Cervical Pathology and Neoplasia

Cervical Anatomy & Histology - Neck of the Matter

• Cervix: Lower, narrow part of uterus opening into vagina.
  • Ectocervix: Projects into vagina; lined by stratified squamous non-keratinized epithelium.
  • Endocervix (canal): Lined by simple columnar (mucinous) epithelium.
• Key Junctions:
  • Squamocolumnar Junction (SCJ): Original meeting point of squamous and columnar epithelia.
  • Transformation Zone (TZ): Area between original and new SCJ; undergoes squamous metaplasia.

    ⭐ The transformation zone (TZ) is the primary site for development of cervical intraepithelial neoplasia and cervical cancer.

Cervicitis & Benign Lesions - Inflamed Gateway

• Cervicitis: Inflammation of cervix; acute (neutrophils; e.g., Chlamydia, Gonorrhea) or chronic (lymphocytes, plasma cells).
  • Symptoms: Discharge, postcoital bleeding.
• Benign Lesions:
  • Endocervical Polyps: Common; may cause bleeding.
  • Microglandular Hyperplasia: OCP/pregnancy-linked.

⭐ Nabothian cysts are common benign findings, resulting from blocked endocervical glands.

CIN & SIL - Dysplasia Drama

Cervical Intraepithelial Neoplasia (CIN) and Squamous Intraepithelial Lesion (SIL) are spectra of pre-invasive cervical disease. Caused mainly by persistent high-risk HPV (types 16, 18). CIN grading (1, 2, 3) reflects dysplasia severity; Bethesda system (LSIL, HSIL) guides management. $p16^{INK4a}$ overexpression is a key HSIL marker.

Management depends on grade: observation for LSIL, treatment (e.g., LEEP) for HSIL to prevent progression.

⭐ HSIL (CIN 2/3) encompasses lesions with a high risk of progression to invasive carcinoma and requires management.

HPV & Carcinogenesis - Viral Villains

Human Papillomavirus (HPV), a DNA virus, is the main etiological agent.

• Types:
  • High-Risk (HR-HPV): 16, 18, 31, 33, 45 (oncogenic).
  • Low-Risk (LR-HPV): 6, 11 (condylomas).
• Oncogenic Proteins (HR-HPV):
  • E6: Degrades p53 (tumor suppressor) → ↓apoptosis.
  • E7: Inactivates Rb (tumor suppressor) → releases E2F → ↑cell proliferation.
• Mechanism:

⭐ High-risk HPV types 16 and 18 account for over 70% of cervical cancers worldwide.

• Key Risk Factors: Multiple sexual partners, early coitarche, immunosuppression (e.g., HIV), smoking.

Invasive Cervical Cancer - Malignant March

⭐ Squamous cell carcinoma is the most common histological type of invasive cervical cancer.

• Types & Characteristics:

  Feature	Squamous Cell Ca (SCC)	Adenocarcinoma
  Epidemiology	Most common type; HPV 16, 18	↑ incidence; Younger; HPV 18 > 16
  Morphology	Nests/sheets of squamous cells, keratin pearls, intercellular bridges	Glandular differentiation, mucin production
  Markers	p63+, CK5/6+, p40+	CEA+, CA-125+, p16+, HIK1083

• FIGO Staging: Crucial for management. Stage I: Cervix only. II: Beyond cervix (not to pelvic wall/lower ⅓ vagina). III: Extends to pelvic wall/lower ⅓ vagina/hydronephrosis. IV: Invades bladder/rectum or distant metastasis.

Screening & Prevention - Guarding the Gate

• Screening Tests: Pap smear (cytology), high-risk HPV (hrHPV) DNA testing, Co-testing (Pap + hrHPV).
• Key Guidelines: Pap q3yrs (21-29y); hrHPV or Co-test q5yrs (30-65y).
• Primary Prevention: HPV vaccination (e.g., Gardasil 9) protects against oncogenic HPV types.

⭐ The Bethesda System is the standard for reporting cervical cytology (Pap smear) results.

High‑Yield Points - ⚡ Biggest Takeaways

• High-risk HPV (16, 18) causes most CIN and cervical cancer.
• Koilocytes (halo, wrinkled nucleus) signify HPV infection.
• LSIL (CIN I) often regresses; HSIL (CIN II/III) has higher progression risk to invasive cancer.
• p16INK4a overexpression is a key biomarker for HSIL.
• Most cervical cancers arise in the transformation zone.
• Squamous cell carcinoma is the most common type.
• Pap smear and HPV DNA testing are vital for screening.