Multidisciplinary Fusion: A recurrent expansive prevertebral vascular anomaly with EWSR1::NFATC2 fusion

The field of vascular anomalies has seen a rapid paradigm shift from descriptive to molecular diagnoses, with DNA-based next-generation sequencing becoming standard practice in the workup and characterization of lesions. RNA-based panels for fusion transcripts have been less utilized in the field of vascular anomalies. We report a recurrent, infiltrative prevertebral vascular tumor negative for known somatic variants but positive for an Ewing sarcoma breakpoint region 1::nuclear factor of activated T-cells cytoplasmic 2 fusion transcript. This lesion demonstrated intermediate malignant potential with morphologic atypia, novel intraluminal endothelial growth, and atypical mitoses, which have not previously been reported. RNA-based panels for fusion transcripts may represent the next impactful evolution of molecular characterization of vascular malformations and tumors.