Update on radiological imaging of renal cell carcinoma

Multiphase comparative study for WHO/ISUP nuclear grading diagnostic model based on enhanced CT images of clear cell renal cell carcinoma

To compare and analyze the diagnostic value of different enhancement stages in distinguishing low and high nuclear grade clear cell renal cell carcinoma (ccRCC) based on enhanced computed tomography (CT) images by building machine learning classifiers. A total of 51 patients (Dateset1, including 41 low-grade and 10 high-grade) and 27 patients (Independent Dateset2, including 16 low-grade and 11 high-grade) with pathologically proven ccRCC were enrolled in this retrospective study. Radiomic features were extracted from the corticomedullary phase (CMP), nephrographic phase (NP), and excretory phase (EP) CT images, and selected using the recursive feature elimination cross-validation (RFECV) algorithm, the group differences were assessed using T-test and Mann-Whitney U test for continuous variables. The support vector machine (SVM), random forest (RF), XGBoost (XGB), VGG11, ResNet18, and GoogLeNet classifiers are established to distinguish low-grade and high-grade ccRCC. The classifiers based on CT images of NP (Dateset1, RF: AUC = 0.82 ± 0.05, ResNet18: AUC = 0.81 ± 0.02; Dateset2, XGB: AUC = 0.95 ± 0.02, ResNet18: AUC = 0.87 ± 0.07) obtained the best performance and robustness in distinguishing low-grade and high-grade ccRCC, while the EP-based classifier performance in poorer results. The CT images of enhanced phase NP had the best performance in diagnosing low and high nuclear grade ccRCC. Firstorder_Kurtosis and firstorder_90Percentile feature play a vital role in the classification task.

Using machine learning to predict lymph node metastasis in patients with renal cell carcinoma: A population-based study

Background

Lymph node (LN) metastasis is strongly associated with distant metastasis of renal cell carcinoma (RCC) and indicates an adverse prognosis. Accurate LN-status prediction is essential for individualized treatment of patients with RCC and to help physicians make appropriate surgical decisions. Thus, a prediction model to assess the hazard index of LN metastasis in patients with RCC is needed.

Methods

Partial data were extracted from the Surveillance, Epidemiology, and End Results (SEER) database. Data of 492 individuals with RCC, collected from the Southwest Hospital in Chongqing, China, were used for external validation. Eight indicators of risk of LN metastasis were screened out. Six machine learning (ML) classifiers were established and tuned, focused on predicting LN metastasis in patients with RCC. The models were integrated with big data analytics and ML algorithms. Based on the optimal model, we developed an online risk calculator and plotted overall survival using Kaplan-Meier analysis.

Results

The extreme gradient-boosting (XGB) model was superior to the other models in both internal and external trials. The area under the curve, accuracy, sensitivity, and specificity were 0.930, 0.857, 0.856, and 0.873, respectively, in the internal test and 0.958, 0.935, 0.769, and 0.944, respectively, in the external test. These parameters show that XGB has an excellent ability for clinical application. The survival analysis showed that patients with predicted N1 tumors had significantly shorter survival (p < 0.0001).

Conclusion

Our study shows that integrating ML algorithms and clinical data can effectively predict LN metastasis in patients with confirmed RCC. Subsequently, a freely available online calculator (https://xinglinyi.shinyapps.io/20221004-app/) was built, based on the XGB model.

A Novel Nomogram for Prediction and Evaluation of Lymphatic Metastasis in Patients With Renal Cell Carcinoma

Background

Lymphatic metastasis is an important mechanism of renal cell carcinoma (RCC) dissemination and is an indicator of poor prognosis. Therefore, we aimed to identify predictors of lymphatic metastases (LMs) in RCC patients and to develop a new nomogram to assess the risk of LMs.

Methods

This study included patients with RCC from 2010 to 2018 in the Surveillance, Epidemiology, and Final Results (SEER) database into the training cohort and included the RCC patients diagnosed during the same period in the Second Affiliated Hospital of Dalian Medical University into the validation cohort. Univariate and multivariate logistic regression analysis were performed to identify risk factors for LM, constructing a nomogram. The receiver operating characteristic (ROC) curves were generated to assess the nomogram’s performance, and the concordance index (C-index), area under curve value (AUC), and calibration plots were used to evaluate the discrimination and calibration of the nomogram. The nomogram’s clinical performance was evaluated by decision curve analysis (DCA), probability density function (PDF) and clinical utility curve (CUC). Furthermore, Kaplan-Meier curves were performed in the training and the validation cohort to evaluate the survival risk of the patients with lymphatic metastasis or not. Additionally, on the basis of the constructed nomogram, we obtained a convenient and intuitive network calculator.

Results

A total of 41837 patients were included for analysis, including 41,018 in the training group and 819 in the validation group. Eleven risk factors were considered as predictor variables in the nomogram. The nomogram displayed excellent discrimination power, with AUC both reached 0.916 in the training group (95% confidence interval (CI) 0.913 to 0.918) and the validation group (95% CI 0.895 to 0.934). The calibration curves presented that the nomogram-based prediction had good consistency with practical application. Moreover, Kaplan-Meier curves analysis showed that RCC patients with LMs had worse survival outcomes compared with patients without LMs.

