subtyping most often occurred in tumours with eosinophilia/oncocytic change.

Conclusion

There was good concordance between RTB and nephrectomy for the primary diagnosis of PRCC. Although further subtyping of PRCC can aid therapeutic stratification, this can be challenging on RTB and tumours with overlapping or ambiguous features are best reported as PRCC not otherwise specified pending development of more robust methods to facilitate definitive subclassification.

Can preoperative neutrophil lymphocyte ratio predict malignancy in patients undergoing partial nephrectomy because of renal mass?

Purpose:

To evaluate the importance of preoperative neutrophil lymphocyte ratio (NLR) predicting malignancy in patients who undergo partial nephrectomy due to renal mass.

Materials and Methods:

Seventy nine patients who underwent open partial nephrectomy for renal masses were included in this retrospective study. In preoperative routine blood tests, renal ultrasonography and contrast-enhanced computed tomography were performed for all patients. Preoperative neutrophil lymphocyte ratio were compared in patients with clear cell renal cell carcinoma (Group1, 65 patients) and benign lesions (Group 2, 14 patients). The predictive ability of NLR was analyzed by ROC curves and Youden Index method was used to identify the cut-off value for NLR.

Results:

The mean age of patients was 59.8±11.7 years in Group1 and 57.4±12.6 years in Group 2 (p=0.493). The mean tumor size was 3.8±1.2 cm in Group 1 and 3.3±1.0 cm in Group 2 (p=0.07). The median NLR was 2.48 (1.04) in Group 1 and 1.63 (0.96) in Group 2 (p<0.001). The area under a ROC curve was 0.799 (p<0.001).

Conclusions:

Preoperative neutrophil lymphocyte ratio may predict renal masses that can not be distinguished radiologically. Our results must be confirmed by large and properly designed prospective, randomized trials.

Morphological spectrum of renal cell carcinoma, unclassified: an analysis of 136 cases

AIMS

Renal cell carcinoma, unclassified (RCCU) is a category that includes a morphologically and biologically heterogeneous group of tumours that are unable to be diagnosed as other well-defined entities. We aim to describe the morphological findings of tumours within this category and to determine the most frequent morphological features leading to classification difficulty.

METHODS AND RESULTS

One hundred and thirty-six cases of RCCU were examined. Patients ranged in age from 23 to 87 years. Seventy-seven patients were men and 59 were women. International Society of Urological Pathology (ISUP) grade was most commonly 3 (n = 66), followed by 2 (n = 42) and 4 (n = 28). Tumour size ranged from 0.6 to 24.9 cm. The American Joint Committee on Cancer (AJCC) pathological T categories included pT1a (n = 50), pT1b (n = 14), pT2a (n = 7), pT2b (n = 4), pT3a (n = 50) and pT4 (n = 9). Forty-four cases included lymph node(s), 41% of which (n = 18) had metastases. Tumours were assessed for a variety of histological features and assigned to the following morphological groups: predominantly oncocytoma/chromophobe RCC-like; clear cell RCC-like; papillary RCC-like; collecting duct-like; and pure sarcomatoid differentiation. The majority of the oncocytoma/chromophobe and clear cell RCC-like phenotypes were low stage (pT1 or pT2). The papillary RCC-like, collecting duct-like and pure sarcomatoid phenotypes were mainly high stage (pT3 or pT4).

CONCLUSIONS

Renal cell carcinoma, unclassified is a term that encompasses tumours with a variety of morphological features and a wide biological spectrum. The most common source of diagnostic difficulty was tumours composed of predominantly eosinophilic cells.

Safety, reliability and accuracy of small renal tumour biopsies: results from a multi-institution registry

OBJECTIVE

To validate, in a multi-institution review, the safety, accuracy and reliability of renal tumour biopsy (RTB) and its role in decreasing unnecessary treatment.

MATERIALS AND METHODS

We conducted a multi-institution retrospective study of patients who underwent RTB to characterize a small renal mass (SRM) between 2011 and May 2015. Patients were identified using the prospectively maintained Canadian Kidney Cancer information system. Diagnostic and concordance rates were presented using proportions, whereas factors associated with a diagnostic RTB were identified using a logistic regression model.

RESULTS

Of the 373 biopsied SRMs, the initial biopsy was diagnostic in 87% of cases. Of the 47 non-diagnostic biopsies, 15 had a repeat biopsy of which, 80% were diagnostic. When both were combined, therefore, a diagnosis was obtained in 91% of SRMs. Of these, 18% were benign. Size was the only factor found to be associated with achieving a diagnostic biopsy. RTB histology and nuclear grade (high or low) were found to be highly concordant with surgical pathology (86 and 81%, respectively). Of the discordant tumours (n = 16), all were upgraded from low to high grade on surgical pathology. Adverse events were rare (<1% of cases).

CONCLUSION

The present multi-institution study confirms that RTB of SRMs is safe, accurate and reliable across institutions, while decreasing unnecessary treatment. Given our findings, RTBs may be a helpful tool with which to triage SRMs and guide appropriate management.

Introduction to small renal tumours and prognostic indicators

Over the past years, the widespread use of radiological imaging for evaluating abdominal symptoms unrelated to kidney cancer has been linked to a significant increase in the percentage of renal tumours incidentally detected at an asymptomatic stage. The definition of 'small' renal tumours has changed over the years. Presently, according to dimensional criteria, surgical indications and prognostic impact, small renal tumours are defined as masses ≤4 cm in size. Classical preoperative variables that influence the decision-making process in the management of T1a renal tumours can be classified as patient-related and tumour-related factors. Age is an independent predictor of cancer-specific survival (CSS), with older patients exhibiting significantly worse survival. An accurate classification of the anatomical and topographical characteristics of small renal masses based on available nephrometry systems is necessary for standard preoperative evaluation of patients eligible for partial nephrectomy (PN). Renal tumour biopsies (RTBs) can be indicated in patients eligible for active surveillance or ablative treatments, those with other primary tumours, those with prior renal lesions and/or those with multiple synchronous tumours, showing a median diagnostic rate of 92%. Small renal tumours typically have a good prognosis. Patient age, mode of presentation, nuclear grading, coagulative necrosis and histologic subtype can influence the prognosis of this subgroup of RCC.

