WT1 and clear cell sarcoma of kidney: It has been reported that immunohistochemical analysis is helpful to distinguish CCSK from other renal tumors in children because CCSK is often positive for Vimentin and Bcl-2 but negative for S-100, desmin Syn, WT-1, EMA, CD34, and CD99.[15] The immunohistochemical results for this patient were consistent with these results.