Myoepithelial Tumor of Soft Tissue With the Novel IRF2BP2::CDX1 Gene Fusion

Myoepithelial tumors of soft tissue are mesenchymal tumors with characteristic gene fusions involving the EWSR1 or FUS gene in many cases. EWSR1-negative gene fusions are rarely reported in myoepithelial tumors of soft tissue. Herein, we report a novel gene fusion, IRF2BP2::CDX1, in a myoepithelial tumor of soft tissue in a 36-year-old female harboring rare morphologic findings, including multinucleated giant cells and microhemorrhages. Our case adds to the expanding pool of EWSR1-negative myoepithelial tumors of soft tissue. These rare tumors appear to share some histological features, including fascicular spindle cell arrangement with vascular changes. Our report further corroborates the clinicopathological characteristics and molecular features of such tumors.