Preoperative Neutrophil to Lymphocyte Ratio as a Prognostic Factor in Patients with Non-metastatic Renal Cell Carcinoma

BACKGROUND

The neutrophil-to-lymphocyte ratio (NLR) is a strong predictor of mortality in patients with colorectal, lung, gastric cancer, pancreatic and metastatic renal cell carcinoma. We here evaluated whether preoperative NLR is an independent prognostic factor for non-metastatic renal cell carcinoma (RCC).

MATERIALS AND METHODS

Data from 327 patients who underwent curative or palliative nephrectomy were evaluated retrospectively. In preoperative blood routine examination, neutrophils and lymphocytes were obtained. The predictive value of NLR for non-metastatic RCC was analyzed.

RESULTS

The NLR of 327 patients was 2.72±2.25. NLR <1.7 and NLR ≥1.7 were classified as low and high NLR groups, respectively. Chi-square test showed that the preoperative NLR was significantly correlated with the tumor size (P=0.025), but not with the histological subtype (P=0.095)and the pT stage (P=0.283). Overall survival (OS) and disease-free survival (DFS) were assessed using the Kaplan-Meier method. Effects of NLR on OS (P=0.007) and DFS (P=0.011) were significant. To evaluate the independent prognostic significance of NLR, multivariate COX regression models were applied and identified increased NLR as an independent prognostic factor for OS (P=0.015), and DFS (P=0.019).

CONCLUSIONS

Regarding patient survival, an increased NLR represented an independent risk factor, which might reflect a higher risk for severe cardiovascular and other comorbidities. An elevated blood NLR may be a biomarker of poor OS and DFS in patients with non-metastatic RCC.

IgG and IgM glycosylation patterns in patients undergoing image-guided tumor ablation

BACKGROUND

Image-guided tumor ablation is a technique whereby needle-like applicators are placed directly into solid tumors under guidance typically with computed tomography or ultrasound. Changes in IgG and IgM antibody glycosylation were studied during ablation-induced immune response to cancer, and the use of glycosylation as a biomarker for diagnosis, prognosis and disease treatment was examined.

METHODS

Plasma from 27 tumor patients was collected immediately before, after and for 6 months following ablation. IgG and IgM antibodies were isolated by use high-throughput chromatography, and analyzed by hydrophilic liquid chromatography. Thorough identification of glycan structures in each chromatography peak was performed by nano-liquid chromatography electrospray ionization mass spectrometry.

RESULTS

Although antibody glycosylation was found to vary with cancer type, discernable patterns of change based on the successful treatment of tumors by ablation were not identified. One patient with renal clear cell carcinoma and poor disease outcome had unexpectedly high amount of oligomannose IgG glycans during the whole period of monitoring. In contrast, IgM antibodies did not follow the same pattern.

CONCLUSIONS

These findings suggest that glycosylation patterns are indicative of an immune system that is unable to prevent different types of cancer, rather than products of the immunostimulatory response to the ablation of tumor itself. Analyses of the outcome effect suggested that IgG glycosylation and IgM glycosylation are not associated with tumor ablation.

GENERAL SIGNIFICANCE

Present work opens a new way for parallel determination of glycosylation changes of both IgG and IgM antibodies by use of high-throughput methods, and their future use as biomarkers for disease diagnosis and prognosis. This article is part of a Special Issue entitled "Glycans in personalised medicine" Guest Editor: Professor Gordan Lauc.

Clinical applications of diffusion-weighted magnetic resonance imaging in diagnosis of renal lesions - a systematic review

Diffusion-weighted magnetic resonance imaging (DW-MRI) is an established technique to detect the changes of the diffusion of water in biological tissues and reflect the pathophysiological process on the molecular level. It is a promising non-invasive imaging modality in detection of microstructural and functional changes in pathologies of kidney. To systematically review the research advancement of the DW-MRI in diagnosis of renal lesions, a systematic literature search was performed up to 8 October 2014 using the MEDLINE/PubMed and Embase databases for articles reporting on DW-MRI in diagnosis of renal lesions. Only articles with full data about DW-MRI application with potential implication in solving usually encountered clinical challenges about renal lesions were finally examined. The clinical application of DW-MRI allows a better understanding of some pathologic conditions of the kidney including renal insufficiency, renal artery stenosis, ureteral obstruction, foetal kidney disease, hydronephrosis and pyonephrosis. In addition, DW-MRI can also provide clinicians with the information of function evaluation of renal allograft and curative effect assessment of renal tumour. In summary, performance of renal DW-MRI, presuming that measurements are high quality, will further boost this modality, particularly for early detection of diffusion renal conditions, as well as more accurate characterization of renal lesions.

Tumor size, stage and grade alterations of urinary peptidome in RCC

Background

Several promising biomarkers have been found for RCC, but none of them has been used in clinical practice for predicting tumour progression. The most widely used features for predicting tumour aggressiveness still remain the cancer stage, size and grade. Therefore, the aim of our study is to investigate the urinary peptidome to search and identify peptides whose concentrations in urine are linked to tumour growth measure and clinical data.

Methods

A proteomic approach applied to ccRCC urinary peptidome (n = 117) based on prefractionation with activated magnetic beads followed by MALDI-TOF profiling was used. A systematic correlation study was performed on urinary peptide profiles obtained from MS analysis. Peptide identity was obtained by LC–ESI–MS/MS.

Results

Fifteen, twenty-six and five peptides showed a statistically significant alteration of their urinary concentration according to tumour size, pT and grade, respectively. Furthermore, 15 and 9 signals were observed to have urinary levels statistically modified in patients at different pT or grade values, even at very early stages. Among them, C1RL, A1AGx, ZAG2G, PGBM, MMP23, GP162, ADA19, G3P, RSPH3, DREB, NOTC2 SAFB2 and CC168 were identified.

Conclusions

We identified several peptides whose urinary abundance varied according to tumour size, stage and grade. Among them, several play a possible role in tumorigenesis, progression and aggressiveness. These results could be a useful starting point for future studies aimed at verifying their possible use in the managements of RCC patients.

Electronic supplementary material

The online version of this article (doi:10.1186/s12967-015-0693-8) contains supplementary material, which is available to authorized users.

