Diagnostic MRI characteristics of pediatric clear cell sarcoma of the kidney and rhabdoid tumor of the kidney: A retrospective multi-center SIOP-RTSG Radiology panel study

• DOI: 10.1016/j.ejcped.2023.100122
• Publication Date: 2023-11-04T03:55:51Z
• Authors: Justine N. van de...; Jens-Peter Schenk; Tom A. Watson; Ana Coma; Carlo Morosi; Norbert Graf; Tanzina Chowdhury; Gema L. Ramírez-V...; Filippo Spreafico; Kristina Dzhuma; Lidwine B. Mokkink; Ronald R. de Krijger; Marry M. van den ...; Annemieke S. Litt...
• Keywords: Wilms tumor; Neoplasms. Tumors. Oncology. Including cancer and carcinogens; Pediatrics; 03 medical and health sciences; Magnetic resonance imaging; 0302 clinical medicine; Oncology; Dentistry (miscellaneous); Rhabdoid tumor; Kidney neoplasms; Radiology; Clear cell sarcoma; RC254-282

Introduction: Clear cell sarcoma of the kidney (CCSK) and rhabdoid tumor of the kidney (RTK) are rare malignant pediatric renal tumors, both accounting for 1–5% of diagnoses. Within the International Society of Pediatric Oncology-Renal Tumor Study Group (SIOP-RTSG) protocols diagnostic invasive procedures to determine histology are discouraged. MRI has become the preferred imaging modality, however, non-invasive discrimination of CCSK and RTK remains challenging. Therefore, this study aims to identify diagnostic MRI-characteristics of CCSK and RTK, in the largest series of patients to date. Material and methods: Five SIOP-RTSG national review radiologists identified national diagnostic MRIs of histologically proven CCSKs and RTKs. Scan-protocols were based on MRI-guidelines following SIOP-RTSG protocols. Radiologists assessed their national cases using a validated case report form (CRF). Results: Retrospectively, 59 patients were identified (n = 38 CCSK, n = 21 RTK). CCSKs showed a high median volume (576 cm3, range 54–4414), which was lower for RTKs (290 cm3, range 20–761) (p = 0.006 *10-3). Fifty-two percent (11/21) of RTK-patients showed disease at other locations, predominantly the lungs and brain, compared to 8% of CCSK-patients (3/38). RTKs showed ill-defined margins (12/21, 57%) and infiltrative growth pattern (13/21, 62%). CCSKs appeared hyper-intense on T2-weighted imaging (27/38, 71%) with a characteristics band-like enhancement (13/38, 34%), whereas RTK cases often showed T2-weighted hypo-intensity (11/21, 52%). The overall mean ADC-value for CCSK was 1.11 * 10-3 mm2/s (range 0.57–2.07 *10-3 mm2/s), and 0.72 * 10-3 mm2/s (range 0.53–0.90 *10-3 mm2/s) for RTK. Conclusions: This retrospective study suggests a small size, T2-weighted hypo-intensity and an aggressive growth pattern may be characteristic for RTK. CCSK often showed a typical band-like enhancement pattern with relatively high ADC-values. Identified MRI-characteristics may be used in future studies focusing on validation and discrimination from especially WT, aiming for an early non-invasive diagnosis.