BCOR‐CCNB3 fusion‐positive clear cell sarcoma of the kidney

Abstract

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.

Primary Renal <b><i>BCOR-CCNB3</i></b> Fusion Sarcoma: A Case Report and Review of the Literature

“…The clinical manifestations were nonspecific with most patients presenting with abdominal pain or hematuria. By imaging and gross studies, the tumors were usually large (range: 8.1–27 cm, median: 12.2 cm) and solid with variable cysts, with 3 cases having inferior vena cava involvements [6, 7].…”

“…Because this is only the ninth documented report of renal BCOR-CCNB3 fusion sarcoma, the optimal therapeutic regimen has not yet been defined, and the prognosis for this entity is largely unknown. Among the 9 cases reported, treatment information was available for 8 patients, 5 of whom experienced surgery alone and the remaining 3 received adjuvant chemotherapy (2 with CCSK regimen and 1 with Ewing regimen) with or without radiotherapy in addition to surgical resection [5, 6]. Follow-up (1–54 months) was available on 7 patients and one had abdominal recurrence 15 months after the surgery [3].…”

Primary Renal Sarcoma With BCOR-CCNB3 Gene Fusion in an 18-Year-Old Male: A Rare Lesion With a Diagnostic Quandary

“…Primary renal BCOR-CCNB3 fusion sarcoma is a rare entity that has recently been reported in 4 small case series. 2-5 All 7 cases have occurred in males (age range: 8-46 years; median age: 12 years). The majority of the patients presented with large renal masses (>12 cm), 2 of whom had inferior vena cava involvement.…”

“…The majority of the patients presented with large renal masses (>12 cm), 2 of whom had inferior vena cava involvement. 4 Follow-up was available in 5 patients and one case had abdominal recurrence 15 months after nephrectomy. The morphology varies but predominantly consists of uniform spindle to oval cells with swirling growth patterns.…”

“…1 Primary renal BCOR-CCNB3 sarcoma was consecutively reported in cohorts of clear cell sarcoma of the kidney (CCSK). 2,3 Several small case series have subsequently been published, 4,5 and a total of 7 cases, including 5 pediatric and 2 adult cases, have been described in the English literature. Accurate diagnosis can be challenging, because of the overlapping morphologic features and lack of awareness among practicing pathologists due to its rarity.…”