Grading Clear Cell Renal Cell Carcinoma Grade Using Diffusion Relaxation Correlated MR Spectroscopic Imaging

BACKGROUND

Clear cell renal cell carcinoma (ccRCC) is the most common subtype of RCC, and accurate grading is crucial for prognosis and treatment selection. Biopsy is the reference standard for grading, but MRI methods can improve and complement the grading procedure.

PURPOSE

Assess the performance of diffusion relaxation correlation spectroscopic imaging (DR-CSI) in grading ccRCC.

STUDY TYPE

Prospective.

SUBJECTS

79 patients (age: 58.1 +/- 11.5 years; 55 male) with ccRCC confirmed by histopathology (grade 1, 7; grade 2, 45; grade 3, 18; grade 4, 9) following surgery.

FIELD STRENGTH/SEQUENCE

3.0 T MRI scanner. DR-CSI with a diffusion-weighted echo-planar imaging sequence and T2-mapping with a multi-echo spin echo sequence.

ASSESSMENT

DR-CSI results were analyzed for the solid tumor regions of interest using spectrum segmentation with five sub-region volume fraction metrics (VA , VB , VC , VD , and VE ). The regulations for spectrum segmentation were determined based on the D-T2 spectra of distinct macro-components. Tumor size, voxel-wise T2, and apparent diffusion coefficient (ADC) values were obtained. Histopathology assessed tumor grade (G1-G4) for each case.

STATISTICAL TESTS

One-way ANOVA or Kruskal-Wallis test, Spearman's correlation (coefficient, rho), multivariable logistic regression analysis, receiver operating characteristic curve analysis, and DeLong's test. Significance criteria: P < 0.05.

RESULTS

Significant differences were found in ADC, T2, DR-CSI VB , and VD among the ccRCC grades. Correlations were found for ccRCC grade to tumor size (rho = 0.419), age (rho = 0.253), VB (rho = 0.553) and VD (rho = -0.378). AUC of VB was slightly larger than ADC in distinguishing low-grade (G1-G2) from high-grade (G3-G4) ccRCC (0.801 vs. 0.762, P = 0.406) and G1 from G2 to G4 (0.796 vs. 0.647, P = 0.175), although not significant. Combining VB , VD , and VE had better diagnostic performance than combining ADC and T2 for differentiating G1 from G2-G4 (AUC: 0.814 vs 0.643).

DATA CONCLUSION

DR-CSI parameters are correlated with ccRCC grades, and may help to differentiate ccRCC grades.

EVIDENCE LEVEL

2 TECHNICAL EFFICACY STAGE: 2.

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

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

Pathological diagnostic nomograms for predicting malignant histology and unfavorable pathology in patients with endophytic renal tumor

Purpose

To develop and validate nomograms for pre-treatment prediction of malignant histology (MH) and unfavorable pathology (UP) in patients with endophytic renal tumors (ERTs).

Methods

We retrospectively reviewed the clinical information of 3245 patients with ERTs accepted surgical treatment in our center. Eventually, 333 eligible patients were included and randomly enrolled into training and testing sets in a ratio of 7:3. We performed univariable and multivariable logistic regression analyses to determine the independent risk factors of MH and UP in the training set and developed the pathological diagnostic models of MH and UP. The optimal model was used to construct a nomogram for MH and UP. The area under the receiver operating characteristics (ROC) curves (AUC), calibration curves and decision curve analyses (DCA) were used to evaluate the predictive performance of models.

Results

Overall, 172 patients with MH and 50 patients with UP were enrolled in the training set; and 74 patients with MH and 21 patients with UP were enrolled in the validation set. Sex, neutrophil-to-lymphocyte ratio (NLR), R score, N score and R.E.N.A.L. score were the independent predictors of MH; and BMI, NLR, tumor size and R score were the independent predictors of UP. Single-variable and multiple-variable models were constructed based on these independent predictors. Among these predictive models, the malignant histology-risk nomogram consisted of sex, NLR, R score and N score and the unfavorable pathology-risk nomogram consisted of BMI, NLR and R score performed an optimal predictive performance, which reflected in the highest AUC (0.842 and 0.808, respectively), the favorable calibration curves and the best clinical net benefit. In addition, if demographic characteristics and laboratory tests were excluded from the nomograms, only the components of the R.E.N.A.L. Nephrometry Score system were included to predict MH and UP, the AUC decreased to 0.781 and 0.660, respectively (P=0.001 and 0.013, respectively).

Conclusion

In our study, the pathological diagnostic models for predicting malignant and aggressive histological features for patients with ERTs showed outstanding predictive performance and convenience. The use of the models can greatly assist urologists in individualizing the management of their patients.

Partial Nephrectomy Versus Radical Nephrectomy for Endophytic Renal Tumors: Comparison of Operative, Functional, and Oncological Outcomes by Propensity Score Matching Analysis

Purpose

The study aimed to compare operative, functional, and oncological outcomes between partial nephrectomy (PN) and radical nephrectomy (RN) for entophytic renal tumors (ERTs) by propensity score matching (PSM) analysis.

Methods

A total of 228 patients with ERTs who underwent PN or RN between August 2014 and December 2021 were assessed. A PSM in a 1:1 ratio was conducted to balance the differences between groups. Perioperative characteristics, renal functional, and oncological outcomes were compared between groups. Univariate and multivariate logistic and Cox proportional hazard regression analyses were used to determine the predictors of functional and survival outcomes.

Results

After PSM, 136 cases were matched to the PN group (n = 68) and the RN group (n = 68). Patients who underwent RN had shorter OT, less EBL, and lower high-grade complications (all p <0.05) relative to those who underwent PN. However, better perseveration of renal function was observed in the PN group, which was reflected in 48-h postoperative AKI (44.1% vs. 70.6%, p = 0.002), 1-year postoperative 90% eGFR preservation (45.6% vs. 22.1%, p = 0.004), and new-onset CKD Stage ≥III at last follow-up (2.9% vs. 29.4%, p <0.001). RN was the independent factor of short-term (OR, 2.812; 95% CI, 1.369–5.778; p = 0.005) and long-term renal function decline (OR, 10.242; 95% CI, 2.175–48.240; p = 0.003). Furthermore, PN resulted in a better OS and similar PFS and CSS as compared to RN (p = 0.042, 0.15, and 0.21, respectively). RN (OR, 7.361; 95% CI, 1.143–47.423; p = 0.036) and pT3 stage (OR, 4.241; 95% CI, 1.079–16.664; p = 0.039) were independent predictors of overall mortality.

