Tubulocystic renal cell carcinoma: Case report and literature review

To optimize the diagnosis and treatment of Tubulocystic renal cell carcinoma, we present our experience with a case of it and review the literature. Tubulocystic renal cell carcinoma (TRCC) is a rare subtype of renal carcinoma with distinctive histological and molecular characteristics. This study provides a comprehensive analysis of TRCC, focusing on its pathological features, diagnostic criteria, and potential molecular mechanisms. The findings highlight the unique histological architecture and biological behavior of TRCC, distinguishing it from other renal cell carcinomas. Advanced imaging techniques and molecular biomarkers play a pivotal role in its accurate diagnosis.

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.

A Renal Cyst Invaded by Infiltrating Renal Cell Carcinoma With Multiple Hypermetabolic Bone Metastases as the Initial Presentation

ABSTRACT

Cystic renal cell carcinoma (RCC) refers to an indolent version of RCC composed predominantly of cysts, and it is associated with good prognosis. We showed the FDG PET/CT findings in a patient with multiple hypermetabolic bone metastases presenting with pain in the left shoulder and upper abdomen, who was later found to have cystic RCC. FDG PET/CT demonstrated hypermetabolic bone lesions and slight thickening of the renal cyst wall with light metabolism. This report indicates the risk of misdiagnosing cystic RCC as a renalcyst.

Clinicopathological features of non-conventional renal cell carcinoma histological subtypes: Learning points from a large contemporary series spanning over three decades

Purpose

To perform a retrospective review of the clinicopathological features of patients with conventional and non-conventional renal cell carcinoma (cRCC and ncRCC).

Materials and Methods

A large prospectively maintained uro-oncological registry was accessed to extract clinicopathological data of patients diagnosed with renal tumors who subsequently underwent nephrectomy from 1990–2019. Demographics and operative parameters were extracted. Analyses of overall survival (OS) and cancer-specific survival (CSS) were performed using the Kaplan–Meier method. Cox proportional-hazards analysis was used to identify risk factors which influenced survival.

Results

There were a total of 1,686 consecutive nephrectomies which was retrieved, with 1,286 cRCC and 400 ncRCC. The commonest ncRCC subtypes were papillary (n=198, 11.7%), clear cell papillary (n=50, 3.0%) and chromophobe (n=49, 2.9%) RCC. Kaplan–Meier estimates of OS were higher in cRCC (0.74; 95% confidence interval [CI], 0.71–0.78) than ncRCC (hazard ratio, 1.47; 95% CI, 1.16–1.87). Among individual subtypes, chromophobe RCC had the highest 5-year OS (0.90; 95% CI, 0.79–1.0). Among ncRCC subtypes, acquired cystic RCC demonstrated the highest association with end-stage renal failure and hypertension, with the highest CSS. MiT family translocation RCC had the youngest mean age at presentation (45.6±12.8 y) and excellent CSS. Factors associated with increased OS in the entire cohort included shorter operative time, partial nephrectomy and lower tumor stages.

Conclusions

This study provides a comprehensive contemporary overview of ncRCCs which are yet poorly characterized, in comparison to cRCCs. Data from this study would contribute towards tailored patient counseling and healthcare resource planning.

A Comprehensive Commentary on the Multilocular Cystic Renal Neoplasm of Low Malignant Potential: A Urologist’s Perspective

Multilocular cystic renal neoplasm of low malignant potential (MCRNLMP) is a cystic renal tumor with indolent clinical behavior. In most of cases, it is an incidental finding during the examination of other health issues. The true incidence rate is estimated to be between 1.5% and 4% of all RCCs. These lesions are classified according to the Bosniak classification as Bosniak category III. There is a wide spectrum of diagnostic tools that can be utilized in the identification of this tumor, such as computed tomography (CT), magnetic resonance (MRI) or contrast-enhanced ultrasonography (CEUS). Management choices of these lesions range from conservative approaches, such as clinical follow-up, to surgery. Minimally invasive techniques (i.e., robotic surgery and laparoscopy) are preferred, with an emphasis on nephron sparing surgery, if clinically feasible.

Multilocular Cystic Renal Neoplasm of Low Malignant Potential: A Case Report and Literature Review

Multilocular cystic renal neoplasm of low malignant potential (MCRNLMP) is a rare subtype of renal cell carcinoma that has a favorable outcome. Most cases of MCRNLMP usually present as distinct multilocular cystic lesions; however, they may appear as small complicated cysts with hemorrhagic components. Herein, we present a case of MCRNLMP and provide a review of the literature.

