Figure 2.

The renal mass consisting of sheets of undifferentiated mesenchymal cells (H&E, 2a), and scattered well demarcated islands of differentiated cartilage (H&E, 2b). Both the undifferentiated tumor cells and cartilaginous islands were immunoreactive to Vimentin (2c), to S-100 protein (2d) and to CD99 (2e), and not to cytokeratin (2f).