Cervical screening Flashcards
what is the abnormal growth of squamous cells detectable on a smear called?
squamous intraepithelial lesion (SIL). Abnormal cells in the cervix detected by biopsy and histological examination are classified as cervical intraepithelial neoplasia (CIN). Graded 1 to 3 according to the proportion of cervix affected.
outline the UK HPV immunisation programme
2 dose regime of 16/11/18/6 Quadrivalent vaccine
what age is it started at?
25
Taking Screening Sample - how is this taken?
5 yearly smears , Liquid Based Cytology (LBC), Test for high risk HPV, If positive; triage with cytology
what is a HPV test?
Molecular test on cells sampled from cervix, Identifies high risk type HPV viral DNA or RNA, Any high risk type →→type specific genotyping, Works on LBC samples,
Technology: Hybridisation, PCR
what is a cervical cytology sample?
Microscopic assessment of cells scraped from the transformation zone, Look for abnormal cells (dyskaryosis), indicate that woman has underlying cervical intraepithelial neoplasia - CIN
what are the 2 components of the cervical canal?
endocervix - columnar epithelium, ectocervix - squamous epithelium
The majority of cells present are
mature squamous cells,
what method is the slide stained by
The slide is then stained by the Papanicolaou method for viewing under the microscope.
where are women reffered after a abnormal smear is detected?
for a colposcopy
Dyskaryosis has what features?
abnormal cells, Nuclear features: increased size and nuclear:cytoplasmic ratio, variation in size, shape and outline, coarse irregular chromatin, nucleoli
what do Koilocytes reflect?
HPV infecition
how do HPV tests and cytology differ?
HPV - cervical cells, machine, indentifies infection which could be transient or CIN associated, sensitive.
Cytology - cervicl cells, human interpretation, indentifies cellular chhanges (low grade - persisting infection/CIN1, high grade - CIN 2/3), specific.
what happens if +ve hrHPV?
if cytology is normal repeat the test in 1 year BUT if the cytology shows dyskaryosis then refer to colposcopy
what is a Colposcopy?
Colposcopy is a medical diagnostic procedure to examine an illuminated, magnified view of the cervix as well as the vagina and vulva. Many pre-malignant lesions and malignant lesions in these areas have discernible characteristics that can be detected through the examination.
what is it used for and how is it done?
excluding obvious malignancy, magnificaiton and light to see the cervix, use of acetic acid/ iodene to identify areas to treat, identify limits of the lesion, select the biopsy site. PUNCH BIOPSY DONE TO MAKE A DIAGNOSIS. Return for tx if CIN2/3
what is the action of HPV in the transformation zone?
infects the basal layer, utilises the host for replication, as the host cell matures different viral genes are expressed.
describe the histology of HPV infection of koliocytosis
cells wit wrinkled nuclei and periuclear halo. Multinucleation
which are low risk HPV types?
6, 11, 42, 44 - geital warts ad low grade CIN, ofte trasient ad resolve.
which are high risk HPV types?
16, 18, 31, 45, persistent infection increases the risk of developing high grade CIN and more cancer.
how does HPV cause high grade CIN?
persistent infection, viral DNA integrates into the host cell genome, overexpressio of viral e6 ad e7 protein, deregulation of the host cell cycle.
histology of CIN3
Neoplastic cells or undifferentiated cells fill full thickness of epith here , no normal differentiated cells seen
summarise what CIN is…
Disorganised proliferation of abnormal cells in squamous epithelium (dysplasia), Lack of maturation, variation in cellular size and shape, nuclear enlargement, irregularity, hyperchromasia, cellular disarray, CIN 1: low grade dysplasia–will regress, CIN 2: moderate dysplasia – may regress, CIN 3: severe dysplasia – unlikely to regress, Precursor of invasive cancer, it is invisible to the naked eye.
how is CIN treated?
LLETZ, Thermal Coagulation, Laser ablation
