Whole-tumor apparent diffusion coefficient measurements in nephroblastoma: Can it identify blastemal predominance?

PURPOSE: To explore the potential relation between whole-tumor apparent diffusion coefficient (ADC) parameters in viable parts of tumor and histopathological findings in nephroblastoma. MATERIALS AND METHODS: Children (n = 52) with histopathologically proven nephroblastoma underwent diffusion-weighted magnetic resonance imaging (MRI) (1.5T) before preoperative chemotherapy. Of these, 25 underwent an additional MRI after preoperative chemotherapy, shortly before resection. An experienced reader performed the whole-tumor ADC measurements of all lesions, excluding nonenhancing areas. An experienced pathologist reviewed the postoperative specimens according to standard SIOP guidelines. Potential associations between ADC parameters and proportions of histological subtypes were assessed with Pearson's or Spearman's rank correlation coefficient depending on whether the parameters tested were normally distributed. In case the Mann-Whitney U-test revealed significantly different ADC values in a subtype tumor, this ADC parameter was used to derive a receiver operating characteristic (ROC) curve. RESULTS: The 25(th) percentile ADC at presentation was the best ADC metric correlated with proportion of blastema (Pearson's r = -0.303, P = 0.026). ADC after preoperative treatment showed moderate correlation with proportion stromal subtype at histopathology (r = 0.579, P = 0.002). By ROC analysis, the optimal threshold of median ADC for detecting stromal subtype was 1.362 × 10(-3) mm(2) /s with sensitivity and specificity of 100% (95% confidence interval [CI] 0.65-1.00) and 78.9% (95% CI 0.57-0.92), respectively. CONCLUSION: ADC markers in nephroblastoma are related to stromal subtype histopathology; however, identification of blastemal predominant tumors using whole-tumor ADC measurements is probably not feasible. Level of Evidence 3 J. Magn. Reson. Imaging 2016;00:000-000

Characteristics and outcome of pediatric renal cell carcinoma patients registered in the International Society of Pediatric Oncology (SIOP) 93‐01, 2001 and UK‐IMPORT database: A report of the SIOP‐Renal Tumor Study Group

In children, renal cell carcinoma (RCC) is rare. This study is the first report of pediatric patients with RCC registered by the International Society of Pediatric Oncology‐Renal Tumor Study Group (SIOP‐RTSG). Pediatric patients with histologically confirmed RCC, registered in SIOP 93‐01, 2001 and UK‐IMPORT databases, were included. Event‐free survival (EFS) and overall survival (OS) were analyzed using the Kaplan‐Meier method. Between 1993 and 2019, 122 pediatric patients with RCC were registered. Available detailed data (n = 111) revealed 56 localized, 30 regionally advanced, 25 metastatic and no bilateral cases. Histological classification according to World Health Organization 2004, including immunohistochemical and molecular testing for transcription factor E3 (TFE3) and/or EB (TFEB) translocation, was available for 65/122 patients. In this group, the most common histological subtypes were translocation type RCC (MiT‐RCC) (36/64, 56.3%), papillary type (19/64, 29.7%) and clear cell type (4/64, 6.3%). One histological subtype was not reported. In the remaining 57 patients, translocation testing could not be performed, or TFE‐cytogenetics and/or immunohistochemistry results were missing. In this group, the most common RCC histological subtypes were papillary type (21/47, 44.7%) and clear cell type (11/47, 23.4%). Ten histological subtypes were not reported. Estimated 5‐year (5y) EFS and 5y OS of the total group was 70.5% (95% CI = 61.7%‐80.6%) and 84.5% (95% CI = 77.5%‐92.2%), respectively. Estimated 5y OS for localized, regionally advanced, and metastatic disease was 96.8%, 92.3%, and 45.6%, respectively. In conclusion, the registered pediatric patients with RCC showed a reasonable outcome. Survival was substantially lower for patients with metastatic disease. This descriptive study stresses the importance of full, prospective registration including TFE‐testing

Two cases with partial trisomy 9p:Molecular cytogenetic characterization and clinical follow-up

This paper describes two patients with partial trisomy 9p and partial trisomy 14q due to 3:1 segregation from de novo maternal reciprocal translocations. The breakpoints are different from previously described 9;14 translocations and their 3:1 segregation products. The clinical phenotype of both cases is compatible with the partial trisomy 9p syndrome. We present the follow-up of both patients from birth up to age 7 years. Partial trisomy 9p is a frequently described chromosome abnormality. This does not appear to be related to a breakage sensitive locus on chromosome 9p, since the trisomic fragments of the published cases are heterogeneous. In the two cases described here, GTG-banded karyotyping suggested that the 9p breakpoints were similar; DNA marker analysis, however, showed them to be different. Such DNA studies will be necessary to define the genotype-phenotype relation in partial trisomy 9p syndrome. (C) 2002 Wiley-Liss, Inc