Conclusions

The nomogram and web calculator (https://liwenle0910.shinyapps.io/DynNomapp/) may be a useful tool to quantify the risk of LMs in patients with RCC, which may provide guidance for clinicians, such as identifying high-risk patients, performing surgery, and establishing personalized treatment as soon as possible.

Renal Cell Carcinoma Associated With HIV/AIDS: A Review of the Epidemiology, Risk Factors, Diagnosis, and Treatment

Renal cell carcinoma (RCC), one of the most common genitourinary tumors, is induced by many factors, primarily smoking, obesity, and hypertension. As a non-acquired immunodeficiency syndrome (AIDS)-defining cancer, human immunodeficiency virus (HIV) may also play a critical role in the incidence and progression of RCC. It is evident that individuals who are infected with HIV are more likely than the general population to develop RCC. The age of RCC diagnosis among HIV-positive patients is younger than among HIV-negative individuals. However, many other characteristics remain unknown. With the increase in RCC incidence among HIV-infected patients, more research is being conducted to discover the relationship between RCC and HIV, especially with regard to HIV-induced immunodeficiency, diagnosis, and treatment. Unexpectedly, the majority of the literature suggests that there is no relationship between RCC and HIV-induced immunodeficiency. Nonetheless, differences in pathology, symptoms, or treatment in HIV-positive patients diagnosed with RCC are a focus. In this review, we summarize the association of RCC with HIV in terms of epidemiology, risk factors, diagnosis, and treatment.

Cross-sectional imaging assessment of renal masses with emphasis on MRI

Magnetic resonance imaging (MRI) is a useful complementary imaging tool for the diagnosis and characterization of renal masses, as it provides both morphologic and functional information. A core MRI protocol for renal imaging should include a T1-weighted sequence with in- and opposed-phase images (or, alternatively with DIXON technique), T2-weighted and diffusion-weighted images as well as a dynamic contrast-enhanced sequence with subtraction images, followed by a delayed post-contrast T1-weighted sequence. The main advantages of MRI over computed tomography include increased sensitivity for contrast enhancement, less sensitivity for detection of calcifications, absence of pseudoenhancement, and lack of radiation exposure. MRI may be applied for renal cystic lesion characterization, differentiation of renal cell carcinoma (RCC) from benign solid renal tumors, RCC histologic grading, staging, post-treatment follow-up, and active surveillance of patients with treated or untreated RCC.

Laparoscopic Radical Nephrectomy

In addition to its established advantages, laparoscopic radical nephrectomy (RN) poses a unique set of challenges over traditional open surgery. In this study, we discuss preoperative considerations and detailed steps for laparoscopic RN. We review the transabdominal approach in detail, including patient positioning, equipment, and port placement in addition to the surgical steps. Intraoperative decisions such as adrenal management, renal preservation, and tumor identification are reviewed. Common complications of laparoscopic renal surgery are also summarized.

How accurate is radiological imaging for perirenal fat and renal vein invasion in renal cell carcinoma?

OBJECTIVE

To evaluate the accuracy of radiological staging, especially renal venous and perirenal fat invasion, in renal cell carcinoma (RCC).

MATERIAL AND METHODS

Data of 4823 renal tumour patients from Renal Tumor Database of Association of Uro-oncology in Turkey were evaluated. Of 4823 patients, 3309 RCC patients had complete radiological, and histopathological data were included to this study. The Pearson chi-squared test (χ² ) was used to compare radiological and histopathological stages.

RESULTS

The mean (SD) age of 3309 patients was 58 (12.3). Preoperative radiological imaging was performed using computed tomography (CT) (n = 2510, 75.8%) or magnetic resonance imaging (MRI) (n = 799, 24.2%). There was a substantial concordance between radiological and pathological staging (к = 0.52, P < .001). Sensitivities of radiological staging in stages I, II, III and IV were 90.7%, 67.3%, 27.7% and 64.2%, respectively. The sensitivity in stage III was lower than the other stages. Subanalysis of stage IIIa cases revealed that, for perirenal fat invasion and renal vein invasion, sensitivity values were 15.4% and 11.3%, respectively.

CONCLUSIONS

There was a substantial concordance between radiological (CT and/or MRI) and pathological T staging in RCC. However, this is not true for T3 cases. Sensitivity of preoperative radiological imaging in patients with pT3a tumours is insufficient and lower than the other stages. Consequently, preoperative imaging in patients with T3 RCC has to be improved, in order to better inform the patients regarding prognosis of their disease.

Is lymph node dissection necessary for staging while undergoing nephrectomy in patients with renal cell carcinoma?

