The value of real-time contrast-enhanced ultrasound combined with CT enhancement in the differentiation of subtypes of renal cell carcinoma

Renal cell carcinoma of the native kidney in renal transplant recipients: case report and literature review

Kidney transplant recipients (KTRs) carry an elevated risk of cancer-related mortality. The cumulative incidence of de novo post-transplant malignancy (DPTM) reaches 10% at 10 years, with renal cell carcinoma (RCC) arising in native kidneys being the predominant urologic malignancy. This study presents three KTRs who developed native kidney RCC 6-15 years post-transplantation. Notably, Case 1 demonstrated a 14.7 cm mass at diagnosis, secondary to non-adherence to protocol-based native kidney surveillance. Histopathological confirmation of RCC was established in all cases through ISUP/WHO-graded surgical specimens and immunophenotypic profiling. KTRs exhibit elevated native kidney RCC risk, often with nonspecific clinical presentations. Our findings emphasize the critical role of systematic imaging protocols, particularly ultrasonography and contrast-enhanced ultrasound (CEUS), in early tumor detection. Implementing these strategies may improve survival and reduce disease burden in this high-risk population.

Computed tomography and magnetic resonance imaging characteristics of renal cell carcinoma: Differences between subtypes and clinical evaluation

This review discusses the evaluation of renal cell carcinoma (RCC) subtypes using computed tomography (CT) and magnetic resonance imaging (MRI). RCC is a malignancy with different histopathological subtypes, constituting approximately 90% of adult kidney tumors. It has been reported that these subtypes show significant differences in terms of clinical behavior, treatment response, and prognosis. In the study, CT and MRI findings of subtypes such as clear cell RCC (ccRCC), papillary RCC (pRCC), chromophobe RCC (chRCC), medullary RCC (mRCC), collecting duct RCC (cdRCC), and multiloculated cystic RCC (mcRCC) were compared. It was stated that CT is the first-choice imaging method in the staging and surgical planning of RCC and provides detailed information about the tumor size, vascularity, and metastatic spread. On the other hand, it has been emphasized that MRI allows better characterization of RCC subtypes with its soft-tissue resolution and contrast agent usage advantage. The study draws attention to the different imaging features of each subtype and details the role of these findings in the clinical decision-making process. It has been stated that ccRCC exhibits intense contrast enhancement and rapid washout pattern in the corticomedullary phase on CT and appears hyperintense on T2A and hypointense on T1 weighted imaging (T1A) on MRI. It has been stated that pRCC has hypovascular features, has lower contrast enhancement, and has homogeneous borders. It has been stated that chRCC has a less vascular structure and exhibits moderate contrast enhancement in the corticomedullary phase. It has been reported that mRCC has invasive features and is usually diagnosed at an advanced stage while cdRCC has a very aggressive clinical course. It has been stated that mcRCC contains distinct cystic areas between the septa, has a well-circumscribed structure, and generally has a low malignancy potential. As a result, it has been stated that detailed evaluation of CT and MRI findings of RCC subtypes plays a critical role in the diagnosis, treatment, and prognosis of these subtypes. It has been emphasized that the findings presented in this study will contribute to the development of more targeted treatment approaches in RCC management.

Evaluation of Renal Masses Using Contrast-Enhanced Ultrasound with Sonovue and Sonazoid

OBJECTIVE

To explore the differences between SonoVue and Sonazoid contrast-enhanced ultrasound (CEUS) in evaluating enhancement features of renal masses and determine the diagnostic value of CEUS in clear cell renal cell carcinoma (ccRCC).

METHODS

A total of 57 eligible patients were enrolled and divided into the ccRCC, papillary renal cell carcinoma (pRCC), non-ccRCC and non-pRCC malignancy groups, and benign mass groups based on their postsurgical histopathologic diagnosis. The enhancement features of renal masses following SonoVue and Sonazoid CEUS in each group were analyzed. Diagnostic efficiencies of SonoVue and Sonazoid CEUS for ccRCC and non-ccRCC were determined.

RESULTS

There were no significant differences in the enhancement features of renal masses with SonoVue and Sonazoid imaging in the four groups (p > .05). Both SonoVue CEUS and Sonazoid CEUS showed good diagnostic performance for the differential diagnosis of ccRCC and non-ccRCC, with sensitivities of 88.6% and 85.7%, specificities of 76.5% and 88.2%, accuracies of 84.6% and 86.5%, positive predictive values of 88.6% and 93.8%, and negative predictive values of 76.5% and 75%, respectively. There were no statistically significant differences in any of the diagnostic performance indices between the two methods (p > .05).

CONCLUSION

The CEUS features of SonoVue and Sonazoid in evaluating renal masses were similar in the vascular phase. Both SonoVue and Sonazoid CEUS showed good diagnostic performance for the differential diagnosis of ccRCC and non-ccRCC.

Diagnostic value of contrast-enhanced CT in clear cell renal cell carcinoma: a systematic review and meta-analysis

OBJECTIVE

Contrast-enhanced computed tomography (CECT) improves lesion contrast with surrounding tissues through the injection of contrast agents. This enhancement allows for more precise lesion characterization, aiding in the early diagnosis of clear cell renal cell carcinoma (ccRCC). This meta-analysis aims to assess the diagnostic efficacy of CECT in ccRCC and to provide an ideal imaging examination method for the preoperative diagnosis of ccRCC.

