Primary aneurysmal bone cyst with a novel SPARC-USP6 translocation identified by next-generation sequencing

Aneurysmal bone cyst (ABC) is a benign but locally aggressive, mostly pediatric neoplasm, with characteristic USP6 gene rearrangement that distinguishes it from a secondary ABC and other primary bone tumors. With the advent of next-generation sequencing (NGS) technology, several hitherto unknown USP6 fusion partners have been identified in ABC. Accordingly, we present a case of an 18-year-old male with a solid sub-periosteal primary ABC in the diaphysis of the left femur. Using an NGS-based assay, we identified SPARC-USP6 fusion, which has not previously been described in ABC. Including our case, the list of currently known USP6 fusion partners in primary ABC include: CDH11, CNBP, COL1A1, CTNNB1, EIF1, FOSL2, OMD, PAFAH1B1, RUNX2, SEC31A, SPARC, STAT3 and THRAP3.