OBJECTIVE

The essential treatment for patients with renal cell carcinoma is nephrectomy. As no lymph node dissection (LND) could be performed in the majority of these patients, healthy staging could not be carried out. In this study, we investigated the impact of LND during nephrectomy on patient survival.

METHODS

A total of 181 patients-58 (32%) were female and 123 (68%) were male-were included in the study. Median follow-up period was 48 months. The patients were separated into 4 groups according to their stage during diagnosis; group 1 (T1-3N0M0), group 2 (T1-3NXM0), group 3 (T1-3N1M0), and group 4 (T1-4N0/XM1). The disease-free survival of nonmetastatic patients and the overall survival of all groups were calculated.

RESULTS

Mean age was 58.4 ± 12.0 years. Median survival for Group 1 could not be reached. Median survival was 89 months in Group 2, 50 months in Group 3, and 39 months in Group 4 (P <0.001). There was no statistically significant difference between the N1 and M1 groups (P = 0.297). For the NX patient group without LND, median survival was 89 months, which is worse than the N0 group and better than the N1 group (P = 0.002).

CONCLUSIONS

Our study presumes that the patients without LND are not staged sufficiently, NX patients have worse survival rates when compared with N0 patients, node-positive patients have poor survival rates as do the metastatic patients, and it should be defined as TNM stage4.

Role of MRI in staging and surgical planning and its clinicopathological correlation in patients with renal cell carcinoma

Background and Aims:

Radiological evaluation of renal cell carcinoma (RCC) is used for non-invasive staging for better surgical planning. However, the correlation of radiological staging using magnetic resonance imaging (MRI) with histopathological findings has not been done so far. The aim of this study is to assess the role of MRI in pre-operative staging of RCC in patients undergoing radical nephrectomy and nephron sparing surgery (NSS) and correlate it with histopathological findings.

Settings and Design:

This prospective observational study was conducted from February 2015 to October 2016 at a tertiary care hospital in northern India.

Methods:

MR imaging was done on 3 Tesla MR scanner (Signa Hdxt General Electrics, Milwaukee, USA). Preoperative staging was based on 2010 TNM staging system. The preoperative parameters in MRI were tumor size, detection/breach of pseudocapsule, tumor extension into perirenal fat and detection of tumor venous thrombus. The staging on MRI was compared with surgical and pathological staging.

Statistical Analysis Used:

The agreement between these three staging methods was determined using the kappa statistics (0.0-0.2, poor; 0.2-0.4, fair; 0.4-0.6, moderate; 0.6-0.8, good; 0.8-1.0, excellent).

Results:

30 patients with suspected RCC underwent NSS (n = 10) and radical nephrectomy (n = 20). Mean tumor size was 9.66 ± 2.99 cm in the radical nephrectomy group and 4.06 ± 1.16 cm in the NSS group. There was perfect agreement between MRI, surgical and pathological staging for breach of pseudocapsule (κ =1.0, Percentage of Agreement = 100%, P < 0.05). In none of the patients, MRI missed extension beyond the Gerota's fascia or presence of venous thrombus.

Conclusion:

MRI staging of RCC is an accurate predictor of the surgical and pathological stage and has the potential to become a useful tool for preoperative identification of patients with RCC who can undergo NSS.

Predictive and prognostic effect of inflammatory lymphadenopathies in renal cell carcinoma

PURPOSE

A significant proportion of patients affected by renal cell carcinoma (RCC) shows a suspicious lymph node involvement (LNI) at preoperative imaging. We sought to evaluate the effect of lymphadenopathies (cN1) on survival in surgical RCC patients with no evidence of LNI at final pathology (pN0).

METHODS

719 patients underwent either radical or partial nephrectomy and lymph node dissection at a single tertiary care referral centre between 1987 and 2015. All patients had pathologically no LNI (pN0). Outcomes of the study were cancer-specific mortality (CSM) and other-cause mortality. Multivariable competing-risks regression models assessed the impact of inflammatory lymphadenopathies (cN1pN0) on mortality rates, after adjustment for clinical and pathological confounders.

RESULTS

114 (16%) and 605 (84%) patients (16%) were cN1pN0 and cN0pN0, respectively. cN1pN0 patients were more frequently diagnosed with larger tumours (8.4 vs. 6.5 cm), higher pathological tumour stage (pT3-4 in 71 vs. 36%), higher Fuhrman grade (G3-G4 in 64 vs. 31%), more frequently with necrosis (75 vs. 44%), and distant metastases (33 vs. 10%) (all p < 0.0001). At univariable analysis, inflammatory lymphadenopathies resulted associated with worse CSM (HR 2.45; p < 0.0001). However, at multivariable analysis, inflammatory lymphadenopathies were not an independent predictor of CSM (HR 0.81; p = 0.4). The presence of metastases at diagnosis was the most important factor affecting CSM (HR 6.54; p < 0.0001). This study is limited by its retrospective nature.

CONCLUSIONS

In RCC patients, inflammatory lymphadenopathies (cN1pN0) are associated with unfavourable clinical and pathological characteristics. However, the presence of inflammatory lymphadenopathies does not affect RCC-specific mortality.

