Fig. 3

Histological examination: (A) high-power view showing simple papillary architecture lined by columnar epithelium in a double layer with oncocytic differentiation (similar to WT). Small collections of lymphocytes (patchy and limited) are present, but there is no lymphoid stroma (in contrast with WT). (B) There is no complex architecture, cytological atypia, mitotic activity, or invasive growth pattern. (C) p63 positivity highlights the basal cell layer at immunohistochemical stains. (D) Negativity for SOX10 and S100#