Cervical Pathology — Dysplasia and Carcinoma

HPV Molecular Oncogenesis

• Persistent HPV infection (particularly types 16 and 18) is the necessary initiating event; high-risk HPV types express viral oncoproteins E6 and E7
• E6 protein binds and inactivates p53 tumor suppressor through proteasomal degradation, eliminating apoptosis and cell cycle checkpoints
• E7 protein targets retinoblastoma (Rb) protein, releasing E2F transcription factors and driving uncontrolled S-phase entry
• Loss of p53 and Rb functions prevents DNA damage-induced apoptosis and allows accumulation of secondary mutations
• Viral DNA typically integrates into the host genome during progression to invasive cancer, disrupting the E2/E4 open reading frame and increasing E6/E7 expression

Cervical Epithelial Transformation

• Normal cervical epithelium: stratified squamous epithelium with well-organized basal, parabasal, intermediate, and superficial layers; high nuclear-to-cytoplasmic (N:C) ratio limited to basal layer only
• CIN I (Low-Grade Dysplasia): nuclear abnormalities (hyperchromasia, coarse chromatin, irregular membranes) confined to basal and parabasal third of epithelium; preserved maturation and surface keratinization
• CIN II (Intermediate-Grade): dysplasia extends to middle third of epithelium; increased mitotic activity including abnormal figures; reduced cytoplasmic differentiation
• CIN III (High-Grade Dysplasia/Carcinoma In Situ): dysplasia involves two-thirds to full thickness of epithelium; abundant mitotic figures; marked nuclear pleomorphism; loss of normal maturation
• Invasion: occurs when neoplastic cells breach the basement membrane and infiltrate underlying stroma; associated with loss of E-cadherin and epithelial-mesenchymal transition (EMT)

Field Effect and Multifocality

• HPV infection may involve the entire transformation zone, creating field of risk predisposing to multicentric lesions
• Regression occurs in ~90% of low-grade lesions but in <10% of high-grade lesions; persistence correlates with viral load and host immune status

Major Causative Agent

• Persistent HPV infection (necessary but not sufficient alone); high-risk types include HPV-16 (50–60% of SCC), HPV-18 (10–15%), and types 31, 33, 35, 39, 45, 51, 52, 56, 58, 59
• HPV transmission occurs through sexual contact; risk increases with number of sexual partners, early age of first intercourse, and partner with HPV exposure

Patient-Related Risk Factors

• Immunosuppression (HIV/AIDS with CD4 <200, organ transplant): 25–40-fold increased risk due to impaired clearance of HPV
• Smoking: 2–3-fold increased risk; tobacco carcinogens (nitrosamines, benzo[a]pyrene) act synergistically with HPV; smoking impairs local immunity
• Long-term oral contraceptive use (>5 years): 1.5–2-fold relative risk; proposed mechanisms include hormonal effects on epithelium and increased cervical ectopy
• Multiparity (≥3 pregnancies): increased cervical trauma and inflammation; may reflect cumulative HPV exposure
• Young age at first pregnancy (<17 years): cervix more susceptible to malignant transformation
• Poor cervical screening or lack of access to preventive healthcare
• Previous abnormal Pap smear or history of dysplasia
• Other sexually transmitted infections (HSV, chlamydia, gonorrhea): may increase inflammation or act as cofactors

Protective Factors

• HPV vaccination (quadrivalent or nonavalent): 90%+ efficacy if given before sexual debut; provides cross-protection against related types
• Barrier contraception (condoms): reduces HPV transmission
• Early and complete treatment of precancerous lesions

Asymptomatic (Dysplasia)

• Most dysplastic lesions (CIN I–III) are asymptomatic and detected only through screening
• Cervical dysplasia confined to epithelium produces no symptoms because it does not breach the basement membrane
• Patient may report only incidental abnormal Pap smear result

Preinvasive Disease With Symptoms

• Abnormal vaginal bleeding (intermenstrual bleeding, postcoital bleeding, postmenopausal bleeding): occurs with early stromal invasion or friable lesions
• Abnormal vaginal discharge: may be blood-stained, purulent, or mucinous; reflects tissue necrosis or infection of ulcerated lesion
• Cervical lesion on visual inspection: may appear as friable, ulcerated, or polypoid mass, though some dysplastic lesions are not grossly visible

Invasive Cervical Cancer (Advanced)

