Colposcopy

Question 1

describe the histogenesis of the transformation zone

Answer 1

Exposure of sensitive columnar epithelium or ectropion to the post-pubertal acidic environment of the vagina induces squamous metaplasia and a transformation zone between the endocervical columnar epithelium and the ectocervical squamous epithelium. This zone is composed of new squamous epithelium in an area previously occupied by columnar epithelium.

Question 2

List the features of an unsatisfactory colposcopy assessment

Answer 2

Entire transformation zone is not visualised due to:
- TZ being inside the cervical canal (in postmenopausal women due to estrogen deprivation)
- cervical stenosis may prevent visualisation of TZ in endocervical canal
- obscured by blood or mucous
- radiation or previous cervical surgery may shorten and distort the cervix
Not being able to visualise the upper limit of a lesion

Question 3

list the possible colposcopic features of a high grade lesion

Answer 3

smooth surface with sharp outer border
dense acetowhite changes that appear early and are slow to resolve
coarse punctation and wide irregular mosaics of differing size
iodine negative with yellow areas in an area that was densely white after application of acetic acid
able to visualise abnormalities with green light filter