Pap Smear

The Pap smear is used to screen for cervical cancer. This is accomplished by gathering cells from the cervix and searching for dysplasia, or pre-cancerous changes. In normal cells the cytoplasm appears much larger than the nucleus. Dysplastic cells have reduced cytoplasm, and increased ratio of nucleus to cytoplasm. This image contrasts normal cells with cells from low-grade and high-grade intraepithelial lesions. Low-grade lesions are often caused by papillomavirus infections and usually resolve spontaneously. High-grade lesions are indicative of cervical intraepithelial neoplasia or carcinoma in situ.