Percutaneous biopsy for risk stratification of renal masses

The increased use of abdominal imaging has led to identification of more patients with incidental renal masses, and renal mass biopsy (RMB) has become a popular method to evaluate unknown renal masses prior to definitive treatment. Pathologic data obtained from biopsy may be used to guide decisions for treatment and may include the presence or absence of malignant tumor, renal cell cancer subtype, tumor grade and the presence of other aggressive pathologic features. However, prior to using RMB for risk stratification, it is important to understand whether RMB findings are equivalent to pathologic analysis of surgical specimens and to identify any potential limitations of this approach. This review outlines the advantages and limitations of the current studies that evaluate RMB as a guide for treatment decision in patients with unknown renal masses. In multiple series, RMB has demonstrated low morbidity and a theoretical reduction in cost, if patients with benign tumors are identified from biopsy and can avoid subsequent treatment. However, when considering the routine use of RMB for risk stratification, it is important to note that biopsy may underestimate risk in some patients by undergrading, understaging or failing to identify aggressive tumor features. Future studies should focus on developing treatment algorithms that integrate RMB to identify the optimal use in risk stratification of patients with unknown renal masses.

Classification of Histologic Patterns of Pseudocapsular Invasion in Organ-Confined Renal Cell Carcinoma

A standardized histologic definition and classification of the patterns of renal tumor pseudocapsular invasion (RTPI) in renal cell carcinoma (RCC) is not available. We classified RTPI into 2 main histologic patterns: expansive and infiltrative RTPI. Patients with organ-confined RCC and infiltrative RTPI had a greater risk of cancer-specific death and might require stricter postoperative surveillance strategies.

INTRODUCTION

A standardized histologic definition and classification of patterns of renal tumor pseudocapsular invasion (RTPI) in renal cell carcinoma (RCC) is not available. The aim of the present study was to propose a classification of RTPI patterns and assess their correlation with other pathologic features and prognosis.

PATIENTS AND METHODS

The renal tumor pseudocapsule was assessed by 2 expert genitourinary pathologists on the histologic slides of 190 specimens from radical nephrectomy performed for organ-confined (pT1-pT2) RCC. The histologic patterns of RTPI were classified and described. The association between the RTPI patterns and other pathologic features was assessed. The Kaplan-Meier method was used to calculate the survival functions, and Cox regression models were used to assess the predictors of cancer-specific survival.

RESULTS

RTPI was classified into 2 main histologic patterns (expansive and infiltrative). Expansive and infiltrative RTPI was observed in 39.5% and 51.6% of cases, respectively. A significant association between the RTPI pattern and Fuhrman grade (P = .006) and RCC histologic subtype (P = .034) was detected. Patients with infiltrative pseudocapsular invasion had significantly poorer 5- and 10-year cancer-specific survival rates than patients with expansive invasion or no invasion (93.6% vs. 98.9% and 84.9% vs. 93%, respectively; P = .039). The presence of infiltrative pseudocapsular invasion was a significant predictor of cancer-specific survival (hazard ratio 4.38, 95% confidence interval 1.04-20.27).

CONCLUSION

An expansive and an infiltrative RTPI pattern can be described. In our study, patients with organ-confined RCC and an infiltrative RTPI pattern had a greater risk of cancer-specific death and might require stricter postoperative surveillance strategies.

Percentage of sarcomatoid component as a prognostic indicator for survival in renal cell carcinoma with sarcomatoid dedifferentiation

OBJECTIVE

Renal cell carcinoma with sarcomatoid dedifferentiation (sRCC) is associated with higher stage of presentation and worse survival. The objective of this study was to examine the clinicopathologic characteristics associated with overall survival (OS), specifically examining the percentage of sarcomatoid component (PSC).

METHODS

We reviewed clinicopathologic data for all nephrectomized patients with confirmed sRCC. Histologic slides were rereviewed by dedicated genitourinary pathologists to ascertain PSC. Patient characteristics were tabulated overall and by disease stage. Cutpoints in the PSC providing a meaningful difference in OS were identified by recursive partitioning analysis (RPA). Factors selected included age group, gender, race, clinical stage, tumor histology, presurgical systemic therapy, lymphovascular invasion, and tumor size. The Kaplan-Meier method and log-rank test were used to assess differences in OS.

RESULTS

Among 186 patients with sRCC, 64 (34%) had localized, and 122 (66%) had metastatic disease at presentation. Patients had primarily clear cell histology (73%). Median follow-up was 12.1 months (range: 0.1-242.2mo). Median OS was 12.6 months (95% CI: 10.7-14.9mo). Univariate RPA identified a PSC cutpoint of 10% as prognostically significant. Patients with PSC>10% were at higher risk of death when compared with patients with PSC≤10% (45% vs. 61% 1-y OS; P = 0.04). Multivariate RPA revealed that tumor size, presence of metastatic disease, and PSC were significantly associated with OS. Among 4 identified groups, patients with localized disease and tumor size≤10cm were most likely to be alive at 1 year (89%), and patients with metastatic disease and PSC>40% were least likely to be alive at 1 year (28%; P<0.001).

CONCLUSION

PSC appears to be a prognostic factor in patients with sRCC, with larger percentage of involvement portending a worse survival, especially in patients with metastatic disease.

Renal Tumor Biopsy for Small Renal Masses: A Single-center 13-year Experience

BACKGROUND

Renal tumor biopsy (RTB) for the characterization of small renal masses (SRMs) has not been widely adopted despite reported safety and accuracy. Without pretreatment biopsy, patients with benign tumors are frequently overtreated.

OBJECTIVE

To assess the diagnostic rate of RTBs, to determine their concordance with surgical pathology, and to assess their impact on management.

DESIGN, SETTING, AND PARTICIPANTS

This is a single-institution retrospective study of 529 patients with biopsied solid SRMs ≤4 cm in diameter. RTBs were performed to aid in clinical management.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Diagnostic and concordance rates were presented using proportions. Factors that contributed to a diagnostic biopsy were identified using a multivariable logistic regression.

RESULTS AND LIMITATIONS

The first biopsy was diagnostic in 90% (n=476) of cases. Of the nondiagnostic biopsies, 24 patients underwent a second biopsy of which 83% were diagnostic. When both were combined, RTBs yielded an overall diagnostic rate of 94%. Following RTB, treatment could have been avoided in at least 26% of cases because the lesion was benign. Tumor size and exophytic location were significantly associated with biopsy outcome. RTB histology and nuclear grade were highly concordant with final pathology (93% and 94%, respectively). Adverse events were low (8.5%) and were all self-limited with the exception of one. Although excellent concordance between RTB and final pathology was observed, only a subset of patients underwent surgery following biopsy. Thus it is possible that some patients were misdiagnosed.