• Vaginal bleeding and blood-stained discharge: cardinal symptom of invasive disease; results from friability and ulceration of tumor
• Pelvic and lower back pain: indicates parametrial invasion, pelvic sidewall involvement, or nerve invasion
• Urinary symptoms (dysuria, frequency, hematuria): from invasion of bladder trigone or urethra; may progress to urinary obstruction
• Fecal symptoms (rectal bleeding, constipation): from posterior involvement of rectosigmoid
• Vaginal fistula (ureterovaginal, rectovaginal): results from advanced invasive disease with necrosis
• Lower extremity edema and lymphedema: from lymph node involvement and lymphatic obstruction
• Systemic symptoms in advanced disease: weight loss, anorexia, cachexia (from advanced metastatic disease)

Physical Examination Findings

• Cervical visualization: dysplasia may not be visible; invasive carcinoma typically presents as ulcerated, friable, exophytic, or polypoid cervical mass
• Vaginal speculum findings: abnormal bleeding, lesion grossly apparent, cervical distortion
• Bimanual pelvic exam: uterine fixation (parametrial invasion), palpable parametrial induration, nodularity of uterosacral ligaments
• Lymph node examination: supraclavicular, inguinal, and pelvic node enlargement (metastatic disease)

Correlation With Morphology

• Dysplasia is endocervical or ectocervical epithelial abnormality without stromal invasion → typically not visible and asymptomatic
• Invasive carcinoma breaches basement membrane with infiltration into cervical stroma → friable, ulcerated, bleeding appearance

Screening Cytology (Pap Test) and Triage

• Conventional Pap smear or liquid-based cytology (ThinPrep, SurePath): standard screening method; cells obtained from cervicovaginal junction using spatula and endocervical brush
• Atypical squamous cells of undetermined significance (ASCUS): borderline cytologic changes; management includes HPV testing (reflex testing) or repeat cytology; HPV-positive ASCUS requires colposcopy
• Low-grade squamous intraepithelial lesion (LSIL): consistent with CIN I; may reflect HPV infection; approximately 30–40% progress to high-grade lesions; management typically includes HPV testing (if not already known) or repeat cytology; colposcopy if HPV-positive or persistent cytologic abnormality
• High-grade squamous intraepithelial lesion (HSIL): consistent with CIN II–III or early invasion; ~60–70% harbor CIN II/III; requires immediate colposcopy with biopsy
• Atypical glandular cells or adenocarcinoma cells: rare; warrant colposcopy and endometrial evaluation

HPV Testing

• High-risk HPV DNA testing (molecular PCR or hybrid capture): detects presence of high-risk types; positive in ~90% of dysplastic lesions
• HPV typing: identifies specific type (HPV-16, HPV-18, others); HPV-16/18 associated with higher risk of progression and invasion
• Used for triage of ASCUS and posttreatment surveillance
• Negative HPV test in setting of cytologic abnormality generally indicates lower risk (except in immunocompromised patients)

Colposcopy and Biopsy

• Direct visualization of cervix under magnification (typically 10–15×) with 3% acetic acid (whitens dysplastic epithelium) and Lugol's iodine (normal glycogen-rich epithelium stains brown; dysplasia does not)
• Colposcopic findings:
• Acetowhite epithelium: white epithelium after acetic acid application; indicates increased nuclear density and abnormal vasculature; classified as low-grade or high-grade based on intensity and sharpness of borders
• Abnormal vasculature: punctation (dots of blood vessels on surface; low-grade) or mosaicism (irregular vessel pattern; high-grade)
• Lesion margins: sharp demarcation suggests high-grade lesion; indistinct margins more consistent with low-grade or normal variation
• Directed tissue biopsy to specific acetowhite areas: gold standard for diagnosis of dysplasia when colposcopic abnormality identified
• Endocervical curettage (ECC): samples upper endocervical canal to exclude occult high-grade dysplasia; indicated if transformation zone not fully visualized

Histopathological Examination (Gold Standard)

Cervical Intraepithelial Neoplasia I (Low-Grade Dysplasia)

• Nuclear enlargement limited to basal and parabasal layers; nuclei 6–8× diameter of superficial cell nucleus
• Koilocytic changes (characteristic finding): mature superficial cells with large nuclear halos, wrinkled nuclear membranes, hyperchromatic nuclei—reflects productive HPV infection
• Preserved stratification and maturation toward surface; superficial keratinization intact
• Mitotic figures present but predominantly in lower layers
• Intact basement membrane

Cervical Intraepithelial Neoplasia II (Intermediate-Grade Dysplasia)

• Nuclear abnormalities extend to middle third of epithelium
• Loss of maturation more apparent; reduced cytoplasmic volume in superficial cells
• Increased mitotic activity including abnormal mitotic figures; mitoses present at all levels
• Koilocytic changes less prominent than CIN I; productive HPV infection decreasing
• Basement membrane intact

