CD99 and sarcoma: Conversely, the morphological features associated with a peculiar immunoprofile (variable CD99 staining with frequent WT1 and ETV4 positivity in CIC-rearranged sarcomas, and immunoexpression of BCOR, SATB2, and cyclin D1 associated with a positivity of CD99 in approximately 50% of cases) allow the pathologist to distinguish these small round cell sarcomas of bone.