CT and MRI findings of cystic renal cell carcinoma: comparison with cystic collecting duct carcinoma

BACKGROUND

Cystic renal cell carcinoma (CRCC) and cystic collecting duct carcinoma (CCDC) share similar oncogeni and some imaging findings. The aim of this study was to characterize the clinical and CT imagings features of CRCC and CCDC.

METHODS

Thirty-three patients with CRCC and thirteen patients with CCDC with pathologically proven were retrospectively studied. Tumor characteristics were assessed.

RESULTS

On CT imaging, 33 patients(100 %) with CRCC and 13 patients(100 %) with CCDC, tumors calcifications (8 vs. 9, P < 0.0001), had a clear boundary (capsule sign, 30 vs. 2, P < 0.0001), infiltrative appearance (1 vs. 13, P < 0.0001), exogenous appearance (29 vs. 3, P < 0.0001), invaded the renal pelvis or ureter (1 vs. 10, P < 0.0001), hemorrhage (1 vs. 10, P < 0.0001), had retroperitoneal lymph node or distant metastasis (2 vs. 10, P < 0.0001), thickened enhancing internal septations (31 vs. 2, P < 0.0001), and mural soft-tissue nodules (21 vs. 1, P < 0.0001). On MR imaging,13 patients(39 %) with CRCC and 4 patients(31 %) with CCDC, all CRCCs appeared hypointense on T1-weighted images and hyperintense on T2-weighted images, however, all CCDCs appeared hypointense on T1-weighted images and hypointense on T2-weighted images(P < 0.0001). 33 patients with CRCC, they were all alive from3 years to 10 years follow-up, however, 13 patients with CCDC, of which 11 patients were able to be followed up, and 9 patients expired within 5 years of the initial diagnosis and the others are currently still alive.

CONCLUSIONS

Distinguishing features of CRCC and CCDC included calcifications, capsule signs, infiltrative appearance, metastasis, internal septations, mural nodules and signal on CT or MR images. These imaging features may help in differentiating the two renal tumor types.

Contrast-enhanced Ultrasound for Diagnosis of Renal Cystic Mass

BACKGROUND

Cystic Renal Cell Carcinoma (CRCC) is often challenging to differentiate from complex cysts with sonographic manifestations of renal carcinoma. Contrast-Enhanced Ultrasound (CEUS) is a new technology, and its clinical utility in the diagnosis of renal cystic mass has not been established.

OBJECTIVE

To analyze the characteristics of CEUS of renal cystic masses and to explore the clinical significance and value of CEUS in the diagnosis of CRCC.

METHODS

This study was a retrospective study. A total of 32 cystic masses from January 2018 to December 2019 were selected. The images of conventional ultrasound (US) and CEUS were confirmed via surgical pathology. The routine US was used to observe the location, shape, size, boundary, cyst wall, internal echo, and blood supply of each cystic mass. CEUS observed contrast enhancement of the cyst wall, cystic septa, and solid nodules of cystic masses.

RESULTS

There were 26 cases of CRCC, 5 cases of renal cysts, and 1 case of renal tuberculosis. The enhancement pattern, degree of enhancement, and pseudocapsular sign by CEUS in benign and malignant masses had statistically significant differences (P<.05). In the diagnosis of CRCC, the sensitivity, specificity, accuracy, positive predictive value, and negative predictive value were 92.3%, 83.3%, 90.6%, 96.0%, and 71.4% for CEUS; 57.6%, 66.7%, 59.3%, 88.2%, and 26.7% for conventional US, respectively. CEUS had a higher sensitivity and accuracy than the conventional US (P<.05). However, the diagnostic specificity, positive predictive value, and negative predictive value of the two methods were not significantly different (P>.05).

CONCLUSION

CEUS is more accurate in the diagnosis of renal cystic masses, and it can be used as an effective imaging method.

The Incidental Renal Mass- Update on Characterization and Management

Renal masses are commonly encountered on cross-sectional imaging examinations performed for nonrenal indications. Although most can be dismissed as benign cysts, a subset will be either indeterminate or suspicious; in many cases, imaging cannot be used to reliably differentiate between benign and malignant masses. On-going research in defining characteristics of common renal masses on advanced imaging shows promise in offering solutions to this issue. A recent update of the Bosniak classification (used to categorize cystic renal masses) was proposed with the goals of decreasing imaging follow-up in likely benign cystic masses, and therefore avoiding unnecessary surgical resection of such masses.

