Malignant tumours of the kidney: imaging strategy

A rare case of renal tumor in children: Clear cell sarcoma with an unusual presentation

Clear cell sarcoma of the kidney is the most frequently misdiagnosed renal tumor in children. We report the case of a 6-year-old boy with clear cell sarcoma of the kidney with an unusual presentation, including a primary tumor of the left kidney with metastasis in the homolateral psoas muscle. The renal tumor was revealed by abdominal mass without hematuria. In a review of the literature. Clear cell sarcoma of the kidney is most commonly associated with bone and lung metastases. Muscular metastasis at initial diagnosis has not previously been reported. This case represents an unusual metastatic pattern of clear cell sarcoma of the kidney. This also illustrates clear cell sarcoma of the kidney's ability to metastasize to other sites including the muscular. These tumors present a diagnostic challenge for the radiologist who should be aware of this entity to differentiate it from other renal tumors which are more frequent at this age. We aim to report the clinical, radiological features, and pathological presentation of this entity.

Diagnostic value of pseudocapsule ring hyperenhancement in contrast-enhanced ultrasound in renal focal lesions

OBJECT

To investigate the diagnostic value of pseudocapsule ring hyperenhancement in contrast-enhanced ultrasound (CEUS) of focal renal lesions.

METHOD

Ninety eligible patients admitted were selected as the study subjects. The incidence rate of annular hyperenhancement in different benign and malignant focal lesions during angiography and the shape of annular enhancement were counted. The correlation between the occurrence of benign and malignant renal tumors and annular hyperenhancement and unenhanced areas was also analyzed.

RESULTS

Capsule enhancement was observed in 56 cases, including 50 cases of malignant tumors (89.3%, 50/56) and 6 cases of benign tumors (10.7%, 6/56). Pearson correlation analysis showed that renal malignancy was positively associated with the occurrence of pseudocapsule ring hyperenhancement (γ = 0.489, P < 0.001). Benign and malignant renal tumors were positively correlated with the occurrence of non-enhancing areas (γ = 0.215, P = 0.042). The thickness and peak intensity of pseudocapsule ring enhancement in renal malignant tumors were significantly higher than those in benign tumors (all P < 0.001), while the time to peak was significantly lower than that in benign tumors (P < 0.001). The results of receiver operating characteristic (ROC) curve showed that the ring enhancement thickness, time to peak, and area under ROC curve of peak intensity of tumor reached more than 0.9.

CONCLUSION

In CEUS, the pseudocapsule of focal renal lesions is a characteristic feature of renal malignant tumors, which can be used as a differential basis for benign and malignant tumors to improve the accuracy of benign and malignant renal tumors.

A comparison between ultrasonography and single-phase computed tomography for preoperative assessment of solid abdominal tumors in children

OBJECTIVE

This study aimed to estimate the performance of single-phase-enhanced computed tomography and ultrasonography examinations in the preoperative evaluation of solid abdominal tumors and their relationship with relevant adjacent structures in children.

METHODS

This retrospective study included 50 pediatric patients with malignant solid abdominal tumors treated with surgical resection between 2009-2017. Preoperative computed tomography and ultrasonography were compared to operative findings (gold standard) in the diagnosis of invasion or encasement of adjacent structures. Accuracy, sensitivity, specificity, and positive and negative predictive values were evaluated.

RESULTS

Renal (20.4%) and neuroblastic (19.4%) tumors were the most common. Complete surgical resection with negative margins was achieved in 44 (88%) patients. The comparison between single-phase-enhanced computed tomography and ultrasonography findings showed the following results: sensitivity = 90.3% vs 86.6%, specificity = 86.8% vs 94.6%, negative predictive value = 95.3% vs 94.4%, positive predictive value = 75.3% vs 86.9%, and accuracy = 87.9% vs 92.2%. The correlation (kappa index) between computed tomography and ultrasonography examinations was 0.72 (p < 0.001). In 14% (7/50) of the patients, the invasion of adjacent structures was diagnosed by ultrasonography but not by computed tomography (1 patient had 2 invaded structures).