CONCLUSIONS

RTB of SRMs provided a high rate of diagnostic accuracy, and more than a quarter were benign. Routine RTB for SRMs informs treatment decisions and diminishes unnecessary intervention. Our results support its systematic use and suggest that a change in clinical paradigm should be considered.

PATIENT SUMMARY

Renal tumor biopsy (RTB) for pretreatment identification of the pathology of small renal masses (SRMs) is safe and reliable and decreases unnecessary treatment. Routine RTB should be considered in all patients with an indeterminate SRM for which treatment is being considered.

Lessons learned from the comparative study between renal mass biopsy and the analysis of the surgical specimen

INTRODUCTION

The role of renal mass (RM) biopsy is currently under discussion. As a result of the progressive increase in the incidental diagnosis of RMs (which have a higher percentage of benignity and well-differentiated cancers), new approaches have emerged such as observation, especially with elderly patients or those with significant comorbidity. RM biopsy (RMB) should provide sufficient information for making this decision, but so far this has not been the case. We examine our prospective series of in-bench RMBs after surgery and compare them with the anatomy of the removed specimen.

MATERIAL AND METHODS

We obtained (prospectively, in-bench and with a 16-gauge needle) 4 biopsies of RMs operated on in our department from October 2008 to December 2009. These RMs were analyzed by 2 uropathologists and compared with the results of the specimen.

RESULTS

We analyzed 188 biopsies (47 RMs); 12.75% were "not valid". The ability of biopsy to diagnose malignancy or benignity was 100%, and the coincidence in the histological type was 95%. The success in determining the tumor grade was 100% when the cancer was low-grade and 62% when high-grade. None of the analyzed data (necrosis, size, etc.) influenced the results in a statistically significant manner.

CONCLUSION

RMB with a 16-G needle enables the differentiation between malignancy and benignity in 100% of cases, with a very similar diagnostic accuracy in the tumor type. Tumor grade is still the pending issue with renal mass biopsy.

Low preoperative lymphocyte-monocyte ratio (LMR) represents a potentially poor prognostic factor in nonmetastatic clear cell renal cell carcinoma

OBJECTIVES

To explore the potential prognostic significance of the lymphocyte-monocyte ratio (LMR) in patients with nonmetastatic renal cell carcinoma (RCC), as the LMR has been repeatedly proposed to have a negative effect on patient׳s survival in various hematological and solid cancers. However, findings about LMR׳s prognostic significance in RCC have not been reported yet.

METHODS AND MATERIALS

We retrospectively evaluated the prognostic significance of the LMR in a cohort comprising 678 patients with nonmetastatic clear cell RCC, who were operated between 2000 and 2010 with curative radical or partial nephrectomy at a single tertiary academic center. Preoperative LMR was calculated 1 day before surgical intervention. Patients were categorized using an LMR cutoff of 3.0. Cancer-specific survival (CSS), metastasis-free survival, and overall survival were assessed using the Kaplan-Meier method. To evaluate the independent prognostic significance of the LMR, multivariate Cox regression models were applied. Additionally, the influence of the LMR on the predictive accuracy of the Leibovich prognosis score was determined using the Harrell concordance index (c-index) and decision curve analysis.

RESULTS

Low LMR was statistically significantly associated with older patients (≥65 y), high tumor grade (G3+G4), advanced pathologic T category (pT3+pT4), the presence of histologic tumor necrosis, and male gender (P<0.05). Multivariate analysis identified a low LMR as an independent prognostic factor for patients׳ CSS (hazard ratio = 2.33; 95% CI: 1.10-4.94; P = 0.027). The estimated c-index was 0.83 using the Leibovich prognosis score and 0.86 when the LMR was added.

CONCLUSIONS

Regarding CSS of patients with RCC, a decreased LMR represents an independent prognostic factor. Adding the LMR to well-established prognostic models, such as the Leibovich prognosis score, might improve their predictive ability.

Molecular subtyping of metastatic renal cell carcinoma: implications for targeted therapy

BACKGROUND

Renal cell carcinoma (RCC) is known for its ability to metastasize synchronously or metachronously to various anatomic sites. Distinguishing histologic subtypes of metastatic RCC has become increasingly important, as prognosis and therapy can differ dramatically between subtypes. We propose a combination of immunohistochemistry (IHC) and molecular cytogenetics for subtyping metastatic RCC in light of these potential therapeutic implications.

RESULTS

Specimens from 103 cases of metastatic RCC were retrieved, including 32 cases originally diagnosed as metastatic clear cell renal cell carcinoma (CCRCC), 8 as metastatic papillary renal cell carcinoma (PRCC), and 63 metastatic RCC without a specific subtype. Immunohistochemistry was performed with antibodies against cytokeratin 7 (CK7) and alpha-methylacyl-CoA racemase (AMACR). Dual color interphase fluorescence in situ hybridization was utilized to assess for deletion of chromosome 3p and trisomy of chromosomes 7 and 17 in all tumors. Chromosome 3p deletion was detected in 41% of all metastatic RCC specimens, and trisomy of chromosomes 7 and/or 17 was detected in 16%. Of metastatic CCRCC, chromosome 3p deletion was detected in 63%. Of metastatic PRCC, 75% showed trisomy of chromosomes 7 and/or 17. Of the tumors not previously classified, 6% were positive for CK7, and 64% were positive for AMACR; 35% showed chromosome 3p deletion, and 16% showed trisomy of chromosomes 7 and/or 17. Combined analysis of immunohistochemistry and cytogenetics enabled reclassification of 52% of these metastatic tumors not previously classified.

CONCLUSION

Our findings support the utility of immunohistochemistry and cytogenetics for subtyping metastatic RCC.

Can the Leibovich score for clear cell renal cell carcinoma (ccRCC) be accurately reported by a general pathologist?

OBJECTIVES

To evaluate the accuracy of reporting of the Leibovich score (LS) by general pathologists at our centre by comparing the LS in their initial reports with the LS in subsequent review reports by our specialist urological pathologists. We also assessed whether a revision in the LS subsequently altered the risk group.