A MEST up classification? Review of the re-classification of mixed epithelial and stromal tumor and adult cystic nephroma for the abdominal radiologist

Mixed epithelial and stromal tumor (MEST) and the tumor formerly known as adult cystic nephroma (ACN) are uncommon renal tumors that have historically been described as separate entities in terms of histologic and imaging findings. However, these entities share many epidemiologic, radiologic, and pathologic features. While recent surgical and pathological literature has supported classifying MEST and ACN within the same tumor family, most radiologists and radiology texts continue to describe MEST and ACN as separate entities.

Prolonged natural history of a cystic renal cell carcinoma: A case report

We describe the successful management of a 50-year male who presented with gradually progressive abdominal swelling for over 20 years. The highlights of the case are giant renal mass occupying the whole abdomen and the absence of metastasis despite a long history.

Protocol Optimization for Renal Mass Detection and Characterization

Renal masses increasingly are found incidentally, largely due to the frequent use of medical imaging. Computed tomography (CT) and MR imaging are mainstays for renal mass characterization, presurgical planning of renal tumors, and surveillance after surgery or systemic therapy for advanced renal cell carcinomas. CT protocols should be tailored to different clinical indications, balancing diagnostic accuracy and radiation exposure. MR imaging protocols should take advantage of the improved soft tissue contrast for renal tumor diagnosis and staging. Optimized imaging protocols enable analysis of imaging features that help narrow the differential diagnoses and guide management in patients with renal masses.

Bosniak Classification of Cystic Renal Masses, Version 2019: An Update Proposal and Needs Assessment

Cystic renal cell carcinoma (RCC) is almost certainly overdiagnosed and overtreated. Efforts to diagnose and treat RCC at a curable stage result in many benign neoplasms and indolent cancers being resected without clear benefit. This is especially true for cystic masses, which compared with solid masses are more likely to be benign and, when malignant, less aggressive. For more than 30 years, the Bosniak classification has been used to stratify the risk of malignancy in cystic renal masses. Although it is widely used and still effective, the classification does not formally incorporate masses identified at MRI or US or masses that are incompletely characterized but are highly likely to be benign, and it is affected by interreader variability and variable reported malignancy rates. The Bosniak classification system cannot fully differentiate aggressive from indolent cancers and results in many benign masses being resected. This proposed update to the Bosniak classification addresses some of these shortcomings. The primary modifications incorporate MRI, establish definitions for previously vague imaging terms, and enable a greater proportion of masses to enter lower-risk classes. Although the update will require validation, it aims to expand the number of cystic masses to which the Bosniak classification can be applied while improving its precision and accuracy for the likelihood of cancer in each class.

Active Surveillance of Small (< 4 cm) Bosniak Category 2F, 3, and 4 Renal Lesions: What Happens on Imaging Follow-Up?

OBJECTIVE. The purpose of this study was to determine the percentage of small (< 4 cm) Bosniak category 2F, 3, and 4 lesions that regress during active surveillance. MATERIALS AND METHODS. In this retrospective study, a hospital database was searched from January 1, 2005, through September 9, 2017, for small (< 4 cm) Bosniak category 2F, 3, and 4 lesions studied with initial and follow-up unenhanced and contrast-enhanced CT or MRI. Prospective Bosniak categories were recorded. Two blinded radiologists retrospectively reassigned Bosniak categories to the initial and last follow-up studies. Interreader variability was analyzed. Rates of stability, regression, and progression were calculated and stratified by size. Logistic regression was used to assess the effects of lesion size, lesion growth, and duration of follow-up on the change in Bosniak categories. RESULTS. The search identified 123 patients (85 men, 38 women) with 138 renal lesions (according to the blinded readings, 83 Bosniak category 2F, 37 category 3, and 18 category 4) and followed for 1-12.3 years (median, 2.7 years). Fifty-one percent (70/138) of the lesions were smaller than 2 cm. Eighty-eight percent (73/83) of category 2F lesions were downgraded or remained stable. Forty-five percent (25/55) of category 3 or 4 lesions were downgraded to 2F or lower. Kappa values were 0.94 between the two readers and 0.72-0.76 between the readers and the prospective Bosniak categories. There was no association between initial size, change in size, or duration of follow-up and change in Bosniak category. CONCLUSION. Approximately one-half of small (< 4 cm) Bosniak category 3 and 4 cystic renal lesions were downgraded, and the majority (88%) of small Bosniak category 2F lesions regressed or remained stable during active surveillance. Therefore, small size should be a consideration for conservative management.

Superb microvascular imaging is a rational choice for accurate Bosniak classification of renal cystic masses

OBJECTIVE

Bosniak classification system provides a fine imaging evaluation for the malignant cystic renal masses. Superb microvascular imaging (SMI) is a new ultrasonic technique which apply advanced clutter suppression to reflect microflow information. The aim of this study was to evaluate the performance of ultrasound Bosniak classification aided by SMI in diagnosis of cystic renal masses.