CONCLUSION

Ultrasonography can be considered a complementary method to single-phase-enhanced computed tomography in the preoperative evaluation of children with an abdominal tumor. The present study showed that ultrasonography and single-phase-enhanced computed tomography each possess a high accuracy in the preoperative planning of resection of solid abdominal tumors in children. Thus, it seems that the combination of both imaging methods would be enough for the evaluation of most abdominal tumors in the pediatric population.

Wilms tumors and their precursors: Radiological diagnosis versus histology

The radiological distinction of Wilms tumor (WT) nodules from nephrogenic rests (NR) in patients with multifocal unilateral WT or bilateral disease is challenging. The study aims to compare the radiology assessment of kidney nodules with their final histology in 48 patients. The final histology of 118 nodules corresponded to the initial radiological diagnosis while 40 (25%) nodules were misdiagnosed, 20 being initially diagnosed WT on imaging were proved to be NR at histology. The size of nodules at diagnosis might help to distinguish WT from NR before surgery. Homogeneity did not seem to be a key feature.

Position paper: Rationale for the treatment of children with CCSK in the UMBRELLA SIOP-RTSG 2016 protocol

The International Society of Paediatric Oncology-Renal Tumour Study Group (SIOP-RTSG) has developed a new protocol for the diagnosis, treatment, and follow-up monitoring of childhood renal tumours - the UMBRELLA SIOP-RTSG 2016 protocol (the UMBRELLA protocol). This protocol has been designed to continue international collaboration in the treatment of childhood renal tumours and will be implemented in over 50 different countries. Clear cell sarcoma of the kidney, which is a rare paediatric renal tumour that most commonly occurs in children between 2 and 4 years of age, is specifically addressed in the UMBRELLA protocol.

Renal Tumors of Childhood: Radiologic-Pathologic Correlation Part 1. The 1st Decade: From the Radiologic Pathology Archives

Wilms tumor is the second most common pediatric solid tumor and by far the most common renal tumor of infants and young children. As most tumors are large at presentation and are treated with nephrectomy, the role of imaging is primarily in preoperative planning and evaluation for metastatic disease. However, with treatment protocols increasingly involving use of preoperative (neoadjuvant) chemotherapy (the standard in Europe) and consideration of nephron-sparing surgery, the role of imaging is evolving to include providing initial disease staging information and a presumptive diagnosis to guide therapy. Differential diagnostic considerations include lesions that are clinically benign and others that require more intensive therapy than is used to treat Wilms tumor. In part 1 of this article, the unique histologic spectrum of renal neoplasms of infants and young children is reviewed with emphasis on radiologic-pathologic correlation. Part 2 will focus on renal tumors of older children and adolescents.

[Clear cell sarcoma of kidney in children]

Clear cell sarcoma of the kidney (CCSK) is a rare tumor that is diagnosed most often in children between 2- and 4-years-old of age. Usually, patients with CCSK are treated in international study for intrarenal tumors, preferentially Wilms tumor, according to bad histopronostic group. The purpose of this paper is to review the most important features in 2015 about epidemiology, radiology, anatomopathology and genetic of CCSK, and above all a synthesis about successive treatment strategies with their results. Second most common pediatric renal tumor in children less than 5-years-old, its prognosis has improved dramatically in recent years with the use of anthracyclines.