Visual evaluation and differentiation of renal oncocytomas from renal cell carcinomas by means of 99mTc-sestamibi SPECT/CT

Background

Despite the progress in the quality of multiphasic CT and MRI scans, it is still difficult to fully characterize a solid kidney lesion. Approximately 10% of all solid renal tumours turn out to be oncocytomas. In actual clinical practice, this is verified only following unnecessary surgery or a renal biopsy/ablation. The objective of our pilot study examines whether ^99mTc-sestamibi SPECT/CT can play a crucial role in the characterization of solid renal neoplasms and the differentiation of oncocytomas from renal cell carcinomas.

The study included 27 patients identified with 31 solid renal lesions. All patients were discussed in a multidisciplinary conference, and a decision for surgery or biopsy was taken. Prior to invasive procedures, patients underwent a SPECT/CT with ^99mTc-sestamibi. Visual evaluation was performed, and any focal ^99mTc-sestamibi uptake detected on SPECT in the localisation of tumour was considered as positive.

Results

Eleven out of 12 oncocytomas (91.6%) displayed positive uptake of ^99mTc-sestamibi. Three hybrid tumours (mixed-type oncocytoma and chromophobe renal cancer) were positive on SPECT/CT. One papillary renal cell carcinoma had a slight uptake of ^99mTc-sestamibi. The remaining 11 renal cell carcinomas were sestamibi negative.

Conclusions

Differentiation of benign renal oncocytomas from renal cell carcinomas seems very promising on ^99mTc-sestamibi SPECT/CT examination. Additional supplement to visual evaluation, i.e. quantitative tools, should be sought for an accurate estimate of biological behaviour and hence a secure diagnosis.

Diagnostic accuracy of contrast-enhanced computed tomography and contrast-enhanced magnetic resonance imaging of small renal masses in real practice: sensitivity and specificity according to subjective radiologic interpretation

Background

The aim of this study was to investigate the diagnostic accuracy of contrast-enhanced computed tomography (CT) and contrast-enhanced magnetic resonance imaging (MRI) of small renal masses in real practice.

Methods

Contrast-enhanced CT and MRI were performed between February 2008 and February 2013 on 68 patients who had suspected small (≤4 cm) renal cell carcinoma (RCC) based on ultrasonographic measurements. CT and MRI radiographs were reviewed, and the findings of small renal masses were re-categorized into five dichotomized scales by the same two radiologists who had interpreted the original images. Receiver operating characteristics curve analysis was performed, and sensitivity and specificity were determined.

Results

Among the 68 patients, 60 (88.2 %) had RCC and eight had benign disease. The diagnostic accuracy rates of contrast-enhanced CT and MRI were 79.41 and 88.23 %, respectively. Diagnostic accuracy was greater when using contrast-enhanced MRI because too many masses (67.6 %) were characterized as “4 (probably solid cancer) or 5 (definitely solid cancer).” The sensitivity of contrast-enhanced CT and MRI for predicting RCC were 79.7 and 88.1 %, respectively. The specificities of contrast-enhanced CT and MRI for predicting RCC were 44.4 and 33.3 %, respectively. Fourteen diagnoses (20.5 %) were missed or inconsistent compared with the final pathological diagnoses. One appropriate nephroureterectomy and five unnecessary percutaneous biopsies were performed for RCC. Seven unnecessary partial nephrectomies were performed for benign disease.

Conclusions

Although contrast-enhanced CT and MRI showed high sensitivity for detecting small renal masses, specificity remained low.

Advances of multidetector computed tomography in the characterization and staging of renal cell carcinoma

Renal cell carcinoma (RCC) accounts for approximately 90%-95% of kidney tumors. With the widespread use of cross-sectional imaging modalities, more than half of RCCs are detected incidentally, often diagnosed at an early stage. This may allow the planning of more conservative treatment strategies. Computed tomography (CT) is considered the examination of choice for the detection and staging of RCC. Multidetector CT (MDCT) with the improvement of spatial resolution and the ability to obtain multiphase imaging, multiplanar and three-dimensional reconstructions in any desired plane brought about further improvement in the evaluation of RCC. Differentiation of RCC from benign renal tumors based on MDCT features is improved. Tumor enhancement characteristics on MDCT have been found closely to correlate with the histologic subtype of RCC, the nuclear grade and the cytogenetic characteristics of clear cell RCC. Important information, including tumor size, localization, and organ involvement, presence and extent of venous thrombus, possible invasion of adjacent organs or lymph nodes, and presence of distant metastases are provided by MDCT examination. The preoperative evaluation of patients with RCC was improved by depicting the presence or absence of renal pseudocapsule and by assessing the possible neoplastic infiltration of the perirenal fat tissue and/or renal sinus fat compartment.

A Literature Review of Renal Surgical Anatomy and Surgical Strategies for Partial Nephrectomy

CONTEXT

A detailed understanding of renal surgical anatomy is necessary to optimize preoperative planning and operative technique and provide a basis for improved outcomes.