METHODS

By comparing with contrast-enhanced ultrasound (CEUS) and pathology, we evaluated the sensitivity, specificity and accuracy of conventional ultrasound and SMI combination in the diagnosis of renal cystic masses.

RESULTS

Color Doppler Flow image (CDFI) and SMI had significant difference in evaluation the blood flow and Bosniak classification for cystic renal mass of IIf, III and IV (p = 0.020). SMI was consistent with CEUS for cystic renal mass Bosniak classification of IIf, III and IV. Although, CEUS had highest sensitivity of 97.4%, SMI had the highest area under curve in differential diagnosis malignance from benign masses [area under curve = 0.869 (0.743 - 0.995), p < 0.001].

CONCLUSION

SMI can display better in observing blood flow in septa and solid structures of renal cystic lesions compared with CDFI, thus, it can perform more accurate Bosniak classification for renal cystic mass. SMI and CEUS are consistent in Bosniak classification. Bosniak classification aided by SMI maybe an accurate non-invasive ultrasonic examination in distinguishing benign and malignant renal cystic lesions.

ADVANCES IN KNOWLEDGE

Conventional ultrasound had limited ability to distinguish malignance in Bosniak classifications IIf and III. SMI can display better in observing blood flow in septa and solid structures of renal cystic lesions compared with CDFI.

Uncommon malignant renal tumors and atypical presentation of common ones: a guide for radiologists

OBJECTIVE

While the typical imaging features of the more common RCC subtypes have previously been described, they can at times have unusual, but distinguishing features. Rarer renal tumors span a broad range of imaging features, but they may also have characteristic presentations. We review the key imaging features of atypical presentations of malignant renal tumors and uncommon malignant renal tumors.

CONCLUSION

Renal tumors have many different presentation patterns, but knowledge of the distinguishing MR and CT features can help identify both atypical presentation of common malignancies and uncommon renal tumors.

Classification and Diagnosis of Cystic Renal Tumors: Role of MR Imaging Versus Contrast-Enhanced Ultrasound

Superior soft tissue and contrast resolution of MR imaging benefits sensitivity to kidney cyst features and classification, which may have an impact on patient management and outcomes. Contrast-enhanced ultrasound (CEUS) may have nearly similar sensitivity for detection of cyst features yet is dependent on patient body habitus and adequacy of visualization windows for the kidneys, which does not have the same impact on MR imaging results. Both MR imaging and CEUS may provide superior kidney cyst assessment compared with contrast-enhanced CT; however, further research is needed, particularly for the identification of role of CEUS.

Contemporary update on imaging of cystic renal masses with histopathological correlation and emphasis on patient management

This article presents an updated review of cystic renal mass imaging. Most cystic renal masses encountered incidentally are benign and can be diagnosed confidently on imaging and require no follow-up. Hyperattenuating masses discovered at unenhanced or single-phase enhanced computed tomography (CT) measuring between 20-70 HU are indeterminate and can be further investigated first by using ultrasound and, then with multi-phase CT or magnetic resonance imaging (MRI); as the majority represent haemorrhagic/proteinaceous cysts (HPCs). Dual-energy CT may improve differentiation between HPCs and masses by suppressing unwanted pseudo-enhancement observed with conventional CT. HPCs can be diagnosed confidently when measuring >70 HU at unenhanced CT or showing markedly increased signal on T1-weighted imaging. Although the Bosniak criteria remains the reference standard for diagnosis and classification of cystic renal masses, histopathological classification and current management has evolved: multilocular cystic renal cell carcinoma (RCC) has been reclassified as a cystic renal neoplasm of low malignant potential, few Bosniak 2F cystic masses progress radiologically during follow-up; RCC with predominantly cystic components are less aggressive than solid RCC; and Bosniak III cystic masses behave non-aggressively. These advances have led to an increase in non-radical management or surveillance of cystic renal masses including Bosniak 3 lesions. Tubulocystic RCC is a newly described entity with distinct imaging characteristics, resembling a pancreatic serous microcystadenoma. Other benign cystic masses including: mixed epithelial stromal tumours (MEST) are now considered in the spectrum of cystic nephroma and angiomyolipoma (AML) with epithelial cysts (AMLEC) resemble a fat-poor AML with cystic components.