A multi-Gaussian model for apparent diffusion coefficient histogram analysis of Wilms' tumour subtype and response to chemotherapy

Wilms' tumours (WTs) are large heterogeneous tumours, which typically consist of a mixture of histological cell types, together with regions of chemotherapy-induced regressive change and necrosis. The predominant cell type in a WT is assessed histologically following nephrectomy, and used to assess the tumour subtype and potential risk. The purpose of this study was to develop a mathematical model to identify subregions within WTs with distinct cellular environments in vivo, determined using apparent diffusion coefficient (ADC) values from diffusion-weighted imaging (DWI). We recorded the WT subtype from the histopathology of 32 tumours resected in patients who received DWI prior to surgery after pre-operative chemotherapy had been administered. In 23 of these tumours, DWI data were also available prior to chemotherapy. Histograms of ADC values were analysed using a multi-Gaussian model fitting procedure, which identified 'subpopulations' with distinct cellular environments within the tumour volume. The mean and lower quartile ADC values of the predominant viable tissue subpopulation (ADC(1MEAN), ADC(1LQ)), together with the same parameters from the entire tumour volume (ADC(0MEAN), ADC(0LQ)), were tested as predictors of WT subtype. ADC(1LQ) from the multi-Gaussian model was the most effective parameter for the stratification of WT subtype, with significantly lower values observed in high-risk blastemal-type WTs compared with intermediate-risk stromal, regressive and mixed-type WTs (p < 0.05). No significant difference in ADC(1LQ) was found between blastemal-type and intermediate-risk epithelial-type WTs. The predominant viable tissue subpopulation in every stromal-type WT underwent a positive shift in ADC(1MEAN) after chemotherapy. Our results suggest that our multi-Gaussian model is a useful tool for differentiating distinct cellular regions within WTs, which helps to identify the predominant histological cell type in the tumour in vivo. This shows potential for improving the risk-based stratification of patients at an early stage, and for guiding biopsies to target the most malignant part of the tumour.

Magnetic resonance imaging versus histopathology in Wilms tumor and nephroblastomatosis: 3 examples of noncorrelation

Magnetic resonance imaging (MRI) has become the principal tool for Wilms tumor (WT) assessment and follow-up. MRI and histopathologic findings were not congruent in 2 of the q30 scanned patients with renal masses (2008 to 2011). Three lesions thought to be WT on MRI were found to be a sclerotic nephrogenic rest (1), cystic renal dysplasia (1), and focal chronic pyelonephritis (1). The "typical" features suggesting nephroblastomatosis and WT on MRI are unreliable and such lesions require biopsy for histopathologic diagnosis, especially when nephron-sparing surgery is necessary to preserve renal function.

WARM N COLD: malignant and benign renal tumors in children

Although Wilms tumor is the most common renal malignancy in children, the differential diagnosis is extensive and includes both malignant and benign disorders. We present a simple mnemonic-WARM N COLD, to aid in remembering these diverse tumors. Imaging clues including age of the patient, associated disease or syndrome as well as salient imaging characteristics such as bilaterality, and type or presence of metastasis are also presented and can help differentiate between these renal tumors of childhood.

Understanding the principles in management of Wilms' tumour: can imaging assist in patient selection?

The management of Wilms' tumour has evolved through thorough systematic research, predominantly lead by two groups: the Wilms' Tumour Study Committee of the International Society of Paediatric Oncology (SIOP) and National Wilms' Tumor Study Group (NWTSG) of North America. These two groups differ in their approach: SIOP advocates initial chemotherapy of 4-6 weeks followed by surgery, whereas the NWTSG advocates upfront surgery, with certain exceptions. This review briefly discusses the principles, and pros and cons of each approach. Both the treatment approaches have equivalent outcomes (in the form of event-free survival and overall survival), when compared stage-wise. With this knowledge, modern imaging can be used for individualizing treatment in anticipation of minimizing complications. The review identifies critical imaging features and discusses the reliability of imaging based on current reports in the literature.

Usefulness of the computed tomography and magnetic resonance in evaluation of progress of treatment of the neoplasmatic diseases in children

Background:

Neoplastmatic diseases constitute about 1% diseases in children in Poland, what makes about 1200 new incidents during one year. Fast diagnosis in those illnesses is crucial in treatment results. The point of this work was to value usefulness of CT and MRI in diagnostics of neoplasmatic diseases in children.

