Summary
Cervical Intraepithelial Neoplasia (CIN) is a precancerous cervical lesion graded I–III based on severity. It may regress or progress to cancer, especially in higher grades. Screening with Pap smears and HPV testing detects early changes. Management includes observation, excision, or ablation, depending on grade and persistence.
Definition
Characterized by epithelial dysplasia that begins at the basal layer of the squamocolumnar junction and extends outward.
Grading
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CIN I: Mild dysplasia (lower 1/3)
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CIN II: Moderate (lower 2/3)
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CIN III:
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Severe dysplasia (≥2/3)
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CIS: Full-thickness dysplasia without invasion
Natural History
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CIN I: 15% progress
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CIN II: 25%
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CIN III: 50%
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May also regress or remain static
Screening (Pap Smear/Cytology)
When to Start
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<21 years: No screening, regardless of sexual activity
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21–29 years: Cytology every 3 years
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30–65 years:
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Cytology every 3 years, OR
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Co-testing with HPV every 5 years
When to Stop
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After 65 years if 3 consecutive negative tests in past 10 years
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After total hysterectomy for benign disease with no CIN history
Pap Collection
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Samples from transformation zone (TZ) and endocervical canal
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TZ is the site of 95% of dysplastic changes
Cytology Classification (Bethesda System)
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Negative
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ASC-US: Atypical squamous cells of undetermined significance
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LSIL: Low-grade (CIN I)
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ASC-H: Cannot exclude HSIL
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HSIL: High-grade (CIN II/III or CIS)
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Squamous cell carcinoma
Management of Abnormal Pap Results
ASC-US/LSIL (Age 21–24)
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Repeat cytology in 12 months
ASC-US (≥25 years)
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Prefer HPV DNA testing
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If high-risk HPV positive → Colposcopy
LSIL/ASC-H/HSIL
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Colposcopy and biopsy
If Colposcopy is Unsatisfactory
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Consider Endocervical Curettage (ECC) or Cone Biopsy
CIN Treatment
CIN I
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Observation preferred
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If persistent >2 years → Excision (LEEP/LLETZ) or Cryotherapy
CIN II/III
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Excisional treatments:
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LEEP, Cold Knife Conization (CKC)
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Ablative methods (laser, cryo) in some cases
Recurrent CIN 2/3
- Total hysterectomy may be considered
Complications of Conization
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Cervical stenosis
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Incompetent cervix
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Infertility
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Preterm labor
احصل على التجربة الكاملة
اشترك للوصول لفيديوهات الشرح التفصيلي والبطاقات التعليمية التفاعلية وأسئلة الممارسة مع تتبع التقدم.