MKI67 and incontinentia pigmenti: Transitional and squamous epithelium showed significantly higher Ki-67 immunopositivity compared with columnar epithelium in IP (p < 0.05). Significantly higher expression rates of Ki-67 were present in dysplastic compared with non-dysplastic IP (p < 0.05). The difference between CIS and dysplastic IP and between SCC and CIS was not statistically significant. The expression rates of Ki-67 were comparable between NKCa and KSCC.