Examples of the diagnostic utility of USP6 FISH in soft tissue and bone pathology

Background: The recognition that several entities previously considered to be reactive, bear rearrangements of the USP6 (ubiquitin-specific protease) gene, has transformed our understanding of the pathogenesis of lesions such as nodular fasciitis, aneurysmal bone cyst and myositis ossificans. These are now considered to be ‘benign self-limited neoplasms’. Each of these entities can mimic malignant neoplasms clinically, radiologically and on cytology and histology.