Condyloma Acuminata : ISH
Human papillomavirus (HPV) can be demonstrated by immunohistochemistry as well as in-situ hybridization (ISH) techniques. This is not necessary in most cases but can resolve lesions with equivocal histopathology.
ISH panel is performed on formalin-fixed paraffin-embedded tissue and can include any of the following: low risk subtypes, high risk subtypes, or a complete panel with both subtypes.
This ISH image from an anal condyloma is positive for HPV DNA (high risk subtypes) in the nuclei of koilocytes. Studies have shown that RNA ISH has greater sensitivity and specificity than DNA ISH for HPV detection. RNA ISH involves detection of HPV E6/E7 mRNA. A positive result is evidence of transcriptional activation of viral E6/E7 oncogenes and supports the diagnosis of active HPV infection.