Conclusion

Among patients with ERTs, although the PN group showed a higher incidence of high-grade complications than RN, when technically feasible and with experienced surgeons, PN is recommended for better preservation of renal function, longer OS, and similar oncological outcomes.

Modified cancer TNM classification for localized renal cell carcinoma based on the prognostic analysis of 3748 cases from a single center

The optimal cutoff point for evaluating the prognosis of localized renal cell carcinoma (LRCC) remains unclear. This study aimed to verify the efficacy of tumor diameter in the 2010 American Joint Committee on Cancer (AJCC) TNM staging system and contribute to the modification of TNM staging on the prognosis of this disease. A total of 3748 patients with LRCC were enrolled and grouped according to the 2010 AJCC TNM staging system. COX analysis was used to stratify the prognosis. The optimal cutoff point of the tumor diameter in the T1 and T2 prognosis was explored. There were 3330 (88.9%) patients in stage T1 and 418 (11.1%) in stage T2. The cancer-specific mortality rate was 2.7% (100/3748). The mean follow-up was 49.8 months. A tumor diameter of 7 cm can determine the prognosis of patients at stages T1 and T2; however, 4.5 cm and 11 cm as the cutoff points for T1 and T2 sub-classification of patients with LRCC might show better recognition ability than 4 cm and 10 cm, respectively. The 2010 AJCC TNM stage can predict the prognosis of LRCC in stages T1 and T2. In addition, a tumor diameter of 4.5 cm and 11 cm might be the optimal cutoff points for the sub-classification of stages T1 and T2.

Clinical Outcomes of Robotic Assisted Partial Nephrectomy for Pathologic T3a Renal Masses with Venous Tumor Thrombus

OBJECTIVE

To evaluate the safety, efficacy, and early oncologic outcomes of pT3a renal cell carcinoma (RCC) with venous involvement treated with robotic partial nephrectomy (RPN), given that experience and outcomes in this group is limited.

METHODS

A retrospective chart review of patients undergoing RPN from 9/2009-7/2020 was performed. Outcomes were captured from patients with pathologic T3a disease with vein involvement. Clinical characteristics were analyzed using SPSS (IBM, Armonk, NY). Local recurrence-free survival (LRFS) and metastasis-free survival (MFS) at 2 years were calculated from Kaplan-Meier survival curves.

RESULTS

For 45 included patients, mean operative and warm ischemia times were 199.6 min ± 47.3 and 30.5 min ± 10.5, with mean estimated blood loss of 324.9 cc ±209.5. Rates of transfusion, embolization, re-admission, and re-operation at 30 days were 8.9% (4/45), 2.2% (1/45), 11.1% (5/45), and 6.7% (3/45; cystoscopic stent placement), respectively. All tumors were malignant on pathology, with clear cell RCC being the most common (91.0%, n=41). The positive margin rate was 6.7% (n=3). Local recurrence occurred in 4.4% (n=2) at a mean time of 5.2 months ± 2.3. Four patients (8.9%) progressed to metastatic disease at a mean of 22.2 months ± 23.0. At 2 years, LRFS was 95.4% and MFS was 95.3%.

CONCLUSIONS

We present the largest known series of patients RPN for pT3a renal masses with venous tumor involvement. We found it both feasible and safe in the appropriate hands. Short term oncologic outcomes for these patients appear more favorable than historic literature suggested. SOURCES OF FUNDING: none.

Update on the Role of Imaging in Clinical Staging and Restaging of Renal Cell Carcinoma Based on the AJCC 8th Edition, From the AJR Special Series on Cancer Staging

This article reviews the essential role of imaging in clinical staging and restaging of renal cell carcinoma (RCC). To completely characterize and stage an indeterminate renal mass, renal CT or MRI without and with IV contrast administration is recommended. The critical items for initial clinical staging of an indeterminate renal mass or of a known RCC according to the TNM staging system are tumor size, renal sinus fat invasion, urinary collecting system invasion, perinephric fat invasion, venous invasion, adrenal gland invasion, invasion of the perirenal (Gerota) fascia, invasion into other adjacent organs, the presence of enlarged or pathologic regional (retroperitoneal) lymph nodes, and the presence of distant metastatic disease. Larger tumor size is associated with higher stage disease and invasiveness, lymph node spread, and distant metastatic disease. Imaging practice guidelines for clinical staging of RCC, as well as the role of renal mass biopsy, are highlighted. Specific findings associated with response of advanced cancer to antiangiogenic therapy and immunotherapy are discussed, as well as limitations of changes in tumor size after targeted therapy. The accurate clinical staging and restaging of RCC using renal CT or MRI provides important prognostic information and helps guide the optimal management of patients with RCC.

Trends in the surgical management of renal cell carcinoma in a contemporary tertiary care setting

Background

In the last three eras, the incidence of renal cell carcinoma (RCC) has increased, due to increased radiological studies. The expected 5-year survival rate has become better, associated with the identification of small size renal masses. However, this survival improvement may be secondary to improved surgical techniques and medical therapies for these malignancies.

Objectives

The objective was to report the trends of clinical presentation, peri-operative, oncological outcomes, and surgical management trends for RCCs over the period.

Methods

After Institutional Review Board approval, a retrospective study for adult patients was conducted, who presented with renal mass and were managed between 2008 and 2019. Variables, including demographics, perioperative and pathological outcomes analyzed using descriptive statistics for continuous variables reported as mean ± standard deviation and categorical variables values compared by Chi-square test. Survival Analysis calculated using the Kaplan-Meier method. The level of significance is set at P-value < 0.05.

Results

A total of 588 patients underwent surgical treatment for kidney cancer from January 2008 to January 2019. 237 (40.30%) were females and 351 (59.69%) males. The clinical presentation was higher as an incidental diagnosis of 58.67%. 71.25% of patients were from outside Riyadh city. Pathology was mostly clear cell RCC 61.22% and grade 2 (57.48%). Tumor size, surgery time, and length of hospital stay showed a significant difference between the three periods (both P > 0.05). Robotic surgery performed more than open (P < 0.0001). There was no significant difference in the survival time, when compared to patients by the regions and when compared by the primary tumors (Log-Rank P = 0.4821). Patients from the Riyadh region (median = 54.0) had a significantly higher recurrence time (Log-Rank P < 0.0001).

Conclusion

There was a rising trend in the incidence of RCC associated with comorbidities and incidental diagnosis. In our study period we found increase in the trend of minimal invasive approach. The size of the tumor, blood loss and operative time decreases over the period of time. The Robotic assisted nephrectomy approach has become increased over the period of time duration in present study.

