Immunohistochemistry showed that the tumour was diffusely positive for CD99; focally positive for cyclin-D1, CD10, CD34, BCL2; and negative for cytokeratins, S100, HMB45, SMA, desmin, caldesmon, estrogen receptor (ER), progesterone receptor (PR), neuroendocrine markers, and gastrointestinal stromal tumour (GIST) markers. This evidence concerns the gene PMEL and gastrointestinal stromal tumor.