A, Cervical intraepithelial neoplasia (CIN) 1 with mild dysplasia and human papillomavirus (HPV) cytopathic effect with diffuse signal pattern of HPV staining (NBT/BCIP substrate with nuclear fast red counterstain, ×100). B, CIN 2 with moderate dysplasia and HPV cytopathic effect with diffuse signal pattern of HPV staining (NBT/BCIP substrate with nuclear fast red counterstain, ×400). C, Endocervical adenocarcinoma. In situ hybridization is positive for high-risk HPV types in rare adenocarcinoma cells and negative in benign endocervical glands. There is moderate dysplasia and HPV cytopathic effect with diffuse signal pattern of HPV staining (NBT/BCIP substrate with nuclear fast red counterstain, ×400).