FAQ's
Pap Smear Interpretation Information
Classification of Squamous Cells on the Pap Test
Several different classification schemes have evolved over the years for characterizing Pap test results. Unfortunately, this is a continuing source of confusion. The outdated Class system originally developed by Dr. Papanicolaou has been replaced by the CIN grading system and the Bethesda System. CIN stands for cervical intraepithelial neoplasia and implies an underlying aberration in proliferation of cells. In most cases, this is a precancerous lesion that may be easily treated with nearly 100% cure. Both the CIN grading system and the Bethesda System are in widespread use today. The table below compares the various nomenclature used to classify squamous cell abnormalities seen on Pap test:
|
Classification
of Squamous Cell Abnormalities |
|||
| Description | CIN Grading | Bethesda System (1) (See 4 Below) | Class (outdated) |
| Normal | Normal | Normal | Class I |
| Atypia Reactive or Neoplastic | Atypia | ASCUS (2) | Class II |
| HPV | HPV | Low-Grade SIL (3) | Class II |
| Atypia with HPV | Atypia, "condylomatous atypia" and "koilocytic atypia" | Low-Grade SIL | Class II |
| Mild Dysplasia | CIN I | Low-Grade SIL | Class III |
| Moderate Dysplasia | CIN II | High-Grade SIL | Class III |
| Severe Dysplasia | CIN III | High-Grade SIL | Class III |
| Carcinoma in-situ | CIS | High-Grade SIL | Class IV |
| Invasive Cancer | Invasive Cancer | Invasive Cancer | Class V |
|
|||
- 1. Kurman, R.J., Solomon D. The Bethesda System for reporting cervical/vaginal cytologic diagnoses, Springer-Verlag, New York, 1994
- 2. ASCUS: Atypical squamous or glandular cells of undetermined significance should be qualified further, if possible, as to whether a reactive or neoplastic process is favored.
- 3. SIL: Squamous intraepithelial lesion.
- 4. There will be a Bethesda III conference May, 2001 to further review and modify The Bethesda System (TBS).
Classification of Glandular Cells on the Pap Test
Glandular abnormalities are more difficult to classify. Glandular cells that are seen on the Pap test most commonly come from the endocervix. However, other glandular epithelial surfaces in the female reproductive tract may shed cells that are visible on the Pap test. Endometrial cells may appear on Pap tests and reveal underlying abnormalities. Because the female reproductive tract is open to the abdominal cavity via the Fallopian tubes, occasionally, cells from the ovary, Fallopian tubes, peritoneum or other interabdominal organs may be seen on the Pap smear. Glandular cells on the the Pap test are classified as follows:
- Endometrial cells, cytologically benign, in a postmenopausal woman
- Atypical glandular cells of undetermined significance (AGUS) that should be qualified further, if possible, as to whether a reactive or neoplastic process is favored.
- Endocervical Adenocarcinoma
- Endometrial Adenocarcinoma
- Extrauterine Adenocarcinoma (e.g. ovarian, Fallopian tube, pancreas, etc.)
- Adenocarcinoma, not otherwise specified (i.e. unknown primary site)
The cervix is the part of the uterus that extends into the vagina. There are two types of cells which line the cervix, one lines the outer cervix (portio) and another lines the inner cervix (endocervix). There is a distinct junction between the two cell types called the transformation zone. The Pap test is taken from this area because this where dysplasia (pre-cancer) and cancer most often arise.
Two common changes in cells are metaplasia and dysplasia.
Metaplasia - Metaplasia is generally described as a process of cell growth or cell repair which is benign (not cancerous). This process normally occurs in unborn babies, during adolescence, and with the first pregnancy. Studies have shown that metaplasia is present in more than one half of all women at some point in their development.
Dysplasia - In dysplasia, there is an increase in the number of cells formed, which do not mature as expected. This changes the inside of the cell. The higher the grade of dysplasia found on the cervix, the more likely that it will progress to invasive cancer. For this reason, dysplasia is thought as a "pre-cancerous" condition. Dysplasias are nearly 100% curable if managed appropriately. A small proportion of mild dysplasias (CIN I or low-grade SIL) will regress without treatment. However, it is not possible distinguish between dysplastic areas of the cervix that will return to normal and dysplastic areas which will progress and ultimately become cancer.
Causes of Cervical Cell Changes
Inflammation often results in mildly abnormal Pap tests. These may result in the diagnosis of CIN I in the CIN grading system, ASCUS in the Bethesda System or changes consistent with Human Papilloma Virus (HPV) infection. An inflamed cervix may appear red, irritated, or eroded. Some of the common causes of cervical inflammation are:
- 1. bacteria (from an infection)
- 2. viruses, especially herpes infections and condyloma cuminata (warts)
- 3. yeast or monilia infections
- 4. trichomonas infections
- 5. pregnancy, miscarriage, or abortion
- 6. chemicals (for example, medications)
- 7. hormonal changes
Colposcopy: The next diagnostic step
All abnormal Pap smears require further evaluation. If the abnormality is minor (i.e. inflammation, or HPV changes) your healthcare provider may choose to repeat the Pap test in a few months. If the abnormalities have persisted or worsened, colposcopy is indicated. Colposcopy will enable your physician or nurse to make a more accurate diagnosis. Management is individual and should be discussed with your physician or nurse.
Colposcopy - A colposcope is a lighted microscope that is used to magnify the cervical tissue during a pelvic examination. The colposcope is used to visualize abnormal areas of the cervix and vagina which are too small to see with the naked eye. The entire transformation zone must be seen. The colposcopic examination is an office procedure and is no more uncomfortable than a routine pelvic examination. It takes 5 to 10 minutes to perform. During the examination, the examiner may take small samples of cervical tissue (biopsies). Another specialist, a pathologist, will examine the tissue samples and cells. These diagnostic biopsies will guide further management.
The Pap smear is a screening test and not an individual diagnostic test by itself. The success of the Pap smear in screening for cervical cancer is through the repeated annual use of the Pap smear. The Pap smear is the single most successful cancer screening test in the history of Pathology. However, the Pap smear is not 100% accurate. It is only through the repeated use of annual Pap smear screens that the Pap smear is most successful as a screening procedure for cervical cancer. Additional cervical cancer screen technology such as the liquid based Thin layer (ThinPrep) Pap test and the HPV Hybrid capture II test may further aid your clinician in screening you for cervical cancer disease and determining future risk.
If you are sexually active or have had multiple sexual partners in your life, are a smoker, have not had a Pap smear for the past three years, come from a country where there were no cervical cancer screening programs or have had a sexually transmitted infection (STI), you may be at increased risk for cervical cancer disease. Remember to contact your physician and go in for your regular Pap smear. Early Detection saves lives! Caught early, cervical cancer is almost 100% curable! (Oncolink; modified by the National Cervical Cancer Coalition (NCCC). 12-2001.