Tubulocystic renal cell carcinoma: a review of literature focused on radiological findings for differential diagnosis

Tubulocystic renal cell carcinoma (TC-RCC) has been classified as an independent subtype according to the 2016 World Health Organization (WHO) classification. It is a rare subtype that predominantly affects men. Although few in number, radiological imaging reports have suggested that TC-RCC is characterized by multilocular cystic lesions, which are categorized as the Bosniak classification II-IV, with signature pathological characteristics comprising numerous small cysts or a tubular structure. The Bosniak classification system facilitates patient management; however, the differentiation of cystic tumors exhibiting similar imaging findings remains impossible; in fact, the differentiation of multilocular cystic RCC, adult cystic nephroma, and mixed epithelial and stromal tumor remains challenging. This review aims to discuss TC-RCC with a focus on implications of radiological findings in the differential diagnosis of TC-RCC.

Correlation of computed tomography characteristics of cystic renal cell carcinoma with histopathology

Background

Renal cysts are common incidental findings in computed tomography (CT) of the abdomen and range from benign to cystic renal cell carcinoma (RCC). Cystic RCC has various pathology, clinical prognosis, and treatment options.

Objectives

To compare preoperative CT of cystic RCC with histopathology.

Methods

Preoperative CT of histopathologically proven cystic RCCs were retrospectively reviewed in this single-center cross-sectional observational study. Two investigators recorded consensus CT features for each cystic RCC. The means of descriptive continuous data were calculated. A chi-square test, Fisher’s exact test, or an ANOVA were used for compare the frequency of findings for each histopathological subtype.

Results

Of 38 cystic RCCs, 25 were clear cell RCC, 5 were papillary RCC, 4 were multilocular cystic RCC, 1 was chromophobe RCC, and 3 were mixed type/other type (papillary/chromophobe, clear cell/chromophobe, and sarcomatoid type). We classified 36 lesions as Bosniak category IV and 2 lesions as Bosniak category III. There was no significant difference in cyst attenuation in any phase. Solid attenuation of the tumors was significantly different for each type in corticomedullary and nephrogenic phases (P = 0.001 and 0.042, respectively). Clear cell RCC was enhanced the most on corticomedullary and nephrogenic phases (means 135.5 and 112.1 Hounsfield Units, respectively). Septal thickening, enhancement, and multilocularity were significantly different between subtypes, particularly in multilocular cystic RCCs (P = 0.018, 0.018, and 0.02, respectively).

Conclusion

Preoperative CT findings may help clinicians and radiologists to predict tumor subtypes and aid treatment planning.

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.

Retrospective evaluation of ultrasound-indeterminate renal multilocular cystic masses by using neutrophil-lymphocyte ratio and computed tomography

PURPOSE

To evaluate the clinical usefulness of neutrophil-lymphocyte ratio (NLR) in differentiating the ultrasound-indeterminate renal multilocular cystic masses (RMCM) in comparison with computed tomography (CT) and whether NLR has additional benefits to CT on sensitivity of detecting the malignant.

MATERIALS AND METHODS

Overall, 93 patients who underwent normal ultrasound with a conclusion of indeterminate RMCM were examined by NLR and CT within 30 days before surgery or follow-up from March to September 2014 at PLA General Hospital and enrolled in this retrospective study. Logistic regression model was performed to find independent predictors for differentiating true nature of RMCM; differences in the validity parameters and diagnostic power of CT, NLR, and their combination were compared using McNemar tests and AUC model, respectively.

RESULTS

The final diagnoses of the 93 patients consisted of 36 patients with benign complex cysts, 16 with multilocular cystic renal cell carcinoma, 9 with multilocular cystic nephroma, and 32 with clear cell renal cell carcinoma. Higher NLR were strongly associated with malignant masses. Multivariate logistic regression analysis revealed that NLR could be an independent predictor for differentiating true nature of these masses (OR = 3.617; 95% CI: 1.219-10.727; P = 0.020). For detecting the malignant masses, the sensitivity, specificity, and accuracy were 71.9%, 80.6%, and 75.3% for CT and 57.9%, 88.9%, and 69.9% for NLR under cutoff value of 2.31, respectively, whereas those of CT+NLR were 89.5%, 69.4%, and 81.7%. No significant difference was found between CT and NLR in sensitivity (P = 0.185), specificity (P = 0.549), and accuracy (P = 0.428). But the sensitivity of CT+NLR was significantly higher than those of CT (P = 0.002) and NLR (P<0.001), respectively; AUC model analysis indicated that CT+NLR got the largest area of 0.795 (P<0.001, 95% CI: 0.693-0.896) in comparison with those of CT (area = 0.795, P<0.001, 95% CI: 0.661-0.864) and NLR (area = 0.734, P<0.001, 95% CI: 0.631-0.836).

