ACR Appropriateness Criteria Renal Cell Carcinoma Staging

MR Virtual Biopsy of Solid Renal Masses: An Algorithmic Approach

Between 1983 and 2002, the incidence of solid renal tumors increased from 7.1 to 10.8 cases per 100,000. This is in large part due to the increase in the volume of ultrasound and cross-sectional imaging, although a majority of solid renal tumors are still found incidentally. Ultrasound and computed tomography (CT) have been the mainstay of renal mass screening and diagnosis but recent advances in magnetic resonance (MR) technology have made this the optimal choice when diagnosing and staging renal tumors. Our purpose in writing this review is to survey the modern MR imaging approach to benign and malignant solid renal tumors, consolidate the various imaging findings into an easy-to-read reference, and provide an imaging-based, algorithmic approach to renal mass characterization for clinicians. MR is at the forefront of renal mass characterization, surpassing ultrasound and CT in its ability to describe multiple tissue parameters and predict tumor biology. Cutting-edge MR protocols and the integration of diagnostic algorithms can improve patient outcomes, allowing the imager to narrow the differential and better guide oncologic and surgical management.

CT of the urinary tract revisited

Computed tomography (CT) of the abdomen is usually appropriate for the initial imaging of many urinary tract diseases, due to its wide availability, fast scanning and acquisition of thin slices and isotropic data, that allow the creation of multiplanar reformatted and three-dimensional reconstructed images of excellent anatomic details. Non-enhanced CT remains the standard imaging modality for assessing renal colic. The technique allows the detection of nearly all types of urinary calculi and the estimation of stone burden. CT is the primary diagnostic tool for the characterization of an indeterminate renal mass, including both cystic and solid tumors. It is also the modality of choice for staging a primary renal tumor. Urolithiasis and urinary tract malignancies represent the main urogenic causes of hematuria. CT urography (CTU) improves the visualization of both the upper and lower urinary tract and is recommended for the investigation of gross hematuria and microscopic hematuria, in patients with predisposing factors for urologic malignancies. CTU is highly accurate in the detection and staging of upper tract urothelial malignancies. CT represents the most commonly used technique for the detection and staging of bladder carcinoma and the diagnostic efficacy of CT staging improves with more advanced disease. Nevertheless, it has limited accuracy in differentiating non-muscle invasive bladder carcinoma from muscle-invasive bladder carcinoma. In this review, clinical indications and the optimal imaging technique for CT of the urinary tract is reviewed. The CT features of common urologic diseases, including ureterolithiasis, renal tumors and urothelial carcinomas are discussed.

Imaging Recommendations for Diagnosis, Staging, and Management of Renal Tumors

Renal cell carcinomas accounts for 2% of all the cancers globally. Most of the renal tumors are detected incidentally. Ultrasound remains the main screening modality to evaluate the renal masses. A multi -phase contrast enhanced computer tomography is must for characterizing the renal lesions. Imaging plays an important role in staging, treatment planning and follow up of renal cancers. In this review , we discuss the imaging guidelines for the management of renal tumors.

Using Peritumor and Intratumor Vascularity on Preoperative Imaging to Predict Fuhrman Grade Histology of Renal Tumors

Objective To investigate if peri-tumor and/or intra-tumor vasculature is associated with high grade tumor histology for renal cell carcinoma. Methods A retrospective review at a tertiary care facility was performed of patients who underwent radical nephrectomy or partial nephrectomy for a renal tumor between January 2015 to December 2020. Data of tumor characteristics was collected from final pathology reports. A single radiologist specializing in genitourinary imaging reviewed all pre-operative cross-sectional imaging for peri-tumor vessels and intra-tumor vessels. Single and multivariable logistic regression was utilized to identify variables associated with high grade tumor histology. Results The average tumor size on final pathology was 6.4 cm (Range 3.0-17.0 cm). Ninety-two patients (56.1%) had either an enlarged peri-tumor vessel (n=72), an intra-tumor vessel (n=3), or both a peri-tumor vessel and an intra-tumor vessel (n=17). Of the 92 patients with either a peri-tumor vessel or both a peri-tumor vessel and intra-tumor vessel, 60.9% of these patients had high Fuhrman grade histology on final pathology (60.9% vs 39.1%, p<0.001). Pathologic stage T1a tumors with an enlarged peri-tumor vessel on pre-operative imaging were associated with high Fuhrman grade histology (58.3% vs 41.7%, p=0.015). Across all stages, the presence of an enlarged peritumor vessel was significantly associated with high Fuhrman grade (OR: 2.37, 95% CI 1.17 - 4.9, p = 0.01). Conclusion Findings suggest that vessels surrounding small renal tumors and large renal tumors is associated with high tumor grade (FG > 3). Further research is needed to support the association of peri-tumor vessels with high tumor grade.