Correlation between CT and anatomopathological staging of kidney cancer

Our Moroccan context is experiencing an increase in the frequency of renal tumors. This trend can be explained by the generalization of the use of imaging, in particular abdominal ultrasound, which has become almost systematic among general practitioners (Godley and Ataga, 2000 [1]). The specificity of kidney cancer is anatomopathological heterogenicity: histological type, nuclear grade, tumor stage, these elements constitute the most important prognostic factors. Renal biopsy appears to be a safe and reliable solution with a low risk of tumor seeding and complications, however it cannot provide all the detailed histological information needed. Hence the interest in the abdominal scanner. The abdominal scanner is the reference examination for the evaluation of renal tumors, it diagnoses the tumor, specifies these characteristics, it assesses the loco regional, venous extension. The objective of our study is to correlate pathological and CT findings of 70 kidney cancer in order to determine the reliability of CT in kidney cancer and its extension.

Elective partial and radical nephrectomy in patients with renal cell carcinoma in CT1B stadium

Background/Aim. In renal cell carcinoma (RCC) the choice of surgical technique, radical (RN) or partial nephrectomy (PN) is still centre dependant because there still are no absolute recommendations for this approach. This study aims to analyze the oncological aspects, time until recurrent disease appears and cancer-specific survival in patients with RCC in T1bN0?0 depending on the type of surgical procedure partial or radical nephrectomy. Methods. A clinical observational study of a series of cases was conducted that analyzed data of 154 patients operated in our institution with a mean follow up a period not less than five years. The inclusion criteria included: renal tumours 4-7 cm, histopathological confirmation of RCC, absence of metastasis and normal serum creatinine. Exclusion criteria included: the presence of other malignancies, solitary functional kidney or comorbidities that can compromise renal function, bilateral tumours or unilateral multiple tumours. Results. The study analyzed data of 154 patients, 97 radical nephrectomies and 57 patients that underwent partial nephrectomy. Analyzing cancer-specific survival in four patients with RN there was a disease advancement that led to a lethal outcome, one PN patient died as a result of local relapse and distant metastasis. Conclusion. Based on our results PN is a good and safe treatment option for patients with RCC in T1b stadium. Partial nephrectomy offers a similar tumour control and better cancer-specific survival.

Histologic Heterogeneity of Extirpated Renal Cell Carcinoma Specimens: Implications for Renal Mass Biopsy

Pathologic characteristics of extirpated renal cell carcinoma (RCC) specimens <7 cm were reviewed to get better information on technical nuances of renal mass biopsy (RMB). Specimens were stratified according to tumor stage, nuclear grade, size, histology, presence of lymphovascular invasion (LVI), necrosis, and sarcomatoid features. When considering pT1 (0–7 cm) tumors, pT1b (4–7 cm) RCC masses were more likely to have necrosis (43% vs 16%, P < 0.001), LVI (6% vs 2%, P = 0.024), high-grade nuclear elements (29% vs 17%, P < 0.001), and sarcomatoid features (2% vs 0%, P = 0.006) compared with pT1a (0–4 cm) tumors. Additionally, pT3a tumors were more highly associated with necrosis (P = 0.005), LVI, sarcomatoid features, and high-grade disease (P for all < 0.001) when compared to pT1 masses. For masses <4 cm, pT3a cancers were more likely to demonstrate necrosis (38% vs 16%, P < 0.001), LVI (22% vs 2%, P < 0.001), high-grade nuclear elements (45% vs 17%, P < 0.001), and sarcomatoid features (12% vs 0%, P < 0.001) compared to pT1a tumors. Similarly, for masses 4–7 cm, pathologic T3a tumors were significantly more likely to have sarcomatoid features (12% vs 2%, P = 0.006) and LVI (22% vs 6%, P = 0.003) compared to pT1b tumors. In summary, pT3a tumors and those RCC masses >4 cm exhibit considerable histologic heterogeneity and may harbor elements that are not easily appreciated with limited renal sampling. Therefore, if RMB is considered for renal masses greater than 4 cm or those that abut sinus fat, a multi-quadrant biopsy approach is necessary to ensure adequate sampling and characterization of the mass.

The anti-inflammatory protein MCPIP1 inhibits the development of ccRCC by maintaining high levels of tumour suppressors

Clear cell renal cell carcinoma (ccRCC) is the most common subtype of kidney cancer. It is highly vascularized and largely resistant to traditional chemo- and radiotherapy. Decreases in tumour suppressors and low levels of the anti-inflammatory Monocyte Chemoattractant Protein-Induced Protein 1 (MCPIP1) play important roles in the development and progression of ccRCC. MCPIP1, also called Regnase-1, possesses endonuclease activity and degrades the mRNA of proinflammatory cytokines such as IL-6, IL-1β, IL-12 and IL-2. We previously showed that the level of MCPIP1 decreases with ccRCC progression. In this study, we explored the role of MCPIP1 in regulating the levels of tumour suppressors. We found low levels of the suppressors PTEN, RECK and TIMP3 and high levels of MMPs in patients with ccRCC who had already been shown to have low MCPIP1 expression. We demonstrated that MCPIP1 regulates the expression levels of PTEN, RECK and TIMP3 in ccRCC cell lines as well as in vivo models of ccRCC. MCPIP1 overexpression increased the expression of tumour suppressors. Moreover, we observed that the RNase activity of MCPIP1 is responsible for the modulation of apoptosis and activation of prometastatic signalling pathways. Furthermore, we found a negative correlation between high levels of IL6, a direct target of MCPIP1 RNase activity, and TIMP3 in patients, indicating that MCPIP1 and TIMP3 might collectively cause the high levels of IL6 in ccRCC patients. Taken together, our results show the importance of MCPIP1 in regulating the level of tumour suppressors and, consequently, in ccRCC development and progression.

Obesity: An independent protective factor for localized renal cell carcinoma in a systemic inflammation state

Objectives

To explore the prognostic value of obesity (measured by BMI) on RCC in a systemic inflammation state.

Patients and Methods

Clinicopathological and hematological data of 540 surgically treated Chinese localized RCC patients between 2005 and 2010 were retrospectively collected. Found by receiver operating characteristic (ROC) curve for cancer-specific survival (CSS), the optimal cutoff values of neutrophil-lymphocyte ratio (NLR, an indicator of systemic inflammation state) and BMI were 2.12 and 23.32, respectively. Survival curves were drawn using Kaplan-Meier method. Univariate and multivariate Cox regression analyses were used to evaluate the prognostic value of BMI in localized RCC patients with different NLR.