OBJECTIVE

To evaluate the literature regarding pertinent surgical anatomy of the kidney and related structures, nephrometry scoring systems, and current surgical strategies for partial nephrectomy (PN).

EVIDENCE ACQUISITION

A literature review was conducted.

EVIDENCE SYNTHESIS

Surgical renal anatomy fundamentally impacts PN surgery. The renal artery divides into anterior and posterior divisions, from which approximately five segmental terminal arteries originate. The renal veins are not terminal. Variations in the vascular and lymphatic channels are common; thus, concurrent lymphadenectomy is not routinely indicated during PN for cT1 renal masses in the setting of clinically negative lymph nodes. Renal-protocol contrast-enhanced computed tomography or magnetic resonance imaging is used for standard imaging. Anatomy-based nephrometry scoring systems allow standardized academic reporting of tumor characteristics and predict PN outcomes (complications, remnant function, possibly histology). Anatomy-based novel surgical approaches may reduce ischemic time during PN; these include early unclamping, segmental clamping, tumor-specific clamping (zero ischemia), and unclamped PN. Cancer cure after PN relies on complete resection, which can be achieved by thin margins. Post-PN renal function is impacted by kidney quality, remnant quantity, and ischemia type and duration.

CONCLUSIONS

Surgical renal anatomy underpins imaging, nephrometry scoring systems, and vascular control techniques that reduce global renal ischemia and may impact post-PN function. A contemporary ideal PN excises the tumor with a thin negative margin, delicately secures the tumor bed to maximize vascularized remnant parenchyma, and minimizes global ischemia to the renal remnant with minimal complications.

PATIENT SUMMARY

In this report we review renal surgical anatomy. Renal mass imaging allows detailed delineation of the anatomy and vasculature and permits nephrometry scoring, and thus precise, patient-specific surgical planning. Novel off-clamp techniques have been developed that may lead to improved outcomes.

Pretreatment differentiation of renal cell carcinoma subtypes by CT: the influence of different tumor enhancement measurement approaches

PURPOSE

We conducted a retrospective study to evaluate the influence of different tumor enhancement measurement approaches on the ability of computed tomography (CT) to differentiate between solid forms of clear cell renal cell carcinoma (RCC), other RCC histologic subtypes and oncocytomas. Different RCC subtypes have a diverse range of malignant potential; consequently, the information about RCC subtype obtained using minimally invasive imaging method before the treatment could allow the more accurate therapy planning. Differentiation of ccRCCs from oncocytomas is important because oncocytomas are usually benign tumors which could be treated conservatively.

METHODS

CT images of 113 patients with 118 solid renal tumors were evaluated. The imaging protocol consisted pre-contrast and post-contrast images during the arterial and nephrographic phases. Renal tumor attenuation values were measured using region of interest covering as much of the solid enhancing tumor tissue as possible. Tumor attenuation values and tumor enhancement ratios were correlated with histologic subtype. One hundred of tumors were diagnosed as clear cell RCC, nine as non-clear cell RCC and nine as oncocytoma.

RESULTS

Tumor attenuation values of >74 HU on the arterial phase scans significantly correlated with clear cell RCC (Az 0.73). The tumor-to-aorta enhancement ratios calculated on tumor attenuation values measured on the arterial phase scans had a cutoff value of >0.29, which significantly correlated with clear cell RCC (Az 0.79). All ROC curves for differentiating the clear cell RCC from oncocytomas have area under the curve too small (0.5 or less) to have chose cutoff value with sensitivity and specificity that could be applied in clinical work.

CONCLUSION

Enhancement measurements of renal carcinomas on CT images in the arterial phase can be used as an auxiliary method in the pretreatment differentiation of solid forms of the most frequent RCC subtypes in patients not suitable for core biopsy but who are suitable for minimally invasive treatment methods and/or targeted therapy.

Low-grade clear cell renal cell carcinoma mimicking hemangioma of the kidney: a series of 4 cases

CONTEXT

Clear cell renal cell carcinoma (CCRCC) has a rich, sinusoid-like vascularity frequently used as a diagnostic criterion. CCRCC with predominantly vascular architecture has not been described.

OBJECTIVE

To describe 4 unusual CCRCC cases, primarily presenting with hemangioma-like morphologic pattern.

DESIGN

Clinicopathologic and selected immunohistochemical analysis of 4 cases of CCRCC mimicking hemangioma.

RESULTS

Cases were seen in 1 woman and 3 men (average age, 48.8 years; range, 40-66 years). Grossly, tumors were red-brown (3 of 4) with scant bright-yellow foci in 1. The average tumor size was 4 cm (range, 2.5-5.5 cm). Microscopically, all were composed of varying proportions of a rich, arborizing, sinusoid-like vasculature with focal hobnail appearance of endothelial cells. Entrapment of renal tubules between blood vessels was seen at the periphery of the tumors. This morphology was reminiscent of anastomosing hemangioma. Isolated tumor cells resembling lymphocytes with clear halos were sparsely interspersed between vessels. Cytokeratin immunostain confirmed the diagnosis of CCRCC.