Metabolic tumour volume on 18F-FDG PET/CT predicts extended pathological T stages in patients with renal cell carcinoma at staging

We evaluated the predictive value of ¹⁸F-fluorodeoxyglucose (FDG) uptake on positron emission tomography/CT (PET/CT) for extended pathological T (pT) stages (≥ pT3a) in Renal cell carcinoma (RCC) patients at staging. Thirty-eight RCC patients who underwent ¹⁸F-FDG PET/CT at staging, followed by radical nephrectomy between September 2016 and September 2018, were included in this prospective study. Patients were classified into two groups (limited pT stage: stage T1/2, n = 17; extended pT stage: T3/4, n = 21). Univariate and multivariate logistic regression analyses were performed to identify clinicopathological and metabolic variables to predict extended pT stages. ¹⁸F-FDG metabolic parameters were compared in relation to International Society of Urological Pathology (ISUP) grade and lymphovascular invasion (LVI). In univariate analysis, maximum standardised uptake value, metabolic tumour volume (MTV), and ISUP grade were significant. In multivariate analysis, MTV was the only significant factor of extended pT stages. With a cut-off MTV of 21.2, an area under the curve was 0.944, which was higher than 0.824 for clinical T stages (p = 0.037). In addition, high MTV, but not tumour size, was significantly correlated with aggressive pathologic features (ISUP grade and LVI). High glycolytic tumour volume on ¹⁸F-FDG PET/CT in RCC patients at staging is predictive of extended pT stages which could aid decision-making regarding the best type of surgery.

Imaging considerations for thermal and radiotherapy ablation of primary and metastatic renal cell carcinoma

Ablative (percutaneous and stereotactic) thermal and radiotherapy procedures for management of both primary and metastatic renal cell carcinoma are increasing in popularity in clinical practice. Data suggest comparable efficacy with lower cost and morbidity compared to nephrectomy. Ablative therapies may be used alone or in conjunction with surgery or chemotherapy for treatment of primary tumor and metastatic disease. Imaging plays a crucial role in pre-treatment selection and planning of ablation, intra-procedural guidance, evaluation for complications, short- and long-term post-procedural surveillance of disease, and treatment response. Treatment response and disease recurrence may differ considerably after ablation, particularly for stereotactic radiotherapy, when compared to conventional surgical and chemotherapies. This article reviews the current and emerging role of imaging for ablative therapy of renal cell carcinoma.

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.

The role of imaging in the management of renal masses

The wide availability of cross-sectional imaging is responsible for the increased detection of small, usually asymptomatic renal masses. More than 50 % of renal cell carcinomas (RCCs) represent incidental findings on noninvasive imaging. Multimodality imaging, including conventional US, contrast-enhanced US (CEUS), CT and multiparametric MRI (mpMRI) is pivotal in diagnosing and characterizing a renal mass, but also provides information regarding its prognosis, therapeutic management, and follow-up. In this review, imaging data for renal masses that urologists need for accurate treatment planning will be discussed. The role of US, CEUS, CT and mpMRI in the detection and characterization of renal masses, RCC staging and follow-up of surgically treated or untreated localized RCC will be presented. The role of percutaneous image-guided ablation in the management of RCC will be also reviewed.