CONCLUSIONS

Given that NLR, under cutoff value of 2.31, had no diagnostic difference with CT in evaluating the ultrasound-indeterminate RMCM. However, combination of CT and NLR could increase the sensitivity of detecting malignant masses and acquire the best diagnostic power. Prospectively larger cohort and multicenter studies are still necessary.

The spectrum of renal cell carcinoma in adults

The spectrum of renal cell carcinoma (RCC) includes many neoplasms with distinct cytogenetics, biologic behaviors, and imaging appearances. The advent of molecular therapies targeting different tumor types, new insights into the relative roles of biopsy and surveillance for small incidental tumors, and a growing array of nephron-sparing interventions have altered management of RCC. Similarly, the role of the radiologist is changing, and it is becoming increasingly important for radiologists to familiarize themselves with the various types of RCC. This article introduces the reader to the common and uncommon recognized types of renal cell carcinoma and discusses how these neoplasms differ in imaging appearance and behavior.

Cystic renal masses

PURPOSE

The purpose of the study is to provide an update on the imaging evaluation of cystic renal masses, to review benign and malignant etiologies of cystic renal masses, and to review current controversies and future directions in the management of these lesions.

CONCLUSIONS

Cystic renal masses are relatively common in daily practice. The Bosniak classification is a time-proven method for the imaging classification and management of these lesions. Knowledge of the pathognomonic features of certain benign Bosniak 2F/3 lesions is important to avoid surgery on these lesions (e.g., localized cystic disease, renal abscess). For traditionally surgical Bosniak lesions (Classes 3 and 4), there are evolving data that risk stratification based on patient demographics, imaging size, and appearance may allow for expanded management options including tailored surveillance or ablation, along with the traditional surgical approach.

Unusual renal tumour: multilocular cystic renal cell carcinoma

Multilocular cystic renal cell carcinoma (MCRCC) is a rare presentation of renal cell carcinoma. Most patients are asymptomatic and frequently MCRCCs are detected incidentally. MCRCCs have good prognosis because of their low malignant potential. We report a case of a 39-year-old woman who presented with mild right flank pain and normal laboratory data. On imaging examinations, a Bosniak III cystic lesion was detected in the lower third of the right kidney. She underwent right partial nephrectomy and histopathology showed a multilocular cystic renal cell carcinoma Fuhrman grade 1. In this article, we also present a review of the literature on MCRCC, highlight the correlation of the pathological and imaging characteristics of these low aggressive renal lesions, and underscore the importance of their recognition to prevent unnecessary radical surgery.

Cystic renal cell carcinoma carries an excellent prognosis regardless of tumor size

INTRODUCTION

Cystic renal cell carcinoma (cystic RCC) is thought to carry an improved prognosis relative to clear cell RCC (CCRCC); however, this is based on small case series. We used a population-based tumor registry to compare clinicopathologic features and cancer-specific mortality (CSM) of cystic RCC with those of CCRCC.

MATERIALS AND METHODS

The Surveillance, Epidemiology, and End Results database was queried for all patients diagnosed and treated for cystic RCC and CCRCC between 2001 and 2010. Clinical and pathologic factors were compared using t tests and chi-square tests as appropriate. Kaplan-Meier survival analysis compared CSM differences between cystic RCC and CCRCC.

RESULTS

A total of 678 patients with cystic RCC and 46,677 with CCRCC were identified. The mean follow-up duration was 52 and 40 months, respectively. When compared with CCRCC patients, those with cystic RCC were younger (mean age 58 vs. 61 y, P < 0.001), more commonly black (22% vs. 9%, P < 0.001), and female (45% vs. 41%, P = 0.02). Cystic RCCs were more commonly T1a tumors (66% vs. 55%, P < 0.001), well differentiated (33% vs. 16%, P < 0.001), and smaller (mean size = 3.8 vs. 4.5 cm, P < 0.001). Cystic RCC was associated with a reduction in CSM when compared with CCRCC (P = 0.002). In a subset analysis, this reduction in CSM was seen only for those with T1b/T2 tumors (P = 0.01) but not for those with T1a RCCs lesions (P = 0.31).

CONCLUSIONS

We report the largest series of cystic RCC and corroborate the findings of improved CSM when compared with CCRCC for larger tumors; however, no difference was noted in smaller tumors, suggesting that tumor biology becomes more relevant to prognosis with increasing size. These data may suggest a role for active surveillance in appropriately selected patients with small, cystic renal masses.

Application of laparospic ultrasonography in surgery of small renal cell carcinoma

PURPOSE

: To assess the clinic value of application of laparospic ultrasonography (LU) in partial nephrectomy of small renal cell carcinoma.