Material/Methods:

The retrospective study involved 121 children examined in CT and MRI because of suspicion or during treatment of neoplasmatic disease. Together 184 CT and 119 MRI examination were performed. Eventually in 106 children neoplasmatic disease was diagnosed. In 16 cases neoplasm was excluded.

Results:

In the analyzed group of patients acute lymphoblastic and non lymphoblastic leukemia was diagnosed in 68 children (55.7%); among them mycosis was identified after radiological examinations in 7 cases (10.3%). 8 children (6.6%) with non Hodgkin lymphoma and 11 (9%) with Hodgkin lymphoma were examined. Nephroblastoma was found after MRI and CT in 6 cases (4.9%). Presence of tumors, that were classified histopatologically as PNET, was confirmed in 4 children. In 15 cases after MRI and CT neoplasmatic disease was excluded.

Conclusions:

Depending on the kind of sickness MRI and CT may fulfill basic or subsidiary role in diagnostic and estimating the progress of treatment in neoplasmatic diseases among children.

CT and MRI appearances and radiologic staging of pediatric renal cell carcinoma

BACKGROUND

Renal cell carcinoma (RCC) is an uncommon but noteworthy primary pediatric renal malignancy. There is a paucity of published data regarding the CT/MRI appearances and accuracy of pretreatment radiologic staging of this form of cancer in children.

OBJECTIVE

To review the various CT/MRI appearances of pediatric RCC and assess the accuracy of pretreatment radiologic staging using these imaging modalities.

MATERIALS AND METHODS

Institutional Departments of Pathology and Radiology records were searched from 1995 through 2010 for children (younger than 18 years of age) with RCC. Available pretreatment contrast-enhanced abdominopelvic CT and MRI examinations were reviewed by two radiologists. Pertinent imaging findings were documented by consensus, and correlation was made between radiologic and surgicopathological TNM staging.

RESULTS

Pretreatment imaging studies from 10 RCCs in nine children (four girls and five boys; mean age 12.9 years) were reviewed. The mean size of the primary tumor was 6.2 cm (range, 1.5-12.6 cm). Ninety percent of RCCs demonstrated heterogeneous postcontrast enhancement. Fifty percent of masses had associated hemorrhage, while 40% contained internal calcification. Regarding TNM staging, N staging was correct for 10 of 10 tumors, while M staging was correct for 10 of 10 tumors. Imaging correctly staged only 4 of 10 tumors with respect to T stage. Radiologic and surgicopathological overall staging were concordant for 8 of 10 tumors.

CONCLUSION

Pediatric RCCs typically present as large, heterogeneous masses, and they commonly hemorrhage and contain internal calcification. Radiologic and surgicopathological overall TNM staging are frequently concordant, although radiologic T staging is often incorrect.

Computerized tomography in pediatric oncology

Computerized tomography (CT) is an extremely powerful imaging modality, which provides extremely valuable information for the diagnosis, staging, and management of pediatric solid tumors. In recent years, the concern of potential risks associated with ionizing radiation from diagnostic imaging - especially from CT - has greatly increased. In children with cancer the radiation burden from CT studies can easily accumulate because of repeated studies for disease staging, assessment of response to therapy, and follow up. The purpose of this article is to review the role of CT and its imaging key points for diagnosis, staging and planning surgical excision of common extracranial pediatric tumors, according to protocol specific imaging guidelines. The issue of the radiation burden from CT in children with cancer, and criteria of good practice to reduce it, will also be discussed.

Increased survival of children with solid tumours: how did we get there and how to keep the success going?

