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Pre-Cancerous Epithelial Changes: Cervical Intraepithelial Neoplasia (CIN)

Cervical Intraepithelial Neoplasia (CIN) refers to pre-cancerous epithelial changes in the cervix that have the potential to progress to cervical cancer if left untreated. CIN is classified into three grades (CIN I-III) based on the level of dysplasia and proportion of the epithelial layer involved. Lower grades (CIN I) involve the lower third of the epithelium and mild dysplasia, while higher grades (CIN III) involve the upper two-thirds and more severe dysplasia. Known risk factors for developing CIN include early sexual activity, multiple sexual partners, HPV infection, smoking, and lower socioeconomic status. Over time dysplastic cells can become more

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38 views4 pages

Pre-Cancerous Epithelial Changes: Cervical Intraepithelial Neoplasia (CIN)

Cervical Intraepithelial Neoplasia (CIN) refers to pre-cancerous epithelial changes in the cervix that have the potential to progress to cervical cancer if left untreated. CIN is classified into three grades (CIN I-III) based on the level of dysplasia and proportion of the epithelial layer involved. Lower grades (CIN I) involve the lower third of the epithelium and mild dysplasia, while higher grades (CIN III) involve the upper two-thirds and more severe dysplasia. Known risk factors for developing CIN include early sexual activity, multiple sexual partners, HPV infection, smoking, and lower socioeconomic status. Over time dysplastic cells can become more

Uploaded by

Siti Aisyah
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© © All Rights Reserved
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Pre-cancerous epithelial changes : Cervical Intraepithelial Neoplasia

(CIN)

 Pre-cancerous condition is a pathological processes that tend eventually to become


malignant. (Dorland)
 Pre-invasive cancer / precancerous condition  recognized that epithelial changes
could be identified that had the appearance of invasive cancer but were confined to the
epithelium.
 Subsequent studies showed that if these lesions are not treated, they can progress to
cervical cancer.
 CIN
 Early precursor lessions called dysplasia (abnormal maturation), which signaled
possible development of future cancer.
 Proliferating metaplasia without mitotic activity should not be called dysplasia.
 Squamous metaplasia should not be diagnosed as dysplasia (or CIN) because it does not
progress to invasive cancer.
 In most cases, CIN is believed to originate as single focus in the transformation zone at
the advancing squamocolumnar junction.
 The anterior lip of the cervix is twice as likely to develop CIN as the posterior lip, and
CIN rarely originaes in the lateral angles.
 The only way to determine where the original SCJ was located is to look for nabothian
cysts (created when mucus-secreting columnar cells are covered by the metaplastic
squamous epithelium).
 Once the metaplastic epithelium matures and forms glycogen, it is called the healed
transformation zone and is relatively resistant to oncogenic stimuli.
 CIN is most likely to begin either during menarche or after pregnancy, when
metaplasia is most active.
 Conversely, after menopause a woman undergoes little metaplasia and is at lower risk
of developing CIN
 Precancerous changes usually take many years, perhaps decade to evolve into overt
carcinomas.
 Important risk factors for the development of CIN and invasive carcinoma :
- Early age at first intercourse
- Multiple sexual partners
- A male partner with multiple previous sexual partners
- Persistent infection by “high-risk” HPV
- Location of HPV infection in transformation zone
- Exogenous or endogenous immunodeficiency
- The higher incidence in lower socioeconomic groups
- The rarity among virgins
- The association with multiple pregnancies
- Cigarette smoking

Classification of CIN

 Criteria for the diagnosis may vary according to :


- Cellular immaturity
- Cellular disorganization
- Nuclear abnormalities
- Increased mitotic activity
 Classification :

1. CIN I :
- Lower one third
of the epithelium
- Mild dysplasia
- Flat condyloma
(genital warts)
- Koilocytotic
changes mostly in the superficial layers of the epithelium
- Koilocytosis  hyperchromasia (elevated chromatin, nuclei become very dark) ;
nuclei become enlarged ; nuclei is surrounded by halos or rings

2. CIN II :
- Middle third of epithelium
- Dysplasia is more severe / moderate dysplasia
- Associated with some variation in cell and nuclear size
- Heterogeneity of nuclear chromatin
- Mitoses above the basal layer extending in to the middle third of the epithelium
- Superficial layer of cells shows some differentiation, and in some cases it shows the
koilocytotic changes.
3. CIN III
- Upper third of epithelium
- Severe dysplasia
- Even greater variation in cell and nuclear size
- Chromatin heterogeneity
- Disorderly orientation of the cells
- Normal and abnormal mitoses
- These changes affect virtually all layers of the epithelium and are characterized by
loss of maturation
- Differentiation of surface cells and koilocytotic changes have usually disappeared
 CIN may begin as low-grade CIN and progress to higher grade CIN, or they may begin at
the outset as high-grade CIN.
 In time, dysplastic become more atypical, and may extend into the endocervical glands,
but the alterations are confined to the epithelial layer and its glands, these changes
constitue carcinoma in situ.
 The next stage, if it is to appear, is invasive cancer.

Source : Robbin + Berek&Novak

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