Results

Overall, 36 patients died with a median follow-up of 70 months. Median overall survival (OS) was 66 months and the 5-year OS rate was 92.7%. In the multivariate analysis of total patients, higher BMI was an independent protective factor for CSS in total patients (p=0.048). While in systemic inflammation subgroup (high NLR subgroup) patients, higher BMI (obesity) turned out to be an independent protective factor for both CSS (p=0.025) and RFS (p=0.048).

Conclusion

In localized RCC patients, obesity was an independent protective factor for CSS and RFS in a systemic inflammation state.

Predictive models composed by radiomic features extracted from multi-detector computed tomography images for predicting low- and high- grade clear cell renal cell carcinoma: A STARD-compliant article

To evaluate the values of conventional image features (CIFs) and radiomic features (RFs) extracted from multi-detector computed tomography (MDCT) images for predicting low- and high-grade clear cell renal cell carcinoma (ccRCC).Two hundred twenty-seven patients with ccRCC were retrospectively recruited. Five hundred seventy features including 14 CIFs and 556 RFs were extracted from MDCT images of each ccRCC. The CIFs were extracted manually and RFs by the free software-MaZda. Least absolute shrinkage and selection operator (Lasso) was applied to shrink the high-dimensional data set and select the features. Five predictive models for predicting low- and high-grade ccRCC were constructed by the selected CIFs and RFs. The 5 models were as follows: model of minimum mean squared error (minMSE) of CIFs (CIF-minMSE), minMSE of cortico-medullary phase (CMP) of kidney (CMP-minMSE), minMSE of parenchyma phase (PP) of kidney (PP-minMSE), the combined model of CIF-minMSE and CMP-minMSE (CIF-CMP-minMSE), and the combined model of CIF-minMSE and PP-minMSE (CIF-PP-minMSE). The Lasso regression equation of each model was constructed, and the predictive values were calculated. The receiver operating characteristic (ROC) curves of predictive values of the 5 models were drawn by SPSS19.0, and the areas under the curves (AUCs) were calculated.According to Lasso regression, 12, 19 and 10 features were respectively selected from the CIFs, RFs of CMP image and that of PP images to construct the 5 predictive models. The models ordered by their AUCs from large to small were CIF-CMP-minMSE (AUC: 0.986), CIF-PP-minMSE (AUC: 0.981), CIF-minMSE (AUC: 0.980), CMP-minMSE (AUC: 0.975), and PP-minMSE (AUC: 0.963). The maximum diameter of the largest axial section of ccRCC had a maximum weight in predicting the grade of ccRCC among all the features, and its cutoff value was 6.15 cm with a sensitivity of 0.901, a specificity of 0.963, and an AUC of 0.975.When combined with CIFs, RFs extracted from MDCT images contributed to the larger AUC of the predictive model, but were less valuable than CIFs when used alone. The CIF-CMP-minMSE was the optimal predictive model. The maximum diameter of the largest axial section of ccRCC had the largest weight in all features.

The utility of ADC measurement techniques for differentiation of low- and high-grade clear cell RCC

Purpose

To evaluate the diffusion properties of clear cell renal cell carcinoma (ccRCC) on magnetic resonance imaging (MRI) concerning their Fuhrman nuclear grades and sizes, and to compare the diagnostic performance of two ROI placement techniques for apparent diffusion coefficient (ADC) measurement (entire mass vs. only the darkest region of the mass).

Material and methods

Fifty-one ccRCC were enrolled in the study and grouped into low-grade ccRCC (Fuhrman grade 1 and 2, n = 37) and high-grade ccRCC (Fuhrman grade 3 and 4, n = 14). Selective ADC (Sel-ADC) measurement was performed by placing a circular ROI that included the darkest region of the tumour on ADC map images. Extensive ADC (Ext-ADC) measurement was performed by drawing an ROI that covered the entire tumour.

Results

The Sel-ADC value was lower in high-grade ccRCC (p = 0.019), whereas the Ext-ADC value did not show a statistically significant difference (p = 0.42). Sel-ADC value of a ≤ 1.405 mm²/s has a sensitivity, specificity, positive predictive value, negative predictive value, and accuracy value of 78.6, 72.2, 73.87, 77.13, and 75.4, respectively, to differentiate high-grade from low-grade ccRCC. The size and Fuhrman grade of the ccRCC were inversely correlated with the Sel-ADC value; however, the correlations were weak (r = -0.322, p = 0.021 and r = -0.376, p = 0.006, respectively). There was no difference between ADC values of small (≤ 4 cm) and large (> 4 cm) ccRCCs.

Conclusions

The ADC value of the darkest region in solid part of the ccRCC may play a role in predicting the nuclear grade of ccRCC.

Differentiating solid, non-macroscopic fat containing, enhancing renal masses using fast Fourier transform analysis of multiphase CT

OBJECTIVE

To test the feasibility of two-dimensional fast Fourier transforms (FFT)-based imaging metrics in differentiating solid, non-macroscopic fat containing, enhancing renal masses using contrast-enhanced CT images. We quantify image-based intratumoral textural variations (indicator of tumor heterogeneity) using frequency-based (FFT) imaging metrics.

METHODS

In this Institutional Review Board approved, Health Insurance Portability and Accountability Act -compliant, retrospective case-control study, we evaluated 156 patients with predominantly solid, non-macroscopic fat containing, enhancing renal masses identified between June 2009 and June 2016. 110 cases (70%) were malignant RCC, including clear cell, papillary and chromophobe subtypes and, 46 cases (30%) were benign renal masses: oncocytoma and lipid-poor angiomyolipoma. Whole lesions were manually segmented using Synapse 3D (Fujifilm, CT) and co-registered from the multiphase CT acquisitions for each tumor. Pathological diagnosis of all tumors was obtained following surgical resection. Matlab function, FFT2 was used to perform the image to frequency transformation.

RESULTS

A Wilcoxon rank sum test showed that FFT-based metrics were significantly (p < 0.005) different between 1. benign vs malignant renal masses, 2. oncocytoma vs clear cell renal cell carcinoma and 3. oncocytoma vs lipid-poor angiomyolipoma. Receiver operator characteristics analysis revealed reasonable discrimination (area under the curve >0.7, p < 0.05) within these three groups of comparisons.

CONCLUSION

In combination with other metrics, FFT-metrics may improve patient management and potentially help differentiate other renal tumors. Advances in knowledge: We report for the first time that FFT-based metrics can differentiate between some solid, non-macroscopic fat containing, enhancing renal masses using their contrast-enhanced CT data.