MATERIALS AND METHODS

From 2007 to 2011, 28 small renal cell carcinoma patients in ou clinic underwent laparoscopic partial nephrectomy with LU. For comparison with preoperative conventional ultrasound and CT, we collected ultrasonic performance of the affected side kidney, renal tumor location, size, echo change, blood supply situation and the relationship with the surrounding tissue.

RESULTS

LU could more clearly show the tumor interior structure and blood supply, as well as the relationship with the surrounding tissue. It also can provided doctor assistance with real-time tumor resection, reducing operative complications.

CONCLUSIONS

LU can clearly show tumor internal structure and blood supply, which is helpful for explicit diagnosis. Moreover, it supplies accurate information for surgeons and assists surgery. Therefore LU has an important guiding value in partial nephrectomy for small renal cell carcinoma.

MRI features of renal cell carcinoma that predict favorable clinicopathologic outcomes

OBJECTIVE

The purpose of this article is to determine whether MRI features of renal cell carcinoma (RCC), such as enhancing solid component and T1 signal intensity, are associated with clinicopathologic outcomes.

MATERIALS AND METHODS

This retrospective study included 241 RCCs in 230 patients who underwent preoperative MRI, had pathologic analysis results available, and were monitored for at least 3 months. A radiologist assessed tumor features on MRI, including unenhanced T1 signal relative to renal cortex and the percentage of solid enhancing components. The electronic medical record or follow-up images were reviewed to assess for the development of local recurrence or metastases. Statistical analysis was performed to correlate imaging features at MRI with pathologic and clinical outcome.

RESULTS

The following tumor features were observed: predominantly cystic morphologic features (defined as solid component≤25%, n=33), solid component greater than 25% (n=208), T1 hypointensity (n=97), and T1 intermediate intensity or hyperintensity (n=144). Local recurrence or metastases were observed in 14 patients. Compared with T1-intermediate or -hyperintense lesions, T1-hypointense RCCs were more likely to be low stage (90.7% vs 74.3%; p=0.001) and low grade (78.9% vs 41.8%; p<0.001) and had a lower rate of recurrence or metastases (3.3% vs 8%; p=0.167). Compared with lesions with greater than 25% solid enhancement, predominantly cystic RCCs were more likely to be lower stage (93.9% vs 78.8%; p=0.053) and lower grade (94.7 vs 56.5%; p<0.001) and to have no incidence of recurrence or metastasis (0% vs 6.9%; p=0.227). RCCs that were both cystic and T1 hypointense (n=14) were lower stage (100% vs 79.6%; p=0.047) and lower grade (92.9% vs 58.1%; p=0.01) and had no recurrence or metastases on follow-up.

CONCLUSION

Cystic and T1-hypointense RCC show less-aggressive pathologic features and favorable clinical behavior.

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.

Clinicopathologic outcomes of cystic renal cell carcinoma

BACKGROUND

The purpose of this study was to describe the clinicopathologic characteristics and oncologic outcomes of patients who underwent nephrectomy for cystic renal masses.

PATIENTS AND METHODS

Using an institutional review board-approved database, we retrospectively reviewed the clinical, pathologic, radiologic, and oncologic outcome data of patients who received nephrectomy for a complex cystic renal mass.

RESULTS

Sixty-one patients were identified who received nephrectomy for a complex cystic lesion. Average age was 64 years. Thirty-nine (64%) patients were male. At the time of resection, 1 (1.6%), 3 (4.8%), 53 (86.8%), and 4 (6.5%) had a Bosniak category II, IIF, III, and IV cystic lesion, respectively. Nineteen (31.1%) patients were initially managed expectantly but underwent surgery because of progression of complexity on follow-up. Mean pathologic tumor size was 3.3 cm (range, 0.7-12 cm). Forty-eight (78.6%) of the lesions were found to be malignant. Thirty-seven (77.1%), 5 (10.4%), 4 (8.3%), and 2 (4.1%) were stage T1a, T1b, T2a, and T3a, respectively. Clear cell was the most common histologic subtype (44%), followed by papillary (21.3%), and unclassified RCC (4.9%). With a mean and median follow-up of 48.4 and 43.0 months, respectively, no patients developed a local or metastatic recurrence. All patients were alive at last follow-up.

CONCLUSION

In our series with moderate follow-up, cystic RCCs do not appear to recur or progress regardless of size, histologic subtype, or grade. These findings suggest the malignant potential of cRCCs is significantly less than solid RCCs. Further investigation is required to determine if cRCCs should be classified and managed independently from solid RCCs.

MRI phenotype in renal cancer: is it clinically relevant?

