(a)
(b)

Figure 5: (a) Immunohistochemistry: desmin, lesional cells diffusely immunoreactive (20X). (b) Fluorescence in situ hybridization with a dual-color break-apart probe flanking the EWSR1 gene on chromosome 22q12. A separate red and green signal indicates a rearrangement involving EWSR1 and is identified in the lesional cells (100X).