Clear cell sarcoma of the kidney (CCSK) is the second most common malignant pediatric renal tumor. Two of the recurrent somatic alterations reported in CCSK are BCL-6 corepressor (BCOR) internal tandem duplication (ITD) and YWHAE-NUTM2B/E gene fusion. A minority of patients with CCSKs have other rare somatic alterations. We report two patients with CCSK showing BCOR-CCNB3 (where CCNB3 is cyclin B3) fusion, who had similar clinical presentation of a large renal mass with tumor thrombus extending through the inferior vena cava into the right atrium and a favorable response to chemotherapy. We recommend BCOR-CCNB3 fusion testing for all patients with CCSK who lack BCOR-ITD or YWHAE-NUTM2B/E gene fusions.
Keywords: pediatric oncology; renal tumors; solid tumors.
© 2019 Wiley Periodicals, Inc.