PATIENTS AND METHODS

In all, 54 consecutive patients had had their initial histology after nephrectomy reported by a general pathologist between August 2008 and March 2012. The histological slides were subsequently re-reviewed by the two specialist urological pathologists and revised LS were given if appropriate. The cases were then discussed at the Uro-oncology Multi disciplinary meeting (MDT) and the reason for the revised LS was discussed with the participating panel and reviewed by the uropathologist.

RESULTS

The general pathologists allocated the 54 patients into low- (13 patients), intermediate- (25) and high-risk (16) categories. After a review of the slides by the specialist urological pathologists and discussion at the MDT meeting the LS was revised in 23 patients (42.6%). The 23 patients who had their LS revised were divided into two groups for the purpose of the present study. On revision of the LS a total of eight patients (14.8%) changed their prognostic group. The change in the prognostic group in the eight patients was increased from intermediate- to high-risk in four patients. There was a reduction in the LS in four patients, which was from high- to intermediate-risk category in one patient and intermediate- to low-risk in three patients.

CONCLUSION

In the present study, histopathology review by a specialist urological pathologist led to a change in LS in 42.6% of cases leading a change in risk grouping in 14.8% of cases. This level of discrepancy is not insignificant. However, the few cases evaluated in the present study does limit robust conclusions and further studies are needed to investigate this issue, so that recommendations can be made to enhance diagnostic accuracy and reproducibility.

Prognostic factors of overall survival in renal cancer patients - single oncological center study

INTRODUCTION

The clinical course of renal cancer remains difficult to predict. Attempts to appoint new independent prognostic factors (IPFs) and comparisons of already identified ones among populations are inevitable to develop more effective prognostic instruments. The aim of this study was to evaluate IPFs of overall survival in a given population of patients with renal cancer.

MATERIALS AND METHODS

Retrospective analysis of 148 patients with renal cancer treated at the Oncological Institute in Cracow from 2000 to 2007 was performed. Mean follow-up was 51 months. Using the log-rang test, a group of clinicopathological and biochemical features was analyzed in respect to their influence on overall survival. Results were presented as Kaplan-Meier curves. Final identification of IPFs was made by multivariate Cox regression analysis.

RESULTS

Overall survival rate at 1, 2, and 5-year follow-up was 58.8%, 38.2%, and 21.4%, respectively. The set of identified IPFs consisted of performance status, smoking history, hemoglobin concentration, anatomical staging, tumor grade, and the presence of microvascular invasion. It was confirmed that only nephrectomy increases significantly overall survival.

CONCLUSIONS

Apart from smoking history, the role of all other IPFs identified in our study is well documented in the literature. Smoking history seems to be a new IPF with strong negative impact on survival in patients with RCC.

High plasma fibrinogen level represents an independent negative prognostic factor regarding cancer-specific, metastasis-free, as well as overall survival in a European cohort of non-metastatic renal cell carcinoma patients

Background:

In recent years, plasma fibrinogen has been ascribed an important role in the pathophysiology of tumour cell invasion and metastases. A relatively small-scale study has indicated that plasma fibrinogen levels may serve as a prognostic factor for predicting clinical outcomes in non-metastatic renal cell carcinoma (RCC) patients.

Methods:

Data from 994 consecutive non-metastatic RCC patients, operated between 2000 and 2010 at a single, tertiary academic centre, were evaluated. Analyses of plasma fibrinogen levels were performed one day before the surgical interventions. Patients were categorised using a cut-off value of 466 mg dl⁻¹ according to a calculation by receiver-operating curve analysis. Cancer-specific (CSS), metastasis-free (MFS), as well as overall survival (OS) were assessed using the Kaplan–Meier method. To evaluate the independent prognostic impact of plasma fibrinogen level, a multivariable Cox regression model was performed for all three different endpoints.

Results:

High plasma fibrinogen levels were associated with various well-established prognostic factors, including age, advanced tumour stage, tumour grade and histologic tumour necrosis (all P<0.05). Furthermore, in multivariable analysis, a high plasma fibrinogen level was statistically significantly associated with a poor outcome for patients' CSS (hazard ratio (HR): 2.47, 95% confidence interval (CI): 1.49–4.11, P<0.001), MFS (HR: 2.15, 95% CI: 1.44–3.22, P<0.001) and OS (HR: 2.48, 95% CI: 1.80–3.40, P<0.001).

Conclusion:

A high plasma fibrinogen level seems to represent a strong and independent negative prognostic factor regarding CSS, MFS and OS in non-metastatic RCC patients. Thus, this easily determinable laboratory value should be considered as an additional prognostic factor for RCC patients' individual risk assessment.

Tumour-associated macrophages might represent a favourable prognostic indicator in patients with papillary renal cell carcinoma

AIMS

Tumour-associated macrophages (TAM) have been reported to be regulators of progression in various human cancers. We evaluated the prognostic relevance of TAM in a large series of patients with papillary renal cell carcinoma (PRCC).

METHODS AND RESULTS

The impact of TAM on cancer-specific survival (CSS) in 177 patients with PRCC was assessed using the Kaplan-Meier method and log-rank test. A multivariate Cox regression analysis was performed with respect to CSS. The presence of TAM was noted in 112 of 177 (63%) tumours and was associated statistically significantly with favourable pathological parameters, including low pathological T stage, node-negative tumours, low tumour grade, absence of vascular invasion and papillary subtype (all P < 0.05), respectively. Five-year CSS probabilities for patients with TAM-positive tumours were 93.5%, compared with 72.5% in patients with TAM-negative tumours, respectively (P < 0.001). Multivariate analysis revealed node-positive tumours, distant metastases and UICC stage (I versus II-IV) as independent predictors of death from PRCC, whereas the presence of TAM was associated independently with favourable outcome (hazard ratio = 0.45, 95% confidence interval 0.24-0.84, P = 0.012).

CONCLUSIONS

The presence of TAM was shown independently to reduce the risk of death from cancer by 55%. The presence of TAM should therefore become part of routine pathology reporting in PRCC.

