A Pediatric Primary Cardiac Spindle Cell Neoplasm With a Rare PDGFRA::USP8 Gene Fusion: A Case Report.

We report a case of a primary cardiac spindle cell neoplasm with concerning histological features and a rare gene fusion in a 3 year old boy. The patient presented with a large cardiac mass predominantly in the right ventricle, originating from the ventricular septum. The mass was resected with grossly negative margins. Pathology revealed an unclassified spindle cell neoplasm with a gene fusion. This gene fusion has only been previously reported twice in the medical literature, one in a pediatric cardiac sarcoma and the other in an abdominal soft tissue tumor in an adult woman. The patient is alive and well with no evidence of recurrence 11 months after excision.