Prognostic significance of hypoxia inducible factor-1α expression in patients with clear cell renal cell carcinoma

The prognostic significance of hypoxia inducible factor-1α (HIF-1α) expression in tumors and the levels of preoperative hemoglobin in clear cell renal cell carcinoma (ccRCC), with or without concomitant chronic obstructive pulmonary disease (COPD), was investigated. A total of 128 patients with ccRCC who underwent surgery were analyzed using retrospective methods. Overall survival (OS) and progression free survival (PFS) were analyzed with clinicopathological variables, including preoperative hemoglobin levels, COPD and the levels of HIF‑1α expression, by Kaplan‑Meier survival analysis. Levels of HIF‑1α expression were detected by immunohistochemistry and the multivariate analysis was performed by proportional hazards regression. High levels of HIF‑1α expression were associated with a higher pathological stage and histological grade in patients with ccRCC (P<0.05). The median OS and PFS of patients with concomitant COPD were shorter compared with patients without COPD (P<0.05). The levels of serum hemoglobin, HIF‑1α expression and COPD diagnosis were all identified as independent prognostic variables for the OS and PFS of patients with ccRCC.

Pathological nature of renal tumors - does size matter?

INTRODUCTION

We examined the relationship between the size and nature of renal masses in term of malignant potential, histological grading, pathological staging and presence of necrosis and sarcomatoid changes.

MATERIALS AND METHODS

Retrospectively, we reviewed 323 consecutive nephrectomies between 2000 and 2010. Final pathology was correlated with tumour size. The renal tumours were stratified into three groups according to the largest diameter, defined as 4 cm or smaller, greater than 4 cm to 7 cm, and greater than 7 cm. We recorded the proportion of benign tumours, tumour grade and stage, presence of necrosis and sarcomatoid change.

RESULTS

Small renal masses ≤4 cm (SRMs) were more likely to be localised to the kidney (90%) and of lower histological grade (75%). The proportion of benign tumours in SRMs (15%) was higher than other two groups with the majority of benign tumours being oncocytomas. There was a statistically significant trend with greater necrosis and sarcomatoid change for the large size group.

CONCLUSIONS

SRMs are likely to be low grade and organ confined with little or no adverse pathological features. There is increased likelihood of benignity in SRTs with the majority of benign tumours being oncocytomas.

Differentiation of low- and high-grade clear cell renal cell carcinoma: Tumor size versus CT perfusion parameters

PURPOSE

To compare the utility of tumor size and CT perfusion parameters for differentiation of low- and high-grade clear cell renal cell carcinoma (RCC).

MATERIALS AND METHODS

Tumor size, Equivalent blood volume (Equiv BV), permeability surface-area product (PS), blood flow (BF), and Fuhrman pathological grading of clear cell RCC were retrospectively analyzed.

RESULTS

High-grade clear cell RCC had significantly higher tumor size and lower PS than low grade. Tumor size positively correlated with Fuhrman grade, but PS negatively did.

CONCLUSIONS

Tumor size and PS were significantly independent indexes for differentiating high-grade from low-grade clear cell RCC.

TIMP-1 as well as Microvessel Invasion and High Nuclear Grade Is a Significant Determinant Factor for Extension of Tumor Diameter in Localized RCC

Objectives. To clarify what kind of pathological factor is necessary for the extension of tumor diameter in localized RCC, we studied localized RCC patients. Methods. We retrospectively reviewed medical records of 237 RCC patients in our institute who underwent nephrectomy. We performed immune histological analysis of MMP-2, MMP-9, TIMP-1, TIMP-2, and MT-MMP-1 for all samples. Results. Among the clinicopathological factors, multivariate analysis revealed nuclear grade; TIMP-2 and MT-MMP-1 were independent prognostic factors of localized RCC (risk ratio 1.50, p = 0.037, risk ratio 1.12, p = 0.008, and risk ratio 1.84, p = 0.045, resp.). By the multiple logistic regression analysis among pT1a versus pT1b, TIMP-1 was an independent factor (risk ratio 3.30, p = 0.010) whereas all pT1 versus pT2a and all pT1 + pT2a versus pT2b high nuclear grade (risk ratio 5.15, p = 0.0015) and Micro vessel invasion (MVI, risk ratio 3.08, p = 0.002) were independent factors. For all pT1 + pT2a versus pT2b, nuclear grade (risk ratio 3.39, p = 0.020) and MVI (risk ratio 2.91, p = 0.018) were independent factors. Conclusion. Higher expression of TIMP-1 is necessary for advancement tumor diameter from pT1a to pT1b, and a process of tumor diameter extension beyond pT1 and pT2a category needs presence of MVI and high nuclear grade.

Intratumor heterogeneity in clear cell renal cell carcinoma: a review for the practicing pathologist

Intertumor heterogeneity, defined as the spectrum of morphological differences found in similar tumors in different patients, is a well-known event for pathologists. However, recent molecular studies have pointed to intratumor heterogeneity as one of the most important issues in human neoplasia in the next years. Clear cell renal cell carcinoma is an example of an intrinsically heterogeneous neoplasm, and some of the most salient advances in the knowledge of intratumor heterogeneity have been developed on it. This review intends to analyze this phenomenon in this tumor from the practicing pathologist's point of view. A careful study of the surgical specimen and an exhaustive tumor sampling are mandatory to keep relevant information. Currently accepted protocols designed for renal tumor sampling may be insufficient. As a result, a different approach to tumor sampling is advisable to ascertain that intratumor heterogeneity, if present, will be well represented in the selected material.

Ring Suture Technique in Retroperitoneal Laparoscopic Partial Nephrectomy for Hilar Cancer: A New Renorrhaphy Technique

BACKGROUND AND PURPOSE

To evaluate the safety and efficacy of a ring suture technique during retroperitoneal laparoscopic partial nephrectomy (RLPN) for management of renal cell carcinoma (RCC) in the renal hilum.

PATIENTS AND METHODS

Data for patients with renal hilar cancer who underwent RLPN from January 2010 to March 2015 were collected. All surgeries involved the ring suture technique, following the same procedure: the renal artery was dissected and clamped, the tumor was enucleated from the kidney, defects of the vascular and collecting system were repaired, and then the edge of the renal parenchyma was sutured continuously along the border. Finally, the renal artery clamp was removed, and any injury of the vascular system was repaired if necessary. We retrospectively analyzed renal ischemic time, blood loss, and postoperative complications.

