Sarcomas with EWSR1::Non-ETS Fusion (EWSR1::NFATC2 and EWSR1::PATZ1).

ABSTRACT

The wide application of increasingly advanced molecular studies in routine clinical practice has allowed a detailed, albeit still incomplete, genetic subclassification of undifferentiated round cell sarcomas. The WHO classification continues to include provisional molecular entities, whose clinicopathologic features are in the early stages of evolution. This review focuses on the clinicopathologic, molecular, and prognostic features of undifferentiated round cell sarcomas with EWSR1/FUSNFATC2 or EWSR1PATZ1 fusions. Classic histopathologic findings, uncommon variations, and diagnostic pitfalls are addressed, along with the utility of recently developed immunohistochemical and molecular markers.