Cervical Cytology
Infection, Inflammation regeneration and repair
 
Human papillomavirus infection is characterised in cervical smears by the presence of koilocytes which are pathognominic for this infection. Koilocytes are mature  squamous cells with a characterisitic clear halo surrounding the nucleus.The halo is well defined and surrounded by a sharp edge of eosinophilic cytoplasm .The nuclei may be multiple and are slightly enlarged reflecting viral replication. According to the Bethesda System  smears containing koilocytes are classified as ASC-US or LSIL .