RESULTS

Among the 17 patients, 11 were male (median age 61 years, range 42-71 years). Mean tumor diameter was 3.4 ± 0.9 cm and median R.E.N.A.L. nephrometry score was 8 (range 6-10). The mean warm ischemic time was 23.0 ± 9.2 minutes and median blood loss during surgery was 110 mL (range 70-350 mL); we had no case of uncontrollable massive bleeding. Radical nephrectomy was used in one case because of tumor embolus in a branch of the renal vein. All patients recovered well following surgery. Pathology confirmed the diagnosis of RCC in all cases, with the main subtype clear-cell carcinomas (88.2%).

CONCLUSIONS

The ring suture technique is safe and effective for management of renal hilar cancer during RLPN for selected patients.

Prognostic Outcomes and Risk Factors for Patients with Renal Cell Carcinoma and Venous Tumor Thrombus after Radical Nephrectomy and Thrombectomy: The Prognostic Significance of Venous Tumor Thrombus Level

Introduction. To evaluate the prognostic outcomes and risk factors for renal cell carcinoma (RCC) patients with venous tumor thrombus in China. Materials and Methods. We reviewed the clinical information of 169 patients who underwent radical nephrectomy and thrombectomy. Overall and cancer-specific survival rates were analyzed. Univariate and multivariate analyses were used to investigate the potential prognostic factors. Results. The median survival time was 63 months. The five-year overall survival and cancer-specific survival rate were 53.6% and 54.4% for all patients. For all patients, significant survival difference was only observed between early (below hepatic vein) and advanced (above hepatic vein) tumor thrombus. However, significant differences existed between both RV/IVC and early/advanced tumor thrombus groups in N0M0 patients. Multivariate analysis demonstrated that higher tumor thrombus level (p = 0.016, RR = 1.58), N (p = 0.013, RR = 2.60), and M (p < 0.001, RR = 4.14) stages and adrenal gland invasion (p = 0.001, RR = 4.91) were the most significant negative prognostic predictors. Conclusions. In this study, we reported most cases of RCC patients with venous extension in China. We proved that patients with RCC and venous tumor thrombus may have relative promising long-term survival rate, especially those with early tumor thrombus.

Accuracy of preoperative CT T staging of renal cell carcinoma: which features predict advanced stage?

AIMS

To characterise CT findings in renal cell carcinoma (RCC), and establish which features are associated with higher clinical T stage disease, and to evaluate patterns of discrepancy between radiological and pathological staging of RCC.

MATERIALS AND METHODS

Preoperative CT studies of 92 patients with 94 pathologically proven RCCs were retrospectively reviewed. CT stage was compared with pathological stage using the American Joint Committee on Cancer (AJCC), 7(th) edition (2010). The presence or absence of tumour necrosis, perinephric fat standing, thickening of Gerota's fascia, collateral vessels were noted, and correlated with pT stage. The sensitivity, specificity, and positive (PPV) and negative predictive values (NPV) for predicting pT stage ≥pT3a were derived separately for different predictors using cross-tabulations.

RESULTS

Twenty-four lesions were pathological stage T1a, 21 were T1b, seven were T2a, 25 were T3a, 11 were T3b, four were T3c, and two were T4. There were no stage T2b. Sixty-three (67%) patients had necrosis, 27 (29%) thickening of Gerota's fascia (1 T1a), 25 had collateral vessels (0 T1a), 28 (30%) had fat stranding of <2 mm, 20 (21%) of 2-5mm and one (1%) of >5 mm. For pT stage ≥pT3a, the presence of perinephric fat stranding had a sensitivity, specificity, PPV and NPV of 74%, 65%, 63%, and 76%, respectively. Presence of tumour necrosis had a sensitivity, specificity, PPV, and NPV of 81%, 44%, 54%, and 72%, respectively. Thickening of Gerota's fascia had a sensitivity, specificity, PPV, and NPV of 52%, 90%, 81% and 70%, respectively; and enlarged collateral vessels had a sensitivity, specificity, PPV, and NPV value of 52%, 94%, 88%, and 71% respectively.

CONCLUSION

The presence of perinephric stranding and tumour necrosis were not reliable signs for pT stage >T3a. Thickening of Gerota's fascia and the presence of collateral vessels in the peri- or paranephric fat had 90% and 94% specificity, with 82% and 88% PPV, respectively, for the presence of tumour stage for pT stage >T3a. These are considered reliable signs of locally advanced renal cancer.

Use of RENAL nephrometry scores for predicting tumor upgrading between core biopsies and surgical specimens: a prospective ex vivo study

Determination of Fuhrman grade (FG) on biopsies of renal masses is relatively inaccurate, being prone to underestimating the true grade as ascertained from surgical specimens. This study evaluated whether anatomical features of tumors could predict tumor upgrading between core biopsies and surgical specimens. We prospectively enrolled 249 patients undergoing surgical resection of solid renal masses at our institution from 2012 to 2013. Tumor anatomical features were defined using RENAL nephrometry scores. Two peripheral and 1 central ex vivo core biopsies were taken from surgical specimens with an F18-gauge needle. Logistic regression was used to assess associations between covariates and FG upgrading. A comprehensive nomogram was constructed to quantitate the probability of tumor upgrading. The median tumor size was 4.75 cm and FG upgrading occurred in 43.6% of cases. In tumors of low, intermediate, and high complexity, the risk of FG upgrading was 22.0%, 47.6%, and 50.6%, respectively. According to multivariate analyses, anatomical features R (radius) and L (location) scores correlated significantly with FG upgrading. A combination of anatomical features and core biopsy findings predicted tumor upgrading with an accuracy of 0.884. With a threshold of 30%, our nomogram identified 92.4% of cases with upgrading; however, it overrated 26.8% of patients without upgrading. This ex vivo prospective study demonstrated that RENAL nephrometry score can aid prediction of FG upgrading between core biopsies and surgical specimens. Our nomogram uses anatomical features to predict true FG from renal biopsies.

Comparison of utility of tumor size and apparent diffusion coefficient for differentiation of low- and high-grade clear-cell renal cell carcinoma

BACKGROUND

There is a significant correlation between tumor size and tumor grade for clear-cell renal cell carcinoma (RCC) in pathology. Thus, apparent diffusion coefficient (ADC) of clear-cell RCC might be influenced by tumor size.

PURPOSE

To compare the utility of tumor size and ADC for distinguishing low-grade from high-grade clear-cell RCC.