Expression of the Na+/K+-transporting ATPase gamma subunit FXYD2 in renal tumors

Chromophobe renal cell carcinoma (RCC) is a form of renal cancer that may be confused with other eosinophilic renal tumors, including oncocytoma, type 2 papillary RCC, and clear-cell RCC with eosinophilic features. There are currently no robust markers to distinguish these neoplasms. Chromophobe RCC and renal oncocytoma are presumably derived from the distal nephron. FXYD2 is a distal tubule regulator of the trimeric Na(+/)K(+)-transporting ATPase that is enriched in kidney tissue. In this study, we investigated the expression of FXYD2 in normal human kidney, 27 chromophobe RCCs, 30 oncocytomas, 15 clear-cell RCCs, and 11 papillary RCCs. Immunohistochemical staining for FXYD2 showed diffuse, strong immunoreactivity in the basolateral membrane of distal tubules of normal human kidney. Ninety-six percent (26/27) of chromophobe RCCs were immunoreactive for FXYD2 in a distinctly membranous pattern. Twenty-five of these tumors showed at least focal 2+ staining. In contrast, only 17% (5/30) of renal oncocytomas, 11% (2/15) of clear-cell RCCs, and 0% (0/11) of papillary RCCs displayed FXYD2 immunoreactivity. None of these cases showed ≥2+ FXYD2 staining. A subset of cases was confirmed as oncocytoma or chromophobe RCC using cytokeratin 7, colloidal iron, and interphase fluorescence in situ hybridization analysis of chromosomes 1, 2, 6, 10, and 17. Among this subset, 100% (7/7) of chromophobe RCCs were FXYD2 positive, whereas 17% (2/12) of oncocytomas were stained with FXYD2. The oncocytomas that stained with FXYD2 did so in a weak (1+), patchy manner. In contrast, chromophobe RCCs showed ≥2+ staining in 86% (6/7) of these tumors. For comparison, this subset was also stained for kidney-specific cadherin (Ksp-cadherin). Ksp-cadherin showed positive staining in 100% (7/7) of chromophobe RCCs and 33% (4/12) of oncocytomas. This is the first report demonstrating the potential utility of FXYD2 immunohistochemistry in the diagnosis of chromophobe RCC.

Validation of the pre-treatment neutrophil-lymphocyte ratio as a prognostic factor in a large European cohort of renal cell carcinoma patients

Background:

The neutrophil–lymphocyte ratio (NLR) has been proposed as an indicator of systemic inflammatory response. Several studies suggest a negative impact of increased NLR for patient's survival in different types of cancer. However, previous findings from small-scale studies revealed conflicting results about its prognostic significance with regard to different clinical end points in non-metastatic renal cell carcinoma (RCC) patients. Therefore, the aim of our study was the validation of the prognostic significance of NLR in a large cohort of RCC patients.

Methods:

Data from 678 consecutive non-metastatic clear cell RCC patients, operated between 2000 and 2010 at a single centre, were evaluated retrospectively. Cancer-specific, metastasis-free, as well as overall survival (OS) were assessed using the Kaplan–Meier method. To evaluate the independent prognostic significance of NLR, multivariate Cox regression models were applied for all three different end points. Influence of the NLR on the predictive accuracy of the Leibovich prognosis score was determined by Harrell's concordance index.

Results:

Multivariate analysis identified increased NLR as an independent prognostic factor for overall (hazard ratio (HR)=1.59, 95% confidence interval (CI)=1.10–2.31, P=0.014), but not for cancer-specific (HR=1.59, 95% CI=0.84–2.99, P=0.148), nor for metastasis-free survival (HR=1.39, 95% CI=0.85–2.28, P=0.184). The estimated concordance index was 0.79 using the Leibovich risk score and 0.81 when NLR was added.

Conclusion:

Regarding patients' OS, an increased NLR represented an independent risk factor, which might reflect a higher risk for severe cardiovascular and other comorbidities. Adding the NLR to well-established prognostic models such as the Leibovich prognosis score might improve their predictive ability.

Clear cell papillary renal cell carcinoma: a report of 15 cases including three cases of concurrent other-type renal cell carcinomas

Background

Clear cell papillary renal cell carcinoma (CCPRCC) is a recently established subtype of renal epithelial tumor. The aim of this study was to identify the diagnostic criteria of CCPRCC with an emphasis on immunohistochemical studies, and to report three cases with concurrent other-type renal cell carcinoma (RCC).

Methods

A total of 515 RCC patients that consecutively underwent surgical resection at Seoul National University Hospital from 1 January 2010 to 31 December 2011 were screened. Each case was reviewed based on the histologic features and was evaluated immunohistochemically.

Results

A total of 15 CCPRCCs were identified, which composed 2.9% of the total RCCs. The mean age was 52 years, and the average tumor size was 1.65 cm. All 15 cases showed low nuclear grade, no lymph node metastasis and no distant metastasis. The CCPRCCs showed variable architectural patterns including cystic, trabecular, papillary, and acinar. All of the cases showed moderate to intense immunoreactivity for cytokeratin 7 (CK7). CD10 was negative or showed focal weak positivity. Three cases had concurrent other-type RCC, including a clear cell RCC and an acquired cystic disease-associated RCC.

Conclusions

The strong CK7 and negative or focal weak CD10 expression will be useful for the diagnosis of CCPRCC.

Protein gene product 9.5 is diagnostically helpful in delineating high-grade renal cell cancer involving the renal medullary/sinus region from invasive urothelial cell carcinoma of the renal pelvis

The classification of poorly differentiated carcinomas involving the renal medullary/sinus region might be challenging on conventional histomorphologic grounds alone. However, delineation of high-grade renal cell carcinomas such as collecting duct (Bellini) carcinoma from urothelial cell carcinoma of the renal pelvis is critical, as it conveys important therapeutic implications. We assessed the so far neglected differential diagnostic role of protein gene product 9.5, a neuropeptide involved in intracellular proteolysis, in terms of differentiating invasive urothelial cell carcinomas of the renal pelvis from high-grade renal cell carcinomas infiltrating the renal medullary/sinus region. To this aim, 21 invasive urothelial cell carcinomas of the renal pelvis and 27 high-grade renal cell carcinomas (8 renal cell carcinomas with sarcomatoid dedifferentiation and 5 type 1 and 7 type 2 papillary renal cell carcinomas as well as 7 collecting duct carcinomas) were stained with antibodies directed against protein gene product 9.5, CD10, vimentin, CEA, p63, CK5/6, CK7, CK20, PAX2, PAX8, CD117 (c-Kit), AE1/3, α-methyl CoA racemase, actin, and desmin. Briefly, strong protein gene product 9.5 expression was observed in 6 (86%) of 7 collecting duct carcinomas, 8 (67%) of 12 papillary renal cell carcinomas, and 2 (25%) of 8 renal cell carcinomas with sarcomatoid dedifferentiation. Conversely, none of the 21 urothelial cell carcinomas investigated showed protein gene product 9.5 expression. Our findings suggest that protein gene product 9.5, particularly if used in conjunction with p63 and CK5/6, might be helpful in differentiating high-grade renal cell carcinomas from urothelial cell carcinomas of the renal pelvis, whereas its specificity with respect to the histologic subtyping of renal cell carcinomas seems to be low. However, because of the limited number of study cases enrolled in our investigation, our findings need to be validated in the future.

