Fig. 2

Photomicrographs showing histopathology of the left insular tumor. Tumor cells presenting nuclear atypia such as small and semicircular nuclei were increased in number with microcystic stroma. No mitotic cells were observed (hematoxylin and eosin ×400, scale bar: 50 μm) (a). Immunohistochemistry for MIB-1 showing a very low Ki-67 (MIB-1) proliferation-related labeling index (1 % or less) (b). Immunohistochemistry for p53 (c) and epidermal growth factor receptor (EGFR) (d) revealing sporadic immunoreactivity of tumor cells for p53, but no immunoreactivity for EGFR. b–d ×400, scale bar: 50 μm