METHODS

We conducted a comprehensive search across six major online databases: PubMed, Web of Science, Cochrane Library, WANFANG DATA, China National Knowledge Infrastructure, and Chinese BioMedical Literature Database (CBM). The objective was to collate and analyze studies that evaluate the diagnostic utility of CECT in the identification of ccRCC. Meta-disc 1.4 and Stata 16.0 were used to conduct a meta-analysis and evaluate the diagnostic accuracy of CECT for ccRCC.

RESULTS

The meta-analysis included 17 relevant studies investigating the diagnostic value of CECT for ccRCC. The combined sensitivity and specificity of CECT were 0.88 (95% confidence interval: 0.83-0.91) and 0.82 (95%CI: 0.75-0.87), respectively. Positive diagnostic likelihood ratio = 4.87 (95%CI: 3.47-6.84), negative diagnostic likelihood ratio = 0.15 (95%CI: 0.11-0.21), and diagnostic odds ratio = 32.67 (95%CI: 18.21-58.61). In addition, the area under the ROC curve was 0.92 (95%CI: 0.89-0.94), indicating that CECT has a decent discriminative ability in diagnosing ccRCC.

CONCLUSIONS

CECT is recognized as a highly effective imaging tool for diagnosing ccRCC. It provides valuable guidance in the preoperative assessment and planning of surgical strategies for patients with ccRCC.

Qualitative and quantitative assessment of non-clear cell renal cell carcinoma using contrast-enhanced ultrasound

BACKGROUND

Non-clear cell renal cell carcinoma (nccRCC) represents a rare form of renal cell carcinoma (RCC) in the clinic. It is now understood that contrast-enhanced ultrasound (CEUS) exhibits diverse manifestations and can be prone to misdiagnosis. Therefore, summarizing the distinctive features of contrast-enhanced ultrasonography is essential for differentiation from ccRCC.

OBJECTIVE

This study aims to evaluate the diagnostic efficacy of qualitative and quantitative CEUS in diagnosing nccRCC to enhance our understanding of this condition.

METHODS

We conducted a retrospective analysis of 21 patients with confirmed nccRCC following surgery and assessed the characteristic conventional ultrasound and CEUS imaging features. The paired Wilcoxon signed-rank sum test was employed to compare differences in CEUS time-intensity curve (TIC) parameters between the lesions and the normal renal cortex.

RESULTS

Routine ultrasound revealed the following primary characteristics in the 21 nccRCC cases: hypoechoic appearance (10/21, 47.6%), absence of liquefaction (18/21, 66.7%), regular shape (19/21, 90.5%), clear boundaries (21/21, 100%), and absence of calcification (17/21, 81%). Color Doppler flow imaging (CDFI) indicated a low blood flow signal (only 1 case of grade III). Qualitative CEUS analysis demonstrated that nccRCC predominantly exhibited slow progression (76.1%), fast washout (57%), uniformity (61.9%), low enhancement (71.5%), and ring enhancement (61.9%). Quantitative CEUS analysis revealed that parameters such as PE, WiAUC, mTTI, WiR, WiPI, WoAUC, WiWoAUC, and WOR in the lesions were significantly lower than those in the normal renal cortex (Z=-3.980, -3.563, -2.427, -3.389, -3.980, -3.493, -3.528, -2.763, P < 0.001, < 0.001, = 0.015, = 0.001, < 0.001, < 0.001, < 0.001, = 0.006). However, there were no significant differences in RT, TTP, FT, or QOF (all P > 0.05).

CONCLUSION

nccRCC exhibits distinctive CEUS characteristics, including slow progression, fast washout, low homogeneity enhancement, and ring enhancement, which can aid in distinguishing nccRCC from ccRCC.

Predictive Model of CK7 Expression in Patients With Clear Cell Renal Cell Carcinoma by Combined Multimodal Ultrasound Diagnostic Techniques: A Retrospective Study

OBJECTIVE

The aim of the work described here was to develop and validate a predictive model for cytokeratin 7 (CK7) expression in clear cell renal cell carcinoma (ccRCC) patients by combining multimodal ultrasound diagnostic techniques.

METHODS

This retrospective study enrolled 157 surgically confirmed ccRCC patients. All patients underwent pre-operative multimodal ultrasound diagnostic examinations, including B-mode ultrasound (US), color Doppler flow imaging (CDFI) and contrast-enhanced ultrasound (CEUS). The patients were randomly divided into a training group (103 cases) and a testing group (54 cases). Univariate and multivariate logistic regression analyses were performed in the training group to identify independent indicators associated with CK7 positivity. These indicators were included in the predictive model. Receiver operating characteristic (ROC) curves and calibration curves were used to evaluate the model's discriminative ability and accuracy. Decision curve analysis (DCA) and nomogram visualization were used to assess the clinical utility of the predictive model.