Controversies in the diagnosis of renal cell carcinoma with tumor thrombus

Diagnosis and treatment of renal cell carcinoma with venous tumor thrombosis remains a challenge today, requiring multidisciplinary teams, mainly in tumor thrombus levels III-IV. Our objective is to present the various diagnostic techniques used and its controversies. A review of the most relevant related articles between January 2000 and August 2020 has been carried out in PubMed, EMBASE and Scielo. Continuous technological development has allowed progress in its detection, in the approximation of the histological subtype, and in the determination of tumor thrombus level. Regardless of the imaging technique used for its diagnosis (CT, MRI, TEE, ultrasound with contrast), the time elapsed until treatment is vitally important to reduce the risk of complications, some of them fatal, such as pulmonary thromboembolism.

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

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

Renal cell carcinoma with unusual visceral and cutaneous metastasis

Renal cell carcinoma is a common urogenital malignancy. It often metastasizes to the lungs, liver, bone, adrenal glands, and brain in the advanced stage. However, the involvement of the skin and subcutaneous region of the head and neck is rare. We report a case of a middle-aged man presented with extensive metastases to post radical nephrectomy. The nose and lower lip metastasis with submental lymph nodal mass is not previously reported. He also had metachronous prostatic adenocarcinoma. The case highlights the excellent capability of molecular imaging using fluorodeoxyglucose-positron-emission tomography/computed tomography to pick up all metastatic lesions and find metachronous prostate malignancy.

Von Hippel-Lindau syndrome and renal tumours: radiological diagnostic and treatment options. A case report and literature review

Background

Von Hippel-Lindau disease (VHL) is a rare autosomal dominant syndrome diagnosed for 1 out of 36000-45000 newborns and 90% of the patients have a clinical manifestation before 65 years of age. Affected individuals have an increased risk of developing tumours in several organs or their systems. The most common tumours are retinal or central nervous system hemangioblastomas (60-80%) and VHL-associated renal lesions. Contrast-enhanced computer tomography (CECT) is the gold standard for the diagnosis and characterization of renal tumours. The best treatment option for VHL syndrome-caused renal tumours are nephron-sparing treatment techniques (cryotherapy, radiofrequency, or microwave ablation), which require imaging control. All these innovative treatment techniques are extremely important for VHL patients, because they increase the quality of life by staving off renal dialysis and preventing distant metastases.

Case report

Our case report presents a 16-year-old female with multiple renal cysts observed on ultrasound examination and clinically and molecularly diagnosed with Von Hippel-Lindau syndrome (deletion of the entire VHL gene). After that, for past 11 years multiple renal tumours were removed by cryoablation and patient monitoring on contrast-enhanced magnetic resonance (MRI) and CECT control scans was conducted.

Conclusions

Active multidisciplinary patient follow-up, routine radiological examinations, and correct treatment tactics allow controlling the  progression of renal cell carcinoma and other tumours associated with VHL syndrome, maintaining a normal organ function for a long time, and preventing distant metastases and fatal disease outcomes.

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Imaging for Metastatic Renal Cell Carcinoma

Patients with renal cell carcinoma may develop metastases after radical nephrectomy, and therefore monitoring with imaging for recurrent or metastatic disease is critical. Imaging varies with specific suspected site of disease. Computed tomography/MRI of the abdomen and pelvis are mainstay modalities. Osseous and central nervous system imaging is reserved for symptomatic patients. Radiologic reporting is evolving to reflect effects of systemic therapy on lesion morphology. Nuclear medicine studies compliment routine imaging as newer agents are evaluated for more accurate tumor staging. Imaging research aims to fill gaps in treatment selection and monitoring of treatment response in metastatic renal cell carcinoma.

Renal pelvic and ureteral wall thickening in renal cell carcinoma: prevalence, cause, and clinical significance

PURPOSE

This study was performed to characterize renal pelvic and ureteral wall thickening (PUWT) in renal cell carcinoma (RCC) patients, including prevalence, cause, and detailed radiological findings based on contrast-enhanced CT, and to correlate these features with corresponding pathological findings.

MATERIALS AND METHODS

152 patients pathologically diagnosed with RCC by surgery were included. Two radiologists retrospectively evaluated the presence of PUWT and the radiological characteristics based on CT. Relationships among clinical characteristics, CT findings, and PUWT were evaluated. Pathological findings of PUWT were also investigated.

