Non-Wilms' Renal Tumors In Children:A 139 Cases Series

Background:Pediatric non-Wilms renal tumors (NWRTs) which comprise a small proportion of renal tumors,are a heterogeneous group of neoplasms with variable malignant potential, mortality, and response to treatment.This study aimed to determine the clinical characteristics, management and prognosis of children with non-Wilms' renal tumors(NWRTs). Methods:Medical records of all patients (n = 139) treated for NWRTs over a 12-year period (2008.01–2019.10) at a single center were reviewed retrospectively.Results:The histopathological groups of NWRTs included malignant rhabdoid tumor of the kidney(MRTK)(n: 30, 21.6%), renal cell cancer(RCC)(n: 26,18.7%), clear cell sarcoma of the kidney(CCSK)(n: 24,17.3%), congenital mesoblastic nephroma(CMN)(n: 21,15.1%), cystic nephroma(CN)(n: 16,11.5%),metanephric tumours(n: 12, 8.6%), renal angiomyoliporma(RAML)(n: 3, 2.2%), renal primitive neuroectodermal tumor(rPNET)(n: 2, 1.4%), renal hemangioma(n: 2, 1.4%), inflammatory myofibroblastic tumor(IMT)(n: 2, 1.4%), ossifying renal tumor of infancy(ORTI)(n: 1, 0.7%). 123 children were followed up with an average of 42 months. 16 children were lost to follow-up. Tumor-free survival was observed in 94 children. 28 children(22.8%) were died.Conclusions:Pediatric NWRTs comprises 19.1% of all renal tumors in our single center. Accurate diagnoses along with appropriate management are important factors in improving patients outcome. The mainstay treatment of malignant NWRTs including MRTK,CCSK,RCC and PNET is comprehensive treatment. The mainstay treatment of benign NWRTs including RAML,CN, ORTI, CMN,metanephric tumours, and renal hemangioma is surgical resection alone.

Primary Sclerosing Epithelioid Fibrosarcoma of the Kidney: A Case Report and Review of the Literature

Sclerosing epithelioid fibrosarcoma (SEF) is a rare variant of fibrosarcoma. We report one case of primary kidney SEF occurring in a 38-year-old man. Microscopically, epithelioid neoplastic cells are mainly arranged in cords and nests embedded in the dense sclerosing stroma. Diffuse immunohistochemical staining for MUC4 in neoplastic cells and the presence of the EWSR1 gene split by fluorescence in situ hybridization (FISH) analysis confirmed the histological diagnosis. Primary kidney SEF is extremely rare, the differential diagnosis strategy broadly includes a series of tumors with epithelioid morphology and sclerosing matrix, mainly including sclerosing variants of clear cell sarcoma of the kidney (CCSK), renal synovial sarcoma (SS), renal solitary fibrous tumor (SFT), metanephric stromal tumor (MST), sclerosing perivascular epithelioid cell tumor (PEComa), and carcinomas, and immunohistochemical expression of MUC4 and evidence of the EWSR1 gene split are helpful in making a definite diagnosis.

Clear cell sarcoma of the kidney in children: clinical characteristics and treatment results

Clear cell sarcoma of the kidney (CCSK) is a rare malignant renal tumor in children, which accounts for 2–5% of pediatric kidney malignancies. The aim of the study was to analyze the results of therapy of patients with CCSK treated in Dmitry Rogachev National Medical Research Center оf Pediatric Hematology, Oncology and Immunology. Retrospective analysis of patients with a histologically confirmed diagnosis of CCSK treated for the period 01.2012–02.2020 (98 months) was done. The study was approved by the Independent Ethics Committee and the Scientific Council of the D. Rogachev NMRCPHOI of the Ministry of Healthcare of the Russian Federation. Demographic characteristics, clinical symptoms, methods of diagnosis, and treatment modalities were analyzed. Patients were treated according to the protocols of the SIOP-RTSG group (SIOP 93-01, SIOP-2001, SIOP-RTSG-2016). The stage was assigned according to the SIOP classification. Overall and event-free survival was assessed by the Kaplan–Mayer method. The analysis of the results was carried out on 01.03.2021. The analysis included 10 patients with CCSK. The median age at the time of diagnosis of CCSK was 30.1 months (range 13.5–70.8 months). All patients were male. The duration from the onset of the first symptoms/detection of the tumor to the diagnosis was 0.8 months (range 0.1–3.2 months). The diagnosis was established on the basis of clinical and radiological data (n = 9) and biopsy (n = 1). Distant metastases at the time of diagnosis were detected in 1 (10%) patient (localization of metastases - lungs). The median tumor volume was 439 cm3 (range 256–996 cm3 ). Preoperative chemotherapy was performed in all patients (AV regimen (actinomycin D, doxorubicin) in 7 (70%) patients). Assessment of response after preoperative chemotherapy showed tumor regression in 3/10 (in 1/7 with AV regimen), tumor progression in 5 and stable disease in 2 patients. Surgical treatment in the extent of nephrectomy was performed in all patients. In 1 (10%) case, intraoperative tumor rupture was documented. Distribution of patients by local stages: I – 4/10 (40%), II – 2/10 (20%), III – 4/10 (40%) (including 1 patient with distant metastases). In 1 patient, a left thoracotomy was performed to exclude lung metastases. Adjuvant chemotherapy was performed in all patients in accordance with the relevant protocols of the high-risk group: 7 – 4–5-drug regimen, 3 – AVD regimen (actinomycin D, vincristine, doxorubicin). Radiation therapy was performed in 6/10 (60%) patients. Outcomes: 9/10 (90%) – alive, 1/10 (10%) patient died (non-tumor-related death). 3-year event-free survival and overall survival were 78.8% (95% confidence interval (CI) 52.5–100) and 90.0% (95% CI 71.4–100) respectively. Intensive program therapy in patients with CCSK allows to achieve satisfactory results of treatment.