CONCLUSION

Extensive sampling and immunohistochemical workup of what is deemed to be a benign vascular neoplasm of the kidney is needed to rule out the presence of individual carcinoma cells or small viable carcinoma cell clusters.

CD10+ and CK7/RON- immunophenotype distinguishes renal cell carcinoma, conventional type with eosinophilic morphology from its mimickers

BACKGROUND

The distinction between renal cell carcinoma conventional (clear cell) type with eosinophilic morphology (ccRCC), chromophobe renal cell carcinoma eosinophilic variant (chRCC), and renal oncocytoma (RO) is a common diagnostic dilemma. We aimed to identify an immunohistochemical panel to discriminate ccRCC from its morphologic mimics.

MATERIALS AND METHODS

Fifty-three renal neoplasms (19 ccRCC, 18 chRCC, and 16 RO) were selected. Immunohistochemical stains for CD10, cytokeratin 7 (CK7), c-Kit, E-cadherin, N-cadherin, kidney-specific cadherin (Ksp-cadherin), and Recepteur d'origine nantais (RON) were performed.

RESULTS

Ten (53%) of 19 ccRCC were positive for CD10, 11 (58%) for E-cadherin, 8 (42%) for N-cadherin, 5 (26%) for Ksp-cadherin, 9 (47%) for RON, 6 (32%) for CK7, and 5 (26%) for c-Kit. In chRCC/RO group, 5 of 34 (15%) were positive for CD10, 32 (94%) for E-cadherin, 2 (6%) for N-cadherin, 1 (3%) for Ksp-cadherin, 22 (65%) for RON, 14 (41%) for CK7, and 25 (25/32, 76%) for c-kit. Univariately, negative c-Kit [odds ratio (OR)=8.75, P=0.001, area under the receiver operating characteristic curve (AUC)=0.747], negative E-cadherin (OR=11.64, P=0.005, AUC=0.681), positive N-cadherin (OR=11.64, P=0.005, AUC=0.681), positive Ksp-cadherin (OR=11.79, P=0.031, AUC=0.617), and positive CD10 (OR=6.44, P=0.005, AUC=0.690) detects ccRCC versus chRCC/RO. Multivariate analysis showed significant association between CD10 positivity and ccRCC (OR=16.90, P=0.007) and between RON negativity and ccRCC (OR=7.17, P=0.047) when CK7 is negative.

CONCLUSIONS

The best single predictors for ccRCC are negative c-Kit, negative E-cadherin, positive N-cadherin, positive Ksp-cadherin, and positive CD10. However, considering the studied markers, a combination of positive CD10 and negative CK7 and RON is considered the best immunohistochemical panel in distinguishing ccRCC from chRCC/RO.

Predicting the histology of small renal masses using preoperative dynamic contrast-enhanced magnetic resonance imaging

OBJECTIVE

To study whether magnetic resonance imaging can predict the histologic type of small renal cell carcinoma.

METHODS

Dynamic contrast-enhanced magnetic resonance imaging was performed in 63 patients with computed tomography- or ultrasonography-suspected small (≤ 4 cm) renal cell carcinoma from February 2008 to February 2010. Percentage signal intensity change, tumor-to-cortex enhancement index during precontrast phase, corticomedullary phase, and nephrogenic phase were investigated.

RESULTS

Among the 60 patients, 42 were proven to have clear cell renal cell carcinoma and 18 patients were proven to have non-clear cell renal cell carcinoma (10 patients with papillary renal cell carcinoma, 8 patients with chromophobe renal cell carcinoma). The percentage signal intensity change in the clear cell type was higher only in the corticomedullary phase (P = .002). The tumor-to-cortex enhancement index in the clear cell type was higher in the corticomedullary and nephrogenic phases (P = .007 and P = .041, respectively). The most valuable marker was percentage signal intensity change in the corticomedullary phase (area under the receiver operating characteristic curve 0.85). The cut-off value of percentage signal intensity change in the corticomedullary phase was 173%, and the sensitivity and specificity were 81% and 87.5%, respectively.

CONCLUSION

Dynamic contrast-enhanced magnetic resonance imaging could be useful for discriminating the clear cell type from non-clear cell type in small renal cell carcinoma with high sensitivity and specificity.

Pathological implications of areas of lower enhancement on contrast-enhanced computed tomography in renal-cell carcinoma: additional information for selecting candidates for surveillance protocols

PURPOSE

Areas of lower enhancement on computed tomography are frequently seen in renal-cell carcinoma. We investigated whether tumor enhancement on the most prominent hypodense areas correlates with the nuclear grade and other pathologic variables.