Survival after childhood cancer has dramatically increased in the last 3 to 4 decades. Among extracranial tumours, Wilms tumours and other less common kidney tumours have the best results, but treatment of neuroblastoma, often disseminated at diagnosis, is still extremely challenging. How did survival of solid tumours in childhood increase from around 30% in the 1970s to 70-90% today? This is the result of a multidisciplinary effort and access to improved diagnostic techniques and treatment modalities. This article focuses on the role of imaging in this positive evolution and particularly, how imaging will contribute to keep the survival curves improving. Radiologists and other imaging experts retain a key position before diagnosis and during and after treatment. Investigations before diagnosis are key to further investigations and referral with no delay. The first investigations will most often involve radiologists through radiography or ultrasonography, according to tumour site. The description of these first observations and particularly the conclusion and its wording are crucial to the subsequent events leading to diagnosis. In imaging at diagnosis, the aim is to obtain a precise description of the primary tumour and its local spread as soon as possible. The choice of technique depends on local conditions but may include ultrasonography, computed tomography (CT)/magnetic resonance imaging (MRI) scanning, scintigraphies (bone, meta-iodobenzylguanidine (MIBG), octreotide), or fluorodeoxyglucose (FDG)-positron emission tomography (PET), combined with low dose CT or MRI scanning. CT scan and chest radiography are recommended for investigating the presence of lung metastases. There is no infiltrate too small to be a metastasis. Overall there is no specific imaging criterion. The pathologists hold this diagnostic key. Tumour response is evaluated during and after preoperative chemotherapy using techniques and measurements comparable with those used at diagnosis. Following evaluation of tumour response, additional investigations may be needed to define the resectability of the tumour, combining different imaging techniques, e.g. CT scanning and/or MRI angiographies, ultrasound with Doppler. After tumour resection and particularly in the case of non-radical resection, imaging of the tumour residue is required as baseline for further surveillance and eventually planning of irradiation fields. How do we secure further improvement in treatment results for childhood cancer? Multidisciplinary teams, optimal logistics and continuous education are the best tools with focus on reduction in delay to diagnosis and improvement in the multidisciplinary forum allowing optimal therapeutic decisions.

The contribution of chest CT-scan at diagnosis in children with unilateral Wilms' tumour. Results of the SIOP 2001 study

BACKGROUND

The SIOP 2001 nephroblastoma study hypothesised that patients with 'CT-only' pulmonary nodules would have the same outcome as patients with localised disease of same stage and histology.

PATIENTS

Unilateral Wilms' tumour (WT) patients, who had chest CT scans at diagnosis showing any sized pulmonary nodules undetected on chest X-ray, between November 2001 and November 2009, were selected from the SIOP 2001 database.

RESULTS

Among 2532 WT patients, 103 unilateral nephroblastoma patients with CT-only lung lesions were found. Thirty-seven patients received preoperative treatment according to the localised-disease protocol, and 66 according to the metastatic-disease protocol. The 3-year event-free survival (EFS) was 70% (95% CI: 55-89%) and 77% (95% CI: 66-89%), respectively. Corresponding 3-year overall survival (OS) was 89% (95% CI: 77-100%) and 85% (95% CI: 75-96%), respectively (p-value not significant). EFS and OS of all 2071 patients with true localised disease were 87% (95% CI: 86-89%) and 96% (95% CI: 94-97%), respectively. Patients with metastatic disease (n = 358) had 3-year EFS and OS estimates of 68% (95% CI: 63-74%) and 77% (95% CI: 72-82%), respectively.

CONCLUSIONS

EFS and OS of patients with CT-only lung lesions were inferior to that of true localised-disease patients and superior to that of patients with metastatic disease. However, no significant difference was found in EFS and OS between CT-only patients treated for localised or metastatic disease. The clinician's preference to treat patients with CT-only pulmonary nodules as metastatic disease is not evidence-based. Chest CT at diagnosis does not improve outcome but presents paediatric oncologists with a difficult dilemma.

Using Sonography to Characterize Renal Cell Carcinoma: Case Study of a Large Renal Mass

Renal cell carcinoma (RCC) is both the most common—and deadly—renal tumor in the adult population. It is categorized into various subtypes, with clear cell RCC being the most common of those. Sonography, in addition to other imaging modalities, is important in discovering, describing, staging, and ultimately predicting the outcome of RCC. This article presents a case study of a woman in her 60s diagnosed with late clear cell RCC with multiple metastases. It also addresses recent literature regarding outcomes for this disease.