Pap Smears

The cervical pap smear is used to evaluate cells that have sloughed off of the surface of the cervix. A number of different devices can be used to collect these cells. The illustration shows one such device called a cytobrush which is shaped to collect a sample of cells from both the outer surface and inner canal of the cervix.American Cancer Society Recommendations for “Early Detection of Cervical Neoplasia and Cancer”
This is what normal cells obtained by a pap smear look like under the microscope. A special papanicolau stain is used to highlight the cytoplasm and nucleus of the cells so that any abnormalities are obvious.
The clump of large dark staining cells in the center of this pap smear are a good example of a “high grade squamous intraepithelial lesion” (HGSIL). This finding often correlates with the presence of a pre-malignant lesion on the surface of the cervix. A pap smear like this always needs to be aggressively evaluated with a colposcopic examination.
Colposcopes come in a variety of different shapes and sizes. All of these instruments consist of a magnifying viewfinder and a bright light source. The cervix is visualized during a pelvic exam and stained with acetic acid (vinegar). The acetic acid causes pre-malignant areas to exhibit a series of characteristics that can tell the gynecologist the location, size and severity of the lesion.
This is what a gynecologist sees when looking through a colposcope at a cervix which has already been exposed to acetic acid. The opening, or os, of the cervix is in the upper right hand corner and the vaginal wall is on the left side of the picture. You can see patchy white areas on the cervix that vary in their degree of “whiteness”. If you look closely you can also see some little red dots, or punctations, within the “acetowhite” areas. These and other characteristics suggest that a pre-malignant change has taken place. A biopsy should be performed to prove this presumption.
This cervical biopsy specimen shows a normal epithelium (the thin covering layer of the cervix) and a normal stromal layer (at the bottom of the picture). The separation between the two layers is formed by a well demarcated “basement membrane”.
Contrast this biopsy specimen to the one above. The epithelium is piled up in places and the basement membrane is not as well seen. The dark blue color of the epithelium on the left side of the picture is caused by large, irregular (pleomorphic) nuclei within the cells. This is a picture of a pre-malignant change called cervical intraepithelial neoplasia grade 3 (CIN III).