Histopathological and Molecular Profiling of Clear Cell Sarcoma and Correlation with Response to Crizotinib: An Exploratory Study Related to EORTC 90101 “CREATE” Trial

Clear cell sarcoma (CCSA) is characterized by a chromosomal translocation leading to EWSR1 rearrangement, resulting in aberrant transcription of multiple genes, including MET. The EORTC 90101 phase II trial evaluated the MET inhibitor crizotinib in CCSA but resulted in only sporadic responses. We performed an in-depth histopathological and molecular analysis of archival CCSA samples to identify alterations potentially relevant for the treatment outcome. Immunohistochemical characterization of MET signaling was performed using a tissue microarray constructed from 32 CCSA cases. The DNA from 24 available tumor specimens was analyzed by low-coverage whole-genome sequencing and whole-exome sequencing for the detection of recurrent copy number alterations (CNAs) and mutations. A pathway enrichment analysis was performed to identify the pathways relevant for CCSA tumorigenesis. Kaplan–Meier estimates and Fisher’s exact test were used to correlate the molecular findings with the clinical features related to crizotinib treatment, aiming to assess a potential association with the outcomes. The histopathological analysis showed the absence of a MET ligand and MET activation, with the presence of MET itself in most of cases. However, the expression/activation of MET downstream molecules was frequently observed, suggesting the role of other receptors in CCSA signal transduction. Using sequencing, we detected a number of CNAs at the chromosomal arm and region levels. The most common alteration was a gain of 8q24.21, observed in 83% of the cases. The loss of chromosomes 9q and 12q24 was associated with shorter survival. Based on exome sequencing, 40 cancer-associated genes were found to be mutated in more than one sample, with SRGAP3 and KMT2D as the most common alterations (each in four cases). The mutated genes encoded proteins were mainly involved in receptor tyrosine kinase signaling, polymerase-II transcription, DNA damage repair, SUMOylation and chromatin organization. Disruption in chromatin organization was correlated with longer progression-free survival in patients receiving crizotinib. Conclusions: The infrequent activation of MET may explain the lack of response to crizotinib observed in the majority of cases in the clinical trial. Our work describes the molecular heterogeneity in CCSA and provides further insight into the biology of this ultra-rare malignancy, which may potentially lead to better therapeutic approaches for CCSA.

Imaging features and differences among the three primary malignant non-Wilms tumors in children

Background The pathology, treatment and prognosis of malignant non-Wilms tumors (NWTs) are different, so it is necessary to differentiate these types of tumors. The purpose of this study was to review the clinical and imaging features of malignant NWTs and features of tumor metastasis. Methods We retrospectively analyzed the CT images of 65 pediatric patients with NWTs from March 2008 to July 2020, mainly including clear cell sarcoma of the kidney (CCSK), malignant rhabdomyoma tumor of the kidney (MRTK) and renal cell carcinoma (RCC). Available pretreatment contrast-enhanced abdominal CT examinations were reviewed. The clinical features of the patients, imaging findings of the primary mass, and locoregional metastasis patterns were evaluated in correlation with pathological and surgical findings. Results The study included CCSK (22 cases), MRTK (27 cases) and RCC (16 cases). There were no significant differences observed among the sex ratios of CCSK, MRTK and RCC (all P > 0.05). Among the three tumors, the onset age of MRTK patients was the smallest, while that of RCC patients was the largest (all P < 0.05). The tumor diameter of CCSK was larger than that of MRTK and RCC (all P < 0.001). For hemorrhage and necrosis, the proportion of MRTK patients was larger than that of the other two tumors (P = 0.017). For calcification in tumors, the proportion of calcification in RCC was highest (P = 0.009). Only MRTK showed subcapsular fluid (P < 0.001). In the arterial phase, the proportion of slight enhancement in RCC was lower than that in the other two tumors (P = 0.007), and the proportion of marked enhancement was the highest (P = 0.002). In the venous phase, the proportion of slight enhancement in RCC was lower than that in the other two tumors (P < 0.001). Only CCSK had bone metastasis. There was no liver and lung metastasis in RCC. Conclusions NWTs have their own imaging and clinical manifestations. CCSK can cause vertebral metastasis, MRTK can cause subcapsular effusion, and RCC tumor density is usually high and calcification. These diagnostic points can play a role in clinical diagnosis.

Clear Cell Sarcoma of Tendon and Aponeuroses with Excessive Melanin Production – An Unusual Presentation

Clear cell sarcoma of tendons and aponeuroses also called as malignant melanoma of soft parts is a rare tumor of neural crest origin with 70% of them possessing balanced translocation t(12; 22). Approximately 50% of the tumor produces melanin which often shows focal pigmentation or needs special stains to demonstrate melanin. Production of excessive melanin by this tumor is very unusual and very few case reports are available in literature. We report a case of Clear cell sarcoma with excessive melanin production in a 50-year-old female patient involving the left popliteal fossa.