RESULTS

The prevalence of RCC-related PUWT was 10% (N = 15). PUWT was frequently observed in cases with advanced TNM stage. Tumor thrombus, sinus extent, and peritumoral neovascularity were significantly more frequent in cases with PUWT. PUWT was observed at the pelvis or from the pelvis to the upper ureter. Fourteen of 15 cases in which the pelvic/ureteral wall was pathologically investigated did not show any pathological abnormalities.

CONCLUSION

The prevalence of PUWT was 10% and most cases were thought to be caused by temporary vascular dilatation in the pelvis and ureter, which is a secondary condition caused by hypervascular RCC, and not a direct result of tumor invasion.

Thoracic Manifestations of Genitourinary Neoplasms and Treatment-related Complications

Genitourinary (GU) malignancies are a diverse group of common and uncommon neoplasms that may be associated with significant mortality. Metastases from GU neoplasms are frequently encountered in the chest, and virtually all thoracic structures can be involved. Although the most common imaging manifestations include hematogenous dissemination manifesting with peripheral predominant bilateral pulmonary nodules and lymphatic metastases manifesting with mediastinal and hilar lymphadenopathy, some GU malignancies exhibit unique features. We review the general patterns, pathways, and thoracic imaging features of renal, adrenal, urothelial, prostatic, and testicular metastatic neoplasms, as well as provide a discussion of treatment-related complications that might manifest in the chest. Detailed reporting of these patterns will allow the imager to assist the referring clinicians and surgeons in accurate determination of the stage, prognosis, and treatment options available for the patient. Awareness of specific treatment-related complications further allows the imager to enhance patient safety through accurate and timely reporting of potentially life-threatening consequences of therapies.

Magnetic resonance imaging (MRI) of the renal sinus

This article presents methods to improve MR imaging approach of disorders of the renal sinus which are relatively uncommon and can be technically challenging. Multi-planar Single-shot T2-weighted (T2W) Fast Spin-Echo sequences are recommended to optimally assess anatomic relations of disease. Multi-planar 3D-T1W Gradient Recalled Echo imaging before and after Gadolinium administration depicts the presence and type of enhancement and relation to arterial, venous, and collecting system structures. To improve urographic phase MRI, concentrated Gadolinium in the collecting systems should be diluted. Diffusion-Weighted Imaging (DWI) should be performed before Gadolinium administration to minimize T2* effects. Renal sinus cysts are common but can occasionally be confused for dilated collecting system or calyceal diverticula, with the latter communicating with the collecting system and filling on urographic phase imaging. Vascular lesions (e.g., aneurysm, fistulas) may mimic cystic (or solid) lesions on non-enhanced MRI but can be suspected by noting similar signal intensity to the blood pool and diagnosis can be confirmed with MR angiogram/venogram. Multilocular cystic nephroma commonly extends to the renal sinus, however, to date are indistinguishable from cystic renal cell carcinoma (RCC). Solid hilar tumors are most commonly RCC and urothelial cell carcinoma (UCC). Hilar RCC are heterogeneous, hypervascular with epicenter in the renal cortex compared to UCC which are centered in the collecting system, homogeneously hypovascular, and show profound restricted diffusion. Diagnosis of renal sinus invasion in RCC is critically important as it is the most common imaging cause of pre-operative under-staging of disease. Fat is a normal component of the renal sinus; however, amount of sinus fat correlates with cardiovascular disease and is also seen in lipomatosis. Fat-containing hilar lesions include lipomas, angiomyolipomas, and less commonly other tumors which engulf sinus fat. Mesenchymal hilar tumors are rare. MR imaging diagnosis is generally not possible, although anatomic relations should be described to guide diagnosis by percutaneous biopsy or surgery.