MATERIAL AND METHODS

Forty-nine patients undergoing preoperative magnetic resonance imaging were retrospectively assessed. ADC values were calculated using b-value combinations of 0 and 800 s/mm(2) at 1.5 T. Two radiologists in consensus measured ADC values via small region of interest (ROI) (mean ROI area, 88.8 mm(2); range, 80-108 mm(2)) placement on an area of solid tumor on a single slice. Maximum tumor diameter was measured at the maximum tumor area. A single pathologist reviewed all pathological slides to determine the nuclear grade according to the Fuhrman classification. The utility of ADC, tumor size, and ADC/size ratio for distinguishing low-grade from high-grade tumors was assessed. Receiver-operating characteristic (ROC) analysis and regression analysis of the each index were performed. The correlation between ADC and tumor size was also investigated.

RESULTS

The 49 clear-cell RCC included 34 low-grade and 15 high-grade tumors. The differences of ADC, tumor size, and ADC/size ratio between high-grade and low-grade tumors were statistically significant (P <0.05). The area under the ROC curve of ADC, tumor size, and ADC/size ratio were 0.802, 0.763, and 0.804 respectively. However, using regression analysis, only ADC (P <0.05) was statistically significant index as independent risk factors for high-grade clear-cell RCC. Moreover, weak significant correlation was observed between tumor size and ADC (R(2) = 0.3865, P <0.01).

CONCLUSION

There was a weak significant correlation between tumor size and ADC value of clear-cell RCC. Using ROC and regression analysis, ADC was statistically significant index for distinguishing low-grade from high-grade clear-cell RCC more than tumor size and ADC/size ratio.

Clinicopathologic patterns of adult renal tumors in Pakistan

BACKGROUND

Renal cancer is a serious public health problem which may be under reported and registered in our setup, since the Karachi cancer registry documented only 43 cases out of 4,268 incident cancer cases over 3 year duration. Therefore we aimed to determine the clinicopathologic characteristics of adult renal tumors in our setup.

MATERIALS AND METHODS

The study was conducted in histopathology department, Liaquat National Hospital and included total of 68 cases of adult renal tumors over 4 years. Detailed histopathologic characteristics of tumors were analyzed.

RESULTS

Mean age of patients was 56.4 (18-84) years. Renal cell carcinoma (RCC) was the most common cell type (78%) cases; followed by transitional/urothelial carcinoma (12.5%), leiomyosarcoma (4.7%), oncocytoma (1.6%), squamous cell carcinoma (1.6%) and high grade pleomorphic undifferentiated sarcoma (1.6%). Among 50 RCC cases; 62% were conventional/clear cell RCC (CCRCC) type followed by papillary RCC(PRCC), 24%; chromophobe RCC(CRCC), 6% and sarcomatoid RCC(SRCC), 8%. Mean tumor size for RCC was 7.2 cm. Most RCCs were intermediate to high grade (60% and 40% respectively). Capsular invasion, renal sinus invasion, adrenal gland involvement and renal vein invasion was seen in 40%, 18%, 2% and 10% of cases respectively.

CONCLUSIONS

We found that RCC presents at an earlier age in our setup compared to Western populations. Tumor size was significantly larger and most of the tumors were of intermediate to high grade. This reflects late presentation of patients after disease progression which necessitates effective measures to be taken in primary care setup to diagnose this disease at an early stage.

CT texture analysis of renal masses: pilot study using random forest classification for prediction of pathology

RATIONALE AND OBJECTIVES

Computed tomography texture analysis (CTTA) allows quantification of heterogeneity within a region of interest. This study investigates the possibility of distinguishing between several common renal masses using CTTA-derived parameters by developing and validating a predictive model.

MATERIALS AND METHODS

CTTA software was used to analyze 20 clear cell renal cell carcinomas (RCCs), 20 papillary RCCs, 20 oncocytomas, and 20 renal cysts. Regions of interest were drawn around each mass on multiple slices in the arterial, venous, and delayed phases on renal mass protocol CT scans. Unfiltered images and spatial band-pass filtered images were analyzed to quantify heterogeneity. Random forest method was used to construct a predictive model to classify lesions using quantitative parameters. The model was externally validated on a separate set of 19 unknown cases.

RESULTS

The random forest model correctly categorized oncocytomas in 89% of cases (sensitivity = 89%, specificity = 99%), clear cell RCCs in 91% of cases (sensitivity = 91%, specificity = 97%), cysts in 100% of cases (sensitivity = 100%, specificity = 100%), and papillary RCCs in 100% of cases (sensitivity = 100%, specificity = 98%).

CONCLUSIONS

CTTA, in conjunction with random forest modeling, demonstrates promise as a tool to characterize lesions. Various renal masses were accurately classified using quantitative information derived from routine scans.

Tumor grade of clear cell renal cell carcinoma assessed by contrast-enhanced computed tomography

The purpose of this study was to clarify the association between CT findings and Fuhrman grade of clear cell renal cell carcinoma (ccRCC). The study group consisted of 214 surgically proven ccRCC in 214 patients. Contrast-enhanced CT studies were retrospectively assessed for tumor size, cystic versus solid, calcification, heterogeneity of lesions, percentage of non-enhancing (necrotic) areas, and growth pattern. CT findings and Fuhrman grade were compared. Nineteen of 22 (86.4%) cystic ccRCC were low grade (Fuhrman grades 1-2). There was no significant correlation between tumor size and grade in cystic ccRCC (P = 0.43). In predominantly solid ccRCC, there was significant correlation between tumor size and grade (P < 0.0001). Thirty-eight of 43 (88.4%) infiltrative ccRCC were high grade (Fuhrman grades 3-4). Logistic regression showed tumor size and infiltrative growth were significantly associated with grades 3-4 (P = 0.00083 and P = 0.0059). Cystic ccRCC tends to be low grade. Infiltrative growth and larger tumor size may increase the likelihood of high grade ccRCC.

Multiparametric magnetic resonance imaging for the differentiation of low and high grade clear cell renal carcinoma

PURPOSE

To retrospectively evaluate the ability of magnetic resonance (MR) imaging to differentiate low from high Fuhrman grade renal cell carcinoma (RCC).

MATERIALS AND METHODS

MR images from 80 consecutive pathologically proven RCC (57 clear cell, 16 papillary and 7 chromophobe) were evaluated. Double-echo chemical shift, dynamic contrast-enhanced T1- and T2-weighted images and apparent diffusion coefficient (ADC) maps were reviewed independently. Signal intensity index (SII), tumour-to-spleen SI ratio (TSR), ADC ratio, wash-in (WiI) and wash-out indices (WoI) between different phases were calculated and compared to pathological grade and size. The Fuhrman scoring system was used. Low grade (score ≤ 2) and high grade (score ≥ 3) tumours were compared using univariate and multivariate analyses.