Renal cell carcinoma (RCC) is most commonly diagnosed as an incidental finding on cross-sectional imaging and represents a significant clinical challenge. Although most patients have a surgically curable lesion at the time of diagnosis, the variability in the biologic behavior of the different histologic subtypes and tumor grade of RCC, together with the increasing array of management options, creates uncertainty for the optimal clinical approach to individual patients. State-of-the-art magnetic resonance imaging (MRI) provides a comprehensive assessment of renal lesions that includes multiple forms of tissue contrast as well as functional parameters, which in turn provides information that helps to address this dilemma. In this article, we review this evolving and increasingly comprehensive role of MRI in the detection, characterization, perioperative evaluation, and assessment of the treatment response of renal neoplasms. We emphasize the ability of the imaging "phenotype" of renal masses on MRI to help predict the histologic subtype, grade, and clinical behavior of RCC.

Radiogenomics of clear cell renal cell carcinoma: associations between CT imaging features and mutations

PURPOSE

To investigate associations between computed tomographic (CT) features of clear cell renal cell carcinoma (RCC) and mutations in VHL, PBRM1, SETD2, KDM5C, or BAP1 genes.

MATERIALS AND METHODS

The institutional review board approved this retrospective, hypothesis-generating study of 233 patients with clear cell RCC and waived the informed consent requirement. The study was HIPAA compliant. Three radiologists independently reviewed pretreatment CT images of all clear cell RCCs without knowledge of their genomic profile. One radiologist measured largest diameter and enhancement parameters of each clear cell RCC. Associations between CT features and mutations in VHL, PBRM1, SETD2, KDM5C, and BAP1 genes were tested by using the Fisher exact test. Associations between mutations and size and enhancement were assessed by using the independent t test. Interreader agreement was calculated by using the Fleiss κ.

RESULTS

Mutation frequencies among clear cell RCCs were as follows: VHL, 53.2% (124 of 233); PBRM1, 28.8% (67 of 233); SETD2, 7.3% (17 of 233); KDM5C, 6.9% (16 of 233); and BAP1, 6.0% (14 of 233). Mutations of VHL were significantly associated with well-defined tumor margins (P = .013), nodular tumor enhancement (P = .021), and gross appearance of intratumoral vascularity (P = .018). Mutations of KDM5C and BAP1 were significantly associated with evidence of renal vein invasion (P = .022 and .046, respectively). The genotype of solid clear cell RCC differed significantly from the genotype of multicystic clear cell RCC. While mutations of SETD2, KDM5C, and BAP1 were absent in multicystic clear cell RCC, mutations of VHL (P = .016) and PBRM1 (P = .017) were significantly more common among solid clear cell RCC. Interreader agreement for CT feature assessments ranged from substantial to excellent (κ = 0.791-0.912).

CONCLUSION

This preliminary radiogenomics analysis of clear cell RCC revealed associations between CT features and underlying mutations that warrant further investigation and validation.

CT findings of synovial sarcomas of the kidney with pathological correlation

PURPOSE

To describe computed tomography (CT) findings of primary synovial sarcoma of the kidney with pathological correlation.

METHODS

CT findings of four cases of pathologically confirmed synovial sarcoma of the kidney were retrospectively viewed and correlated with pathologic features.

RESULTS

The four synovial sarcomas presented as soft tissue masses with multiple smooth wall cysts. Pathologically, entrapped and dilated renal tubules formed the smooth wall cysts lined by hobnail tubular epithelium.

CONCLUSION

Primary renal synovial sarcoma might manifest as a renal mass with multiple smooth wall cysts. The cysts are consistent with entrapped dilated renal tubular and are lined with hobnail tubular epithelium.

Cystic renal neoplasms and renal neoplasms associated with cystic renal diseases in adults: cross-sectional imaging findings

Cystic renal neoplasms in adults are a heterogeneous group of tumors with characteristic histogenesis, pathological findings, and variable biological profiles. They include disparate entities that are either biologically benign (lymphangioma, cystic nephroma, and mixed epithelial and stromal tumor) or malignant (cystic renal cell carcinoma, multilocular cystic renal cell carcinoma, and primary renal synovial sarcoma). Renal cystic diseases are characterized by cystic changes of the kidneys due to hereditary, developmental, or acquired etiology. Cystic renal diseases such as acquired cystic kidney disease, von Hippel-Lindau disease, and tuberous sclerosis are associated with the development of a wide spectrum of benign and malignant renal neoplasms. Most cystic renal tumors and cystic disease-associated renal neoplasms show characteristic cross-sectional imaging findings that permit accurate diagnosis. In addition, cross-sectional imaging is pivotal in the follow-up and surveillance of adult cystic tumors of the kidney.