A 22-year-old woman has an abnormal cervical Pap smear. A biopsy is obtained from a suspicious area on the cervix. The pathology report says, "There is a loss of the normal orientation of the squamous cells. Atypical cells with wrinkled nuclei and perinuclear halos involve the full thickness of the squamous epithelium. The basement membrane is intact." Your diagnosis ?

The patient has cervical intraepithelial neoplasia (CIN) III with koilocytic atypia secondary to the human papillomavirus. The designation CIN III encompasses both severe dysplasia and carcinoma in situ. Cervical dysplasia is a precursor lesion of cervical squamous cancer. Most cases of cervical dysplasia oc­cur in women in their late 20s and 30s. The pathogene­sis of cervical dysplasia and cancer is an early age of first intercourse, multiple sexual partners, male partner(s) with multiple previous sexual panners, smoking, im­munosuppression (renal transplants, AIDS), a strong association with human papillomavirus (HPV) types 16, 18, 31, and herpes infection (possible cocarcinogen with HPV). Cervical intraepithelial neoplasia (CIN) is a system for classifying dysplasia into mild, moderate, severe, and carcinoma in situ. The histologic correlations to these designations include CIN I (mild dysplasia), which involves the innermost one third of the cervical epithelium; CIN II (moderate dysplasia), which involves two thirds the thickness of the epithelium; and CIN III (severe dysplasia or carcinoma in situ), which involves in the full thickness of the epithelium. Koilocytosis refers to squamous cells with wrinkled  nuclei surrounded by a perinuclear halo. It correlates with the presence of HPV. Colposcopy involves inspection of the cervix with a stereoscopic binocular microscope after the cervix has been saturated with acetic acid. It aids the clinician in identifying abnormal areas to biopsy.