RESULTS

No associations between grade and imaging factors were found for papillary and chromophobe RCCs. For clear cell RCCs, there was a significant association between the grade and parenchymal WiI (WiI2) (P = 0.02) or ADCr (P = 0.03). A significant association between tumour grade and size (P = 0.01), WiI2 (P = 0.02) and ADCr (P = 0.05) remained in multivariate analysis.

CONCLUSIONS

Multiparametric MRI can be used to accurately differentiate low Fuhrman grade clear cell RCC from high grade. High Fuhrman grade (≥ 3) RCCs were larger, had lower parenchymal wash-in indices and lower ADC ratios than low grade.

KEY POINTS

• Fuhrman grade of clear cell RCC can be differentiated with multiparametric MR imaging. • Fuhrman grade significantly differed for size, parenchymal wash-in index and ADC ratio. • No significant associations were found for papillary and chromophobe renal cell carcinoma.

Chromophobe renal cell carcinoma: multiphase MDCT enhancement patterns and morphologic features

OBJECTIVE

The purpose of this investigation is to retrospectively describe morphologic features, enhancement characteristics, and clinical outcomes in a series of pathologically proven chromophobe renal cell carcinomas (RCCs).

MATERIALS AND METHODS

Thirty-five patients who were imaged at a single institution between 2005 and 2012 with pathologically proven chromophobe RCC were identified, all of whom underwent preoperative renal protocol CT (unenhanced, arterial, venous, and delayed images). The morphologic characteristics of each tumor (e.g., necrosis, tumor composition, and calcification), as well as attenuation values (in Hounsfield units) of the tumor, aorta, inferior vena cava, and kidney were evaluated by a board-certified radiologist. In addition, information regarding patient demographics and survival was obtained by a separate radiologist from the electronic medical record.

RESULTS

Sixty percent of the patients were men, with a mean age of 60.2 years. Forty-six percent of cases were incidentally identified, without patient symptoms. None of the patients had evidence of distant metastatic disease, either on initial staging CT or over the course of follow-up (mean, 2.0 years). Mean maximal tumor diameter was 5.24 cm. Forty-six percent of tumors were homogeneous, 85% of lesions were either completely solid or mostly solid, 14% showed calcifications, and 34% showed a central scar or necrosis. Mean maximum attenuation values were 87.9 HU (arterial phase), 83.9 HU (venous phase), and 60.6 HU (delayed phase), with an average delayed washout of 31%. Tumor-to-cortex ratios for the three enhanced phases were 0.59, 0.48, and 0.50, respectively.

CONCLUSION

Chromophobe RCCs were found to have a wider variability of CT features than previously reported, although they do have a greater propensity for homogeneity and the presence of a central scar or necrosis. Their enhancement characteristics fall in between those of clear cell and papillary RCC, although there is considerable overlap.

Kidney volume correlates with tumor diameter in renal cell carcinoma and is associated with histological poor prognostic features

We aimed to correlate kidney volume (KV) in renal cell carcinoma nephrectomy specimens with tumor diameter (TD), macroscopic growth pattern, and histological features associated with poor prognosis. Histopathology reports, macroscopic specimen photographs, and selected glass slides were retrospectively reviewed. KV was approximated to the volume of an ellipsoid. A total of 273 specimens were identified with median KV 245 cm(3). Kidneys larger than this contained larger tumors (7.5 vs 4.5 cm). KV was significantly greater in tumors of high grade, involving perinephric fat, exhibiting venous invasion, and involving renal sinus. There was a robust linear correlation between KV and TD (r = 0.602) and a weaker correlation between kidney diameter (KD) and TD (r = 0.53). In pT1 tumors, KV (r = 0.40) also correlated better with TD than did KD (r = 0.27). By multiple regression analysis, both TD and venous invasion independently predicted both KD (R (2) = 38.27%) and KV (R (2) = 51.97%). KV and KD correlate well with TD and histopathological features of aggressiveness, although KD correlates better overall and in the pT1 subset.

Evaluation of renal masses with contrast-enhanced ultrasound

The clinical need for characterising small renal masses (SRMs) is increasing due to their rising incidental detection. This increase is especially seen in younger and older generations and concerns mainly SRMs. Diagnostics is mainly made by contrast-enhanced CT or MRI. However, these imaging methods fail to accurately distinguishing benign from malignant SRMs. Other disadvantages of CT or MRI are high costs, the use of ionizing radiation, nephrotoxicity induced by iodine contrast agents or nephrogenic systemic fibrosis (NSF) induced by gadolinium contrast agents. Contrast-enhanced ultrasound (CEUS) is based on ultrasonography and microbubbles to real-time visualize the renal blood flow without the use of nephrotoxic agents or ionizing radiation. This comprehensive review evaluates the capabilities of CEUS in the diagnostics of benign (angiomyolipomas, cysts, oncocytomas, pseudotumors) and malignant masses (renal cell carcinomas), and focuses on possible future treatment.

Assessment of intratumoral micromorphology for patients with clear cell renal cell carcinoma using susceptibility-weighted imaging

Background

Multiple treatment options exist for the management of renal cell carcinomas. Preoperative evaluation of clear cell renal cell carcinoma (CRCC) grades is important for deciding upon the appropriate method of therapy. We hypothesize that susceptibility weighted imaging (SWI) is sensitive enough to detect intratumoral microvessles and microbleeding in renal cell carcinoma, which can be used to grade CRCC.

Material and Methods

Retrospective reviews of 37 patients with pathologically proven CRCCs were evaluated. All patients underwent SWI examinations. The characteristics of intratumoral susceptibility signal intensity (ITSS) includes the likelihood of the presence of ITSS, morphology of ITSS, dominant structure of ITSS and ratio of ITSS area to tumor area, which were all assessed on SWI. The results were compared using the nonparametric Mann-Whitney test.

Results

ITSS was seen in all patients except 4 patients with low-grade CRCCs. There was no significant difference between low and high-grade CRCCs when looking at the likelihood of the presence of ITSS. There was a significant difference in the mean score of dominant structures between low and high-grade CRCCs. Specifically, more dominant vascular structures and less hemorrhage were seen in low-grade tumors (2.15±1.05) compared to high-grade tumors (1.27±0.47) (P<0.005). The ratio of ITSS area to tumor area was also significantly higher for the high-grade group (1.55±0.52) than that for the low-grade group (0.88±0.43) on SWI (P<0.005).

Conclusion

SWI is useful for grading CRCCs.