RESULTS

Univariate logistic regression analysis revealed that US and CDFI observations were not correlated with CK7 expression and could not predict it. Multivariate logistic regression analysis identified age (odds ratio [OR] = 0.953, 95% confidence interval [CI]: 0.909-0.999), wash-in pattern (OR = 0.180, 95% CI: 0.063-0.513) and enhancement homogeneity (OR = 11.610, 95% CI: 1.394-96.675) as independent factors related to CK7 positivity in ccRCC. Incorporating these variables into the predictive model resulted in areas under the receiver operating characteristic curve of 0.812 (95% CI: 0.711-0.913) for the training group and 0.792 (95% CI: 0.667-0.924) for the testing group. The calibration curve and DCA revealed that the model had good accuracy and clinical utility of the model.

CONCLUSION

The combination of multimodal ultrasound diagnostic techniques in constructing a predictive model for CK7 expression in ccRCC patients has significant predictive value.

EFSUMB Technical Review - Update 2023: Dynamic Contrast-Enhanced Ultrasound (DCE-CEUS) for the Quantification of Tumor Perfusion

Dynamic contrast-enhanced ultrasound (DCE-US) is a technique to quantify tissue perfusion based on phase-specific enhancement after the injection of microbubble contrast agents for diagnostic ultrasound. The guidelines of the European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB) published in 2004 and updated in 2008, 2011, and 2020 focused on the use of contrast-enhanced ultrasound (CEUS), including essential technical requirements, training, investigational procedures and steps, guidance regarding image interpretation, established and recommended clinical indications, and safety considerations. However, the quantification of phase-specific enhancement patterns acquired with ultrasound contrast agents (UCAs) is not discussed here. The purpose of this EFSUMB Technical Review is to further establish a basis for the standardization of DCE-US focusing on treatment monitoring in oncology. It provides some recommendations and descriptions as to how to quantify dynamic ultrasound contrast enhancement, and technical explanations for the analysis of time-intensity curves (TICs). This update of the 2012 EFSUMB introduction to DCE-US includes clinical aspects for data collection, analysis, and interpretation that have emerged from recent studies. The current study not only aims to support future work in this research field but also to facilitate a transition to clinical routine use of DCE-US.

Case Report: The ultrasound features of acquired cystic disease-associated renal cell carcinoma: a case series

Background

Acquired cystic disease-associated renal cell carcinoma (ACD-RCC) is a new subtype listed by the 2016 World Health Organization (WHO) classification, which occurred in end-stage renal disease (ESRD) patients. This study will present the imaging characteristics of the four cases diagnosed with ACD-RCC. Ultrasound is expected to help detect abnormalities early in the follow-up of patients on regular dialysis, allowing patients to receive early treatment.

Case presentation

We searched the pathology database of our hospital for all inpatients diagnosed with ACD-RCC between January 2016 and May 2022. Pathology, ultrasound, and radiology readings are performed by experienced physicians with the title of attending physician or higher. Four cases were included in this study, all of whom were male, aged from 17 to 59. Two cases suffered from ACD-RCC in both kidneys, and kidney nephrectomies were performed. One case underwent renal transplantation, whose creatinine was back to normal, and the rest were on hemodialysis. On the pathological images, heteromorphic cells and oxalate crystals can be seen. Both ultrasound and enhanced CT showed an enhancement of the solid component of the occupancy. We followed up with outpatient and telephone visits.

Conclusion

In clinical work, ACD-RCC should be considered when the mass appears in the background of multiple cysts in the kidney in patients with ESRD. A timely diagnosis will help with treatment and prognosis.

Long Non-Coding RNAs as Novel Biomarkers in the Clinical Management of Papillary Renal Cell Carcinoma Patients: A Promise or a Pledge?

Papillary renal cell carcinoma (pRCC) represents the second most common subtype of renal cell carcinoma, following clear cell carcinoma and accounting for 10-15% of cases. For around 20 years, pRCCs have been classified according to their mere histopathologic appearance, unsupported by genetic and molecular evidence, with an unmet need for clinically relevant classification. Moreover, patients with non-clear cell renal cell carcinomas have been seldom included in large clinical trials; therefore, the therapeutic landscape is less defined than in the clear cell subtype. However, in the last decades, the evolving comprehension of pRCC molecular features has led to a growing use of target therapy and to better oncological outcomes. Nonetheless, a reliable molecular biomarker able to detect the aggressiveness of pRCC is not yet available in clinical practice. As a result, the pRCC correct prognosis remains cumbersome, and new biomarkers able to stratify patients upon risk of recurrence are strongly needed. Non-coding RNAs (ncRNAs) are functional elements which play critical roles in gene expression, at the epigenetic, transcriptional, and post-transcriptional levels. In the last decade, ncRNAs have gained importance as possible biomarkers for several types of diseases, especially in the cancer universe. In this review, we analyzed the role of long non-coding RNAs (lncRNAs) in the prognosis of pRCC, with a particular focus on their networking. In fact, in the competing endogenous RNA hypothesis, lncRNAs can bind miRNAs, resulting in the modulation of the mRNA levels targeted by the sponged miRNA, leading to additional regulation of the target gene expression and increasing complexity in the biological processes.