Society of Abdominal Radiology disease-focused panel on renal cell carcinoma: update on past, current, and future goals

The disease-focused panel (DFP) program was created by the Society of Abdominal Radiology (SAR) as a mechanism to "improve patient care, education, and research" in a "particular disease or a particular aspect of a disease". The DFP on renal cell carcinoma (RCC) was proposed in 2014 and has been functional for 4 years. Although nominally focused on RCC, the scope of the DFP has included indeterminate renal masses because many cannot be assigned a specific diagnosis when detected. Since its founding, the DFP has been active in a variety of clinical, research, and educational projects to optimize the care of patients with known or suspected RCC. The DFP is utilizing multi-institutional and cross-disciplinary collaboration to differentiate benign from malignant disease, optimize the management of early stage RCC, and ultimately to differentiate indolent from aggressive cancers. Several additional projects have worked to develop a quantitative biomarker that predicts metastatic RCC response to anti-angiogenic therapy. While disease focus is the premise by which all DFPs are created, it is likely that in the future the RCC DFP will need to expand or create new panels that will focus on other specific aspects of RCC-a result that the program's founders envisioned. New knowledge creates a need for more focus.

Imaging of Solid Renal Masses

The increase in serendipitous detection of solid renal masses on imaging has not resulted in a reduction in mortality from renal cell carcinoma. Consequently, efforts for improved lesion characterization have been pursued and incorporated into management algorithms for distinguishing clinically significant tumors from those with favorable histology or benign conditions. Although diagnostic imaging strategies have evolved for optimized lesion detection, distinction between benign tumors and both indolent and aggressive malignant neoplasms remain an important diagnostic challenge. Recent advances in cross-sectional imaging have expanded the role of these tests in the noninvasive characterization of solid renal tumors.

Secondary Tumors of the Urinary System: An Imaging Conundrum

Imaging features of metastases to the urinary system may closely mimic primary urinary tract tumors, and differential diagnosis by imaging alone may be problematic or even impossible in some cases. The main purpose of this article was to familiarize radiologists with imaging findings of metastasis to the urinary system on cross-sectional imaging, with an emphasis on abdominal and pelvic computed tomography and magnetic resonance imaging. In addition, we review the clinical importance and implications of metastases to the urinary tract and provide information on diagnostic work-ups.

Imaging and Management of Intrathoracic Renal Cell Carcinoma Metastases

OBJECTIVE

Renal cell carcinoma (RCC) has a propensity to metastasize to the chest, with the lungs being the most common distant metastatic site. The histologic subtype of RCC has implications for prognosis.

CONCLUSION

Significant advances have been made in the management of metastatic RCC, both in systemic and locoregional therapies. The aim of this article is to review appearances of intrathoracic metastases from RCC and to discuss treatment considerations.

Advances in medical imaging for the diagnosis and management of common genitourinary cancers

Medical imaging of the 3 most common genitourinary (GU) cancers-prostate adenocarcinoma, renal cell carcinoma, and urothelial carcinoma of the bladder-has evolved significantly during the last decades. The most commonly used imaging modalities for the diagnosis, staging, and follow-up of GU cancers are computed tomography, magnetic resonance imaging (MRI), and positron emission tomography (PET). Multiplanar multidetector computed tomography and multiparametric MRI with diffusion-weighted imaging are the main imaging modalities for renal cell carcinoma and urothelial carcinoma, and although multiparametric MRI is rapidly becoming the main imaging tool in the evaluation of prostate adenocarcinoma, biopsy is still required for diagnosis. Functional and molecular imaging using 18-fluorodeoxyglucose-PET and sodium fluoride-PET are essential for the diagnosis, and especially follow-up, of metastatic GU tumors. This review provides an overview of the latest advances in the imaging of these 3 major GU cancers.

Imaging of Solid Renal Masses

Detection of solid renal masses has increased, although it has not resulted in significant mortality reduction from renal cell carcinoma. Efforts for improved lesion characterization have been pursued and incorporated in management algorithms, in order to distinguish clinically significant tumors from favorable or benign conditions. Concurrently, imaging methods have produced evidence supporting their role as useful tools not only in lesion detection but also characterization. In addition, newer modalities, such as contrast-enhanced ultrasonography, and advanced applications of MR imaging, are being investigated. This article reviews the current role of different imaging methods in the characterization of solid renal masses.