METHODS

From 2004 to 2009, all consecutive patients with a preoperative tomography who underwent radical or partial nephrectomy for renal-cell carcinoma at our tertiary referral center were retrospectively analyzed. Enhancement of the entire tumor on the slice with most prominent areas of lower enhancement was determined.

RESULTS

Forty-eight patients were included. Clear-cell carcinoma comprised 91.6 %. Mean areas of lower enhancement for nuclear grade tumors 1-4 were 67.4, 38.7, 27.9, and 15.1 HU, respectively. Areas of lower enhancement negatively correlated with size, nuclear grade, T stage, and pathological stage. Tumors with extension beyond Gerota's fascia (10.5 vs. 35.9 HU, p < 0.001) and positive surgical margins (21.2 vs. 34.8 HU, p = 0.04) had more prominent areas of lower enhancement than organ-confined tumors. When comparing nuclear grade 1-3 to nuclear grade 4 tumors, these areas were significantly lower in the later (36.5 vs. 15.1 HU, p < 0.001). Receiver-operating characteristics curves for detecting nuclear grade 4 showed an area under the curve of 0.808 (95 % CI 0.659-0.957).

CONCLUSIONS

Lower enhancement of the entire tumor at the point where hypodense tumor areas are more predominant on tomography is associated with higher nuclear grade and more advanced stage.

Lymph node dissection in renal cell carcinoma

CONTEXT

Although lymphadenectomy (lymph node dissection [LND]) is currently accepted as the most accurate and reliable staging procedure for the detection of lymph node invasion (LNI), its therapeutic benefit in renal cell carcinoma (RCC) still remains controversial.

OBJECTIVE

Review the available literature concerning the role of LND in RCC staging and outcome.

EVIDENCE ACQUISITION

A Medline search was conducted to identify original articles, review articles, and editorials addressing the role of LND in RCC. Keywords included kidney neoplasms, renal cell cancer, renal cell carcinoma, kidney cancer, lymphadenectomy, lymph node excision, lymphatic metastases, nephrectomy, imaging, and complications. The articles with the highest level of evidence were identified with the consensus of all of the collaborative authors and were critically reviewed. This review is the result of an interactive peer-reviewing process by an expert panel of co-authors.

EVIDENCE SYNTHESIS

Renal lymphatic drainage is unpredictable. The newer available imaging techniques are still immature in detecting small lymph node metastases. Results from the European Organization for Research and Treatment of Cancer trial 30881 showed no benefit in performing LND during surgery for clinically node-negative RCC, but the results are limited to patients with the lowest risk of developing LNI. Numerous retrospective series support the hypothesis that LND may be beneficial in high-risk patients (clinical T3-T4, high Fuhrman grade, presence of sarcomatoid features, or coagulative tumor necrosis). If enlarged nodes are evident at imaging or palpable during surgery, LND seems justified at any stage. However, the extent of the LND remains a matter of controversy.

CONCLUSIONS

To date, the available evidence suggests that an extended LND may be beneficial when technically feasible in patients with locally advanced disease (T3-T4) and/or unfavorable clinical and pathologic characteristics (high Fuhrman grade, larger tumors, presence of sarcomatoid features, and/or coagulative tumor necrosis). Although node-positive patients often harbor distant metastases as well, the majority of retrospective nonrandomized trials seem to suggest a possible benefit of regional LND even for this group of patients. In patients with T1-T2, clinically negative lymph nodes and absence of unfavorable clinical and pathologic characteristics, regional LND offers limited staging information and no benefit in terms of decreasing disease recurrence or improving survival.

Preoperative staging of renal cell carcinoma using magnetic resonance imaging: comparison with pathological staging

We have retrospectively assessed the accuracy of our MRI protocol on 1.0-T MRI system for preoperative staging of renal cell carcinoma using the 2002 TNM staging system and pathological staging as the gold standard. Medical records of 48 patients (mean age, 56.28 years) with 57 renal tumors were reviewed: 52 malignant renal tumors were found; most of the patients were staged T1N0M0. In our study, κ test revealed excellent agreement between all three classes of the TNM staging system.

Imaging of renal cell carcinoma: state of the art and recent advances

BACKGROUND AND AIM

Renal cell carcinoma (RCC) is the 13th most common cancer worldwide and accounts for 4% of all adult malignancies. Herein the state of the art and recent advances in cross-sectional radiological imaging applied to RCC are reviewed, including ultrasonography, computed tomography, magnetic resonance imaging, and positron emission tomography.

METHODS

Literature search of peer-reviewed papers published by October 2010.

RESULTS

In front of more conventional and widespread imaging tools, such as ultrasonography and computed tomography, an array of newer and attractive radiological modalities are under investigation and show promise to improve our ability to noninvasively detect renal tumors and its recurrences, accurately assess the extent of the disease, and reliably evaluate treatment response, particularly in the era of antiangiogenetic therapy.

CONCLUSIONS

Recent major advances in radiological imaging techniques have considerably improved our ability to diagnose, stage and follow-up RCC. Further studies are needed to evaluate the potential of most recent and still investigational imaging tools.

