cervical pathology Flashcards
explain the histological and cytological grading of precancerous cervical squamous lesions
histological:
- HPV, CIN 1, CIN 2, CIN3
cytological:
- low grade squamouns intraepithelial lesion (HPV and CIN1) and high grade squamous intraepithelial lesion (CIN2 and 3)
where is the highest incidence of cervical cancer in the world
south america, africa and india
explain the correlation between HPV and different types of cancers
cervical - 100% attributable to HPV
penile or vulval - about half
oropharyngeal - lowest proportion
what are the 2 highest risk HPV to go on for cervical cancer
16 and 18
which age group has the biggest prevalence of HPV infection
20-24
describe the structure of the HPV virus
dsDNA with capsid
explain the two classes of proteins that are made by HPV
early = encode for replication and viral proteins late = encode for capsid proteins
what type of cells does HPV infect
the immature basal cells of the squamous epithelium in areas of epithelial breaks or immature metaplastic squamous cells present at the squamo-columnar junction
explain what integration of the HPV genome into host DNA does
- during replication - a break point is introduced into the E2 gene (usually suppresses E6 and E7.
- break in E2 disrupts the gene which causes regulation of E 6 and E7 to be lost
- E6 binds to p53 and deactivates it
- E7 binds to Rb and disrupts its ability to halt cells at the restriction point
- allows neoplastic cells to proliferate
what proportions of HPV viral infections are cleared
50% are cleared within 8 months
90% are cleared within 2 years
which area of the cervix is most susceptible to dysplasia and HPV infection
the squamocolumnar transformation zone
what is a cervical condyloma
the cells are infected with HPV but hasn’t been integrated into the host genome - causing squamous cell layer thickening and keratinocytes can retain their nuclei
what defines CIN 1,2,3
CIN 1 = atypical changes involve only the lower 1/3 of the epithelium
CIN 2 = involves up to 2/3 of the epithelium
CIN 3= involves between 2/3 and the whole width of the epithelium
when does CIN 3 become squamous cell carcinoma
with invasion of the BM
what are the histological features of adenocarcinoma in situ
- nuclei haphazardly arranged
- numerous mitotic bodies
- apoptotic debris
- cells have lost polarity
- nuclei polymorphism
what do koliocytes look like
have large vacuole within the cell
what can you see on cytology for low grade and high grade squamous intraepithelial lesion
low = koliocytes high = markedly enlarged nuclei with minimal cytoplasm, pleomorphism more significant
what are the guidelines if a cervical smear is normal
repeat in 2 years
what are the guidelines if a cervical smear is unsatisfactory
repeat in 6-12 weeks
what are the guidelines if a smear has possible LSIL/LSIL
repeat pap test in 12 months
what are the guidelines if a smear is possible HSIL / HSIL / repeated LSIL
referral for colposcopic assessment
