kristyn feldman histology.pdf

8/14/2019 Kristyn Feldman Histology.pdf

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Cervical Histologyand

Infectious Diseases

Kristyn Feldman


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Gross anatomy

! The cervix is actually the lower, narrow

portion of the uterus.! Its name is derived from the Latin word for

"neck."

! It is cylindrical or conical in shape.


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Why its interesting

! Since nearly all cervical neoplasia (abnormal

growth) occurs in the presence of HPV, thecervix provides the best-defined model of

virus-mediated carcinogenesis in humans to

date!

! Infectious disease + cancer


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Normal Histology

! The cervix is covered by both columnarand

stratified non-keratinising squamousepithelia.

! The squamocolumnar junction (SCJ),

where these two meet, is the most important

cytologic and colposcopic landmark, as thisis where over 90% of lower genital tract

neoplasia arises.


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Mature squamous epithelium (H&E x 400): Different layers starting at the

basement membrane (basal, parabasal, intermediate, superficial) are evident.

Clear cytoplasm indicates glycogenation. As the cells mature, the nuclei get

smaller and the cytoplasm amount increases.


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Glandular or Columnar Epithelium

! The glandularor columnar epithelium

! Covers a variable amount of the ectocervixand lines the endocervical canal.

! It is comprised of a single layer of mucin-secreting cells.

! Longitudinal folds and invaginations make upthe so-called endocervical glands(they arenot true glands).


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Endocervical glands (H&E x 400): Actually crypts lined by a single layer of

columnar epithelium. Extend to a depth of 5-7 mm.


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Changes in the SCJ

The location of the SCJ in relation to the anatomicexternal os varies with a variety of factors:

! At birth it is at or just above the external opening withthe original squamous epithelium outside and theendocervical columnar epithelium on the inside.

! With growth of the uterus, especially from pubertyand throughout reproductive life, the SCJ comes tolie at variable distancesbelow the anatomicexternal opening.


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The border between the stratified squamous epithelium of the ectocervix and the

columnar epithelium of the endocervix is called the squamocolumnar junction

(SCJ).


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The new SCJ

This is a continuous remodeling process that is alsoinfluenced by other factors, and occurs throughoutthe life of a female producing two different SCJs:

! Original SCJ: is the site at which the neonatalsquamous epithelium of the ectocervix meets theendocervical columnar epithelium at birth.

! New, functional or physiologic SCJ: newly formedSCJ as a result of the dynamic remodeling that takesplace during the life of the female.


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Endocervical ectropion. Note everted columnar epithelium, which is reddened and

looks like "eroded" tissue


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Transformation (transition) zone

! The area, formed by the metaplastic

squamous epithelium, between the old andthe new SCJ is called the transformation ortransition zone (TZ).

! The new SCJ, and hence the extent of theTZ, can be observed from the vagina.However, in up to 15% of women the TZextends into the endocervical canal beyondthe field of vision from the vagina.


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Human papilloma virus (HPV)

! Over 20 serotypes

! Cause a variety of lesions with the differentserotypes associated with different lesions.

Mild dysplasiais usually caused by "low risk"

HPV serotypes, 6 and 11

High- grade dysplasiais caused by "high (16and 18) and moderate (31,33,35) risk" HPV

serotypes


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Normal


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Koilocytes(visibly HPV-infected cells) Notice the binucleate one with the big halo.


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Dysplasia, severe.The less cytoplasm, the more severe the dysplasia.


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Normal


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Border between normal and severe dysplasia.Most conspicuous is the high N/C ratio

and the loss of the normal maturation.


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List of terms that confused me

! Neoplasia = process of new growth

! Metaplasia = one adult cell type replacesanother adult cell type. It may represent anadaptation of one cell type to another celltype that is more likely to survive in theenvironment

! Dysplasia = disordered growth

! Anaplasia = undifferentiated cell growth(malignant!)


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Normal cervical squamous epithelium (left) Dysplastic on the right.


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kristyn feldman histology.pdf

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