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. Here, ESR1 is linked to gastrointestinal stromal tumor.