Gynaecological Cytology consists of exfoliated cells sampled from the female genital track, namely the cervix. This screening test is performed on the healthy female population to find early stage disease caused by the HPV virus.
There are 2 basic cell types seen on a cervical smear, these are squamous cells and endocervical/glandular cells. The HPV virus can affect both of these cell types and if left untreated can eventually lead to malignancy.
According to the Bethesda system for reporting cervical cytology, cervical lesions are broken down in to the following categories:
- Squamous cell carcinoma
- Glandular lesion
The images provided can be used as a general guidance to their presentation on a cervical smear prepared using NOVAprep® technology.
There will be times where an accurate diagnosis cannot be given due several limiting factors:
• Insufficient tissue sampled
• A full representation of the cervix is not present
• Poor fixation
The presence of several physiological and non-physiological contaminants can lead to an inaccurate diagnosis.
The physiological contaminants are blood, mucus and inflammatory cells, as they can completely obscure the tissue needed for diagnosis.
The Non-physiological factors, are not limited to, but mainly consist of lubricant, talc & sperm.
Contaminants such as these can lead to a false negative or false positive report.
Glandular lesions are abnormalities of the endocervix, they can also be extracervical mainly from the endometrium and ovaries.
On cytology it can be very difficult to distinguish between in-situ lesions and frankly invasive lesions, therefore it has been determined that the category AGC should be broad and all encompassing.
Diagnosis of an invasive lesion should always be made histologically.
Squamous lesions form the bulk of the abnormalities detected in the cervical screening program. There are 2 definitive categories and 2 ambiguous categories due to the variation in interpretation of the subtle nuclear changes that are observed.
The definitive categories are LSIL and HSIL: LSIL (low grade squamous intraepithelial lesions) are reserved for abnormal nuclear changes in mature squamous cells. HSIL (high grade squamous intraepithelial lesions) are reserved for abnormal nuclear changes in immature squamous cells
The Ambiguous lesions can be broken down into 2 categories, ASC-US ( Atypical Squamous Cells of Undertermined Significance) and ASC-H (Atypical Squamous cells High grade).
ASC-US is reserved for cells that are showing changes that could either be linked to a low grade disease, an infective organism or simply reactive changes. ASC-H is normally reserved for cells that are showing changes that could equate to HSIL.
Squamous cell carcinoma of the cervix is the invasive lesion of the ectocervix
As cervical cytology is a screening test, a very high percentage of cases fall into this category. A cervical smear should consist of squamous cells and a sampling of the transformation zone (TZ).
The TZ consists of metaplastic cells where it is believed most abnormalities begin. For a complete picture of the cervix, endocervical cells should also be present.
The images are a representation of what negative samples can be seen using the NOVAprep® technology
Gynecological cytology is not diagnostic for micro-organisms, but it is possible to identify several microbial infections in gynecological LBC samples:
* Trichomonas vaginalis
* Candida species
* Herpes simplex virus
* Actinomyces species
* Lactobacilli and coccobacilli
The absence of a microbe from a gynecological LBC sample does not conclusively prove that the patient does not have an infection.