Physiology and pathophysiology of incidental findings detected on FDG-PET scintigraphy

A routine feature of positron emission tomography/computed tomography (PET/CT) imaging is whole-body acquisition that results in many unexpected findings identified outside of the primary region of abnormality. Furthermore, (18)F-fluorodeoxyglucose (FDG) is a marker of glycolysis and does not specifically accumulate in malignancy. Understanding the physiology and pathophysiology of normal FDG distribution and common incidental findings is therefore essential to the physician interpreting whole-body FDG-PET/CT studies. Whereas many incidental findings are benign and of limited clinical significance, others represent uncommon manifestations of the primary malignancy, second malignancies, or various clinically significant pathologic processes. Patients with a single malignancy are at greater risk of developing synchronous or metachronous second malignancies, possibly related to exposure to shared carcinogenic agents or presence of prooncogenic mutations. The decision of how to pursue an intervention on the basis of an incidental finding is generally left to clinical judgment.

[Tumours of the Kidney: CT vs. MRI. Nearly equal alternatives with minor differences]

Because of progress in imaging, the incidence of renal tumours, especially small lesions, has been rising over the last years. Therefore, imaging must be done to decide how to proceed further. But which is the most effective modality: computed tomography (CT) or magnetic resonance imaging (MRI)? From the technical point of view, the two alternatives appear to be nearly equal. Multidetector CT remains the reference standard for staging and lesion characterisation, whereas MRI is the method of choice for determining caval extension of a tumour thrombus and infiltration of the renal vein. If an accurate diagnosis cannot be specified, the remaining modality should be used complementarily.

Evolving role of magnetic resonance imaging in renal cancer imaging

MRI is an imaging modality that is used in the evaluation and treatment of renal cancer. Although less frequently used than CT, MRI is useful in several aspects of renal cancer evaluation and may have some advantages. MRI has shown promising results for renal cancer staging (especially determination of vascular invasion by tumor), in differentiating malignant from benign complex cystic renal lesions, and in the treatment and follow-up of minimally invasive ablative therapies for renal cancer. In addition, new research shows promise for novel applications of MRI. Herein we review the evolving of MRI in renal cancer imaging.

Hereditary causes of kidney tumours

BACKGROUND

In most cases of renal cell carcinoma there is no family history of renal cancer and no hereditary cause of the disease. Hereditary renal cancer accounts for about 2-4% of cases. Recognition of this subgroup by clinicians is important because of the possibility of severe medical consequences for patients and their relatives.

MATERIALS AND METHODS

We review the latest data about different genetic conditions characterized by an increased risk of developing renal cancer and we formulate tools to recognize high-risk families.

RESULTS

In general, a positive family history, young age at diagnosis of renal cancer, multiple and/or bilateral renal tumours and combined occurrence of different histological types of renal tumours should raise suspicion of a hereditary renal tumour syndrome. In addition, the presence of specific extrarenal symptoms in patients could assist in differentiating between tumour syndromes.

CONCLUSIONS

A detailed medical and family history, along with physical examination are key factors to diagnose hereditary renal cancer syndromes. When a genetic predisposition for renal cancer is suspected, referral to a Family Cancer Clinic is warranted to initiate genetic examination and counselling on preventive options.

Important aspects of organ-preserving surgery for renal tumors: indications, new standards, and oncological outcomes

INTRODUCTION

Organ-preserving surgery for renal tumors has become more common over the past two decades. At first, part of the kidney, rather than all of it, was resected only if there was an absolute indication for doing so, i.e., if the tumor was located in an anatomically or functionally solitary kidney or if renal failure was already present. Now that favorable oncological outcomes have been demonstrated, renal tumors are increasingly often removed with only partial resection of renal tissue even when the indications are less stringent, including when the other kidney is healthy.

METHODS

The indications for, and oncological outcomes of, partial renal resection are presented and discussed on the basis of a selective literature search of Medline as well as the guidelines of the European Association of Urologists (EAU).

RESULTS AND CONCLUSIONS

The EAU, in its new guidelines for renal cell carcinoma, recommends partial renal resection as the standard treatment for tumors less than 4 cm in size that are wholly contained within one kidney when the other kidney is healthy. This practice yields comparable outcomes to those of nephrectomy, with tumor-specific five-year survival rates exceeding 90%. In major urological centers, partial resection is favored even for tumors larger than 4 cm, as long as they are in a favorable location. Nonetheless, the estimated rate of nephrectomy for tumors less than 4 cm in size currently remains very high in Germany, as it does in American studies, even though the organ-preserving resection of such small tumors usually results in cure.

When do we need contrast-enhanced CT in patients with vague urinary system findings on unenhanced CT?

Determination of renal neoplasms, hematoma, infarct, urinoma, cysts, and pyelonephritis may require contrast material administration following unenhanced CT in patients with flank pain. In this pictorial review, we aimed to clarify when contrast material administration is needed following vague urinary system findings on unenhanced CT.