[Relevance of the clinical-pathological predictive factors in force in chromophobe renal cell cancer]

INTRODUCTION

The identification of new subtypes of renal cell carcinoma (RCC) has made it necessary to re-evaluate the current clinical and pathological predictive factors (stage, Fuhrman nuclear grade, necrosis, lymphovascular invasion [LVI] and sarcomatoid component) in these new subtypes. The chromophobe renal cell carcinoma (CRCC) is considered a less aggressive subtype of RCC. The purpose of this article is to evaluate the usefulness of current clinicopathologic predictors of RCC in our series of CRCC.

MATERIAL AND METHODS

We retrospectively reviewed the clinicopathologic features of 63 patients with CRCC treated with radical nephrectomy. The parameters analyzed were tumor extension with the TNM, grade according to Fuhrman classification, LVI, tumor necrosis, tumor thrombus, surgical margin status, and involvement of the collecting system. The results (disease recurrence) were evaluated by Cox regression model with univariate and multivariate analysis.

RESULTS

With a median follow up of 60.2 months (0.37-160.2), 8 (11%) patients had recurrence, with median time to recurrence of 31.7 months (5.37-124.33). In the univariate analysis, TNM extension (p=0.0001), Fuhrman grade III or IV (p=0.031), LVI (p=0.0001) and the presence of positive surgical margins (p=0.0001) were statistically significant variables for recurrence. In the multivariate analysis, only tumor stage was confirmed as an independent predictor of recurrence, pT1 versus pT2 (p=0.02, OR 0.27 95% CI 0.03-0.258) and pT2 versus higher stage (p=0.037, OR 0.173 95% CI 0.033-0.896).

CONCLUSIONS

The tumor stage predicts aggressiveness in the CCRC. The classification of Fuhrman nuclear grade is not useful for this histological subtype.

Potential role of genetic markers in the management of kidney cancer

CONTEXT

Kidney cancer is not a single entity but comprises a number of different types of cancer that occur in the kidney including renal cell tumours as the most common type. Four major renal cell tumour subtypes can be distinguished based on morphologic and genetic characteristics. To individualise therapy and to improve the prognosis in patients with renal cell tumours, accurate subtyping, definition of individual course of disease, and the prediction of therapy response are necessary.

OBJECTIVE

To discuss the potential role of genetic markers in the management of kidney cancer.

EVIDENCE ACQUISITION

A Medline search was conducted to identify original articles, review articles, and editorials addressing the role of genetic alterations in kidney cancer management. Keywords included kidney neoplasms, genetics, SNP, gene expression, miRNA, classification, diagnosis, drug therapy, prognosis, and therapy. The articles with the highest level of evidence were identified and critically reviewed. This review is the result of an interactive peer-reviewing process by an expert panel of co-authors.

EVIDENCE SYNTHESIS

Each subtype is characterised by specific genetic, epigenetic, and expression patterns that potentially can be used to subclassify renal cell tumours in cases of ambivalent histopathology. Molecular signatures and single alterations in primary tumours are associated with aggressiveness and prognosis. Germline polymorphisms in specific genes encoding for metabolizing enzymes, efflux transporters, and drug targets seem to be associated with toxicity and response in patients receiving targeted therapy.

CONCLUSIONS

Significant advances have been achieved in the molecular analysis of renal cancer. Validation of findings is greatly needed to implement genetic markers in the management of renal cancer. This should lead to improved diagnosis, prognosis, and personalised therapy in this heterogeneous disease.

Does preoperative platelet count and thrombocytosis play a prognostic role in patients undergoing nephrectomy for renal cell carcinoma? Results of a comprehensive retrospective series

PURPOSE

To evaluate the still controversially discussed prognostic role of preoperative platelet level (PPL) and thrombocytosis (TC) in patients who undergo surgery for renal cell carcinoma (RCC) based on the largest patient series reported to date.

METHODS

A total of 3,139 patients, who underwent radical or nephron-sparing nephrectomy at four centres, were subdivided based on a threshold for preoperative platelets of 400 × 10(9) cells/L. Univariate and multivariable Cox regression analyses were applied to determine the prognostic influence of PPL and TC on cancer-specific survival (CSS) for patients with localized and metastatic disease at presentation.

RESULTS

Group 1 (PPL ≤ 400/nl) and Group 2 (PPL > 400/nl) included 2,862 (91 %) and 277 patients (9 %), respectively. With a median follow-up (FU) of 69.5 months (IQR: 35-105), CSS of all patients after 5 years was 84.6 % in Group 1 versus 53.4 % in Group 2 (p < 0.001). At multivariable analysis, TC (HR:1.337; p = 0.007) and continuous PPL (HR:1.001; p = 0.002) independently predicted a decreased survival. However, integration of these parameters into multivariable models for the entire study group and for patients with localized tumours did only result in marginal improvement of the model quality (0.66 and 1.04 %, respectively). Interestingly, neither TC (p = 0.257) nor PPL (p = 0.132) significantly influenced survival in M1 patients.

CONCLUSIONS

Preoperative TC turned out an independent predictor for decreased CSS in patients undergoing surgery for localized RCC. However, significant improvement of multivariable models comprising standard clinical and pathological parameters by the inclusion of TC is not achieved. In metastatic disease, TC did not reveal an independent influence on CSS.

External validation of the preoperative Karakiewicz nomogram in a large multicentre series of patients with renal cell carcinoma

PURPOSE

To perform a formal external validation of the preoperative Karakiewicz nomogram (KN) for the prediction of cancer-specific survival (CSS) using a large series of surgically treated patients diagnosed with organ-confined or metastatic renal cell carcinoma (RCC).

