Figure - available from: Pediatric Radiology
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A 10-year-old girl with desmoplastic small round cell tumor (patient 27 in Table 1). A coronal T2-weighted image (a) shows a mass in the right kidney containing a T2 hyperintense cystic portion and a hypointense thin rim. An axial T1-weighted pre-contrast image (b) shows the mass is mildly hypointense relative to renal parenchyma. An axial contrast-enhanced T1-weighted image (c) shows that the mass is hypointense relative to enhanced parenchyma with mildly enhancing septa and a solid portion. A diffusion-weighted image (d) and a corresponding apparent diffusion coefficient map (e) show that the solid component of the mass has restricted diffusion. An axial pre-contrast tomography image (f) shows extensive coarse calcification, which is typical for desmoplastic small round cell tumor
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Background
Compared to Wilms, non-Wilms renal tumors in children are less well understood due to their rare occurrence which limits precise definition of the typical imaging patterns.
Objective
This study aims to identify distinctive imaging findings, demographic characteristics and prognosis of pediatric non-Wilms renal tumors.
Materials and met...
Citations
... Based on previous case reports and small retrospective studies, congenital mesoblastic nephroma is typically described as homogeneous and isointense to normal renal parenchyma [4,7,12,14,33]. The cellular type seems to be more heterogeneous, making differentiation from malignant tumors more difficult [3,6,8,21,28,[33][34][35][36][37]. Therefore, identification of specific MRI characteristics of congenital mesoblastic nephroma at diagnosis, especially in young children, is important for the discrimination from Wilms tumors and more aggressive non-Wilms tumor [11,29,34,38]. ...
... Based on previous case reports and small retrospective studies, congenital mesoblastic nephroma is typically described as homogeneous and isointense to normal renal parenchyma [4,7,12,14,33]. The cellular type seems to be more heterogeneous, making differentiation from malignant tumors more difficult [3,6,8,21,28,[33][34][35][36][37]. Therefore, identification of specific MRI characteristics of congenital mesoblastic nephroma at diagnosis, especially in young children, is important for the discrimination from Wilms tumors and more aggressive non-Wilms tumor [11,29,34,38]. ...
... Above the age of 3 months, a combination of certain clinical, radiological, and biochemical criteria are usually used to decide if a diagnostic cutting needle biopsy is indicated [26,27]. In general, some studies have indicated the incidence of congenital mesoblastic nephroma is higher in males than females, whereas we only saw a slight predominance of male patients in our study (57.7%) [33,[45][46][47]. Metastases are described in approximately 2% of patients with the cellular type, which is in line with only one suspected metastatic case in this study [11,13,15,18,21,35,37]. ...
Background
Congenital mesoblastic nephroma is the most common solid renal tumor in neonates. Therefore, patients <3 months of age are advised to undergo upfront nephrectomy, whereas invasive procedures at diagnosis in patients ≥3 months of age are discouraged by the International Society of Pediatric Oncology-Renal Tumor Study Group (SIOP-RTSG). Nevertheless, discriminating congenital mesoblastic nephroma, especially from the more common Wilms tumor, solely based on imaging remains difficult. Recently, magnetic resonance imaging (MRI) has become the preferred modality. Studies focusing on MRI characteristics of congenital mesoblastic nephroma are limited.
Objective
This study aims to identify diagnostic MRI characteristics of congenital mesoblastic nephroma in the largest series of patients to date.
Materials and methods
In this retrospective multicenter study, five SIOP-RTSG national review radiologists identified 52 diagnostic MRIs of histologically proven congenital mesoblastic nephromas. MRI was performed following SIOP-RTSG protocols, while radiologists assessed their national cases using a validated case report form.
Results
Patients (24/52 classic, 11/52 cellular, and 15/52 mixed type congenital mesoblastic nephroma, 2/52 unknown) had a median age of 1 month (range 1 day–3 months). Classic type congenital mesoblastic nephroma appeared homogeneous with a lack of hemorrhage, necrosis and/or cysts, showing a concentric ring sign in 14 (58.3%) patients. Cellular and mixed type congenital mesoblastic nephroma appeared more heterogeneous and were larger (311.6 and 174.2 cm³, respectively, versus 41.0 cm³ for the classic type (P<0.001)). All cases were predominantly T2-weighted isointense and T1-weighted hypointense, and mean overall apparent diffusion coefficient values ranged from 1.05–1.10×10⁻³ mm²/s.
Conclusion
This retrospective international collaborative study showed classic type congenital mesoblastic nephroma predominantly presented as a homogeneous T2-weighted isointense mass with a typical concentric ring sign, whereas the cellular type appeared more heterogeneous. Future studies may use identified MRI characteristic of congenital mesoblastic nephroma for validation and for exploring the discriminative non-invasive value of MRI, especially from Wilms tumor.
Graphical Abstract
Pediatric renal tumors are among the most common pediatric solid malignancies. Surgical resection is a key component in the multidisciplinary therapy for children with kidney tumors. Therefore, it is imperative that surgeons caring for children with renal tumors fully understand the current standards of care in order to provide appropriate surgical expertise within this multimodal framework. Fortunately, the last 60 years of international, multidisciplinary pediatric cancer cooperative group studies have enabled high rates of cure for these patients. This review will highlight the international surgical approaches to pediatric patients with kidney cancer to help surgeons understand the key differences and similarities between the European (International Society of Pediatric Oncology) and North American (Children's Oncology Group) recommendations.
Introduction and importance
Malignant rhabdoid tumor of kidney (MRTK) is almost exclusive to children. Only 10 cases of adult MRTK have been reported. Here, we present a case of MRTK in an adult patient and discuss its clinical findings, diagnostic challenges, and treatment outcome. We also perform literature review on this issue.
Case presentation
Our patient was a 29-year-old woman presented with fever and hematuria. She also mentioned atypical teratoid/rhabdoid tumor of cerebellum in her deceased child. Initial diagnostic work up led to left partial nephrectomy with the pathology report of high grade undifferentiated tumor. Early tumor recurrence necessitated left radical nephrectomy with extensive excision of adjacent tissues. Pathology for second specimen considering disease course and family history was MRTK. Even though chemotherapy was administered, she died few months later due to multiple metastases.
Clinical discussion
Although diagnosis is challenging in all 11 reported cases –including our case- of adult MRTK, immunohistochemistry (i.e., negative reaction for INI-1) in conjunction with clinical and radiological findings are the main tool to reach diagnosis. Treatment options are much more diverse, ranging from surgery to immunotherapy, tyrosine kinase inhibitors, chemotherapy, and combination of these modalities. Prognosis remains dismal with the mean survival period of 7 months.
Conclusion
Although extremely rare, MRTK might happen in adults. We report the first case of adult MRTK with positive family history of rhabdoid tumor of CNS, underscoring the importance of family history in reaching the diagnosis and highlighting the role of genetics in this rare disease.
