The Pap smear in inflammation and repair.

Cytology of the uterine cervix is one of the most widely utilized tests and is best known primarily for the cytologic changes seen in precancerous lesions and invasive cancer of the uterine cervix. The more common inflammatory conditions of cervicitis and vaginitis are close clinical differentials, especially when they give rise to excessive blood-stained vaginal discharge. These infective conditions also result in variation in the appearance of otherwise benign squamous and glandular cells in cervical cytology specimens. A variety of physiologic and pathologic conditions are responsible for the conversion of polymicrobial flora of the vagina to a monomicrobial one. The latter may overgrow the others and result in inflammation of the cervix and the vagina. Chronic irritation of the cervix due to intrauterine devices, chemical irritants, inflammation/infection, endocrine changes, and reparative changes can lead to worrisome parakeratosis, hyperkeratosis, and squamous metaplasia of non-keratinized squamous mucosa of the cervix and the vagina and may mimic HPV-related changes. Although some benign changes are specific for certain infections, for example, infestation, most of the reactive and hyperplastic cell morphology are important to recognize only due to the significant morphologic overlap with neoplastic changes in cytology specimens. Identification of different pathogens specifically may not be relevant from a clinical point of view, but is undoubtedly a cytologists' privilege to inform the clinician! This chapter describes in detail the cytoplasmic and nuclear reactive changes that are found in specific and non-specific inflammatory conditions. In addition, diagnostic pitfalls are emphasized where necessary.