KRT5 and intraepithelial neoplasia: Deep incisional biopsies of the ulcer edge and sinus-tract wall demonstrated hyperkeratotic epidermis with pseudo-epitheliomatous hyperplasia overlying dense chronic inflammatory granulation tissue; no epithelial dysplasia or invasive squamous-cell carcinoma was seen on hematoxylin and eosin staining or on ΔNp63 (p40), p63 (TP63), and cytokeratin 5/6 (CK5/6) immunohistochemistry.