Pleomorphic cells with abnormal cytoplasmic and nuclear morphology infiltrating the nonneoplastic brain parenchyma showed EGFR-positive expression (buffy), and they had strongly acidophilic cytoplasm, high nucleus to cytoplasm ratio, and nuclear and cytoplasmic abnormal morphology, indicating that the pleomorphic cells were tumor cells (Figure 5). Here, EGFR is linked to neoplasm.