The mass was percutaneously biopsied which revealed "Spindle cell proliferation with metaplastic ossification, favor benign/reactive." 

FISH DNA Break-apart signal analysis for detection of USP6 translocation showed positive Break-apart signals in a large subset of the lesional spindle cells (50%). The finding implicates translocation involving USP6 and supports the diagnosis of nodular fasciitis with ossification/myositis ossifican or soft tissue ABC.

Follow up imaging was recommended.