METHODS

Patient population originated from a series of retrospectively gathered cases that underwent radical or partial nephrectomy between years 1995 and 2007 for suspicion of kidney cancer. The original Cox coefficients were used to generate the predicted risk of CSS at 1, 2, 5, and 10 years following surgery and compared to the observed risk of CSS in the current population. External validation was quantified using measures of predictive accuracy, defined as model discrimination and calibration.

RESULTS

A total of 3,374 patients were identified. Relative to the original development cohort, the current sample population had a larger proportion of patients with localized (40.0 vs. 26.3 %, P < 0.001) and non-metastatic (92.2 vs. 88.1 %, P = 0.03) disease at presentation. Model discrimination for the prediction of CSS was 87.8 % (95 % CI, 84.4-91.4) at 1 year, 87.0 % (95 % CI, 84.4-89.5) at 2 years, 84.7 % (95 % CI, 82.3-87.1) at 5 years, and 85.9 % (95 % CI, 83.2-88.6) at 10 years. The relationship between predicted and observed CSS risk was adequate in the calibration plot.

CONCLUSION

The use of the KN for the prediction of CSS in patients diagnosed with renal cell carcinoma was validated in the current study. In consequence, this tool may be recommended for routine clinical counseling in patients with various stages of RCC in the preoperative setting.

BAP1 loss defines a new class of renal cell carcinoma

The molecular pathogenesis of renal cell carcinoma (RCC) is poorly understood. Whole-genome and exome sequencing followed by innovative tumorgraft analyses (to accurately determine mutant allele ratios) identified several putative two-hit tumor suppressor genes including BAP1. BAP1, a nuclear deubiquitinase, is inactivated in 15% of clear-cell RCCs. BAP1 cofractionates with and binds to HCF-1 in tumorgrafts. Mutations disrupting the HCF-1 binding motif impair BAP1-mediated suppression of cell proliferation, but not H2AK119ub1 deubiquitination. BAP1 loss sensitizes RCC cells in vitro to genotoxic stress. Interestingly, BAP1 and PBRM1 mutations anticorrelate in tumors (P=3×10⁻⁵), and combined loss of BAP1 and PBRM1 in a few RCCs was associated with rhabdoid features (q=0.0007). BAP1 and PBRM1 regulate seemingly different gene expression programs, and BAP1 loss was associated with high tumor grade (q=0.0005). Our results establish the foundation for an integrated pathological and molecular genetic classification of RCC, paving the way for subtype-specific treatments exploiting genetic vulnerabilities.

Renal cell carcinoma with clear cell and papillary features

CONTEXT

The diagnosis of primary renal cell carcinomas (RCCs) with both papillary architecture and cells with clear cytoplasm can be diagnostically challenging for practicing pathologists. The 4 main neoplasms in the differential diagnosis are clear cell RCC, papillary RCC, clear cell papillary RCC, and Xp11 translocation RCC. Accurate diagnosis has both prognostic and therapeutic implications.

OBJECTIVE

To highlight the helpful cytomorphologic, immunohistochemical, and cytogenetic features of each of these entities to enable reproducible classification.

DATA SOURCES

Published peer-reviewed literature was reviewed, accompanied by the authors' personal experiences.

CONCLUSIONS

Key morphologic clues and a focused immunohistochemical panel, including CK7, α-methylacyl coenzyme A racemase (AMACR), TFE3, cathepsin K, and carbonic anhydrase IX (CAIX), now allow most resected RCCs with papillary architecture and clear cells to be accurately classified. In other cases, cytogenetic and molecular findings can establish the diagnosis. Despite these tools, some RCCs with papillary architecture and clear cells do not fit into any of the described entities and currently remain unclassified.

Unclassified renal cell carcinoma: a report of 56 cases

What's known on the subject? and What does the study add? Unclassified RCC represents 0.7-5.7% of renal tumours. Limited reported data from two series suggests that unclassified RCC is an aggressive form of RCC, mainly because most cases are at an advanced stage at presentation, but overall and cancer-specific survival were not significantly different between unclassified and clear-cell RCC in an additional series of 38 patients. Our study of 56 cases of unclassified RCC describes the pathological features that can be applied to predict prognosis on a daily basis. In particular nuclear grade, TNM classification, tumour coagulative necrosis, tumour size, microvascular invasion and 2004 WHO histotype are independent predictors of disease-free and cancer-specific survival.

OBJECTIVE

To evaluate the clinicopathological features and outcomes of 56 patients with unclassified renal cell carcinoma (RCC) meeting 2004 World Health Organization diagnostic criteria.

PATIENTS AND METHODS

Urological pathology files of the participating institutions were reviewed and cases of unclassified RCC that met the inclusion criteria were retrieved. Nuclear grade, pT status, tumour size, regional lymph node involvement, distant metastases, coagulative tumour necrosis, mucin and sarcomatoid differentiation were evaluated in radical nephrectomy or nephron-sparing specimens. Significant factors in univariate analysis were then assessed by a multivariate analysis of independent prognostic factors using Cox proportional hazard regression analysis.

RESULTS

Fifty-six cases met the histological criteria for unclassified RCC. Thirty-four (61%) cases were categorized as unrecognizable cell type (mean overall survival 47 months; median 36 months), 20 (36%) as composites of recognized types (mean overall survival 36 months; median 26 months), and two (4%) (mean survival 16 months; median 16 months) as pure sarcomatoid morphology without recognizable epithelial elements. Cox multivariate analysis showed nuclear grade (P = 0.020), stage (P < 0.001), tumour coagulative necrosis (P = 0.018), tumour size (P < 0.001), microvascular invasion (P < 0.001) and tumour histotype (P = 0.028) to be independent predictors of disease-free survival, with tumour size being the most significant (hazard ratio [HR] 9.068, 95% confidence interval [CI] 3.231-25.453). Nuclear grade (P = 0.026), stage (P < 0.001), tumour coagulative necrosis (P < 0.001), tumour size (P = 0.044), microvascular invasion (P < 0.001), tumour recurrence after surgery (P < 0.001) and tumour histotype (P = 0.056) were independent predictors of cancer-specific survival, with tumour recurrence after surgery being the most significant (HR 14.713, 95% CI 5.329-40.622).

CONCLUSION

The prognosis of patients with unclassified RCC seems to be related to clinicopathological features known to be relevant in common forms of RCC.