Cervical Intraepithelial Neoplasia III (High-Grade Dysplasia/Carcinoma In Situ)

• Full-thickness or near-full-thickness dysplasia: nuclear abnormalities involve two-thirds to entire epithelial thickness
• Marked nuclear pleomorphism: variation in size (anisokaryosis), shape (irregular contours), and staining (hyperchromatic nuclei)
• Abundant mitotic figures at all levels including surface; many abnormal mitoses (tripolar, quadripolar)
• Minimal cytoplasmic differentiation; cells appear immature throughout
• Coarse, clumped chromatin with irregular nuclear membranes
• Intact basement membrane (by definition, invasion has not occurred)
• Absence of koilocytic changes (indicates nonproductive infection and progression)

Invasive Squamous Cell Carcinoma

• Infiltration of neoplastic cells through and beyond basement membrane into underlying cervical stroma
• Nests, cords, or islands of dysplastic squamous epithelium invading stroma
• Desmoplastic stromal response: dense fibrous tissue surrounding malignant nests (indicates host response to invasion)
• Nuclear pleomorphism, coarse chromatin, prominent nucleoli
• Abundant mitotic figures including abnormal forms
• Varying degrees of differentiation:
• Well-differentiated (keratinizing): abundant keratin production, pearl formation, prominent intercellular bridges
• Moderately differentiated: less keratinization, more nuclear pleomorphism
• Poorly differentiated: marked nuclear pleomorphism, minimal keratinization, high mitotic rate, extensive necrosis
• Tumor necrosis (particularly in large lesions)
• Depth of invasion and lymph-vascular space invasion (LVSI) assessed: negative LVSI favorable prognostic indicator

• Mucinous, endometrioid, or clear cell histology
• Glandular structures invading stroma; may show mucin production
• Often more difficult to detect on cytology and may present at advanced stage
• HPV-18 association stronger than with squamous carcinoma

Gross Pathology

• Dysplasia: typically not visible on gross inspection; may appear as subtle epithelial thickening
• Invasive carcinoma: ulcerated, friable, exophytic or endophytic lesion on cervix; tan-white to gray cut surface reflecting areas of necrosis and fibrosis; lesion may distort cervical anatomy; may extend into cervical canal (endocervical disease) or vagina

Laboratory and Imaging Studies

• Complete blood count (CBC): anemia if chronic vaginal bleeding
• Comprehensive metabolic panel: renal dysfunction if ureteral obstruction
• Pelvic ultrasound or MRI: initial imaging for suspected invasive disease; assesses tumor size, cervical stromal invasion, parametrial involvement, pelvic sidewall invasion
• Chest X-ray or CT chest/abdomen/pelvis: to exclude distant metastases in advanced disease
• PET-CT: may be used for staging high-grade cancers to detect metastatic disease
• Cystoscopy/proctoscopy: if invasion of bladder or rectum suspected

Diagnostic Criteria and Staging

• Diagnosis of dysplasia requires colposcopic biopsy showing CIN I, II, or III
• Invasive carcinoma diagnosed on biopsy showing tumor infiltrating beyond basement membrane
• TNM staging (FIGO staging for cervical cancer):
• Stage IA: microscopic invasion ≤5 mm depth, ≤7 mm horizontal spread (diagnosed on cone specimen, not on simple biopsy)
• Stage IB: clinical or gross lesion confined to cervix, or >5 mm depth invasion
• Stage II: tumor extends beyond cervix but not to pelvic sidewall or lower third vagina
• Stage III: extends to pelvic sidewall and/or lower third vagina and/or causes hydronephrosis
• Stage IV: invades bladder/rectum mucosa (IVA) or distant metastases (IVB)

Precancerous Lesions (CIN I, II, III)

CIN I (Low-Grade Dysplasia)

• Observation with repeated cytology/HPV testing: given high spontaneous regression rate (~90%); acceptable if adequate follow-up assured
• Excisional procedure (loop electrosurgical excision procedure [LEEP], cold knife conization, or laser conization): may be used if patient preference or concern for occult high-grade disease

Complications of untreated invasive disease

• Bilateral ureteral obstruction → obstructive uropathy: parametrial tumor encases the ureters as they pass under the uterine arteries ("water under the bridge"); signals itself as hydronephrosis on imaging with rising creatinine and hyperkalemia. Uremia from obstruction is the classic cause of death in advanced cervical cancer. Emergency — anuria, refractory hyperkalemia, or infected obstruction (pyonephrosis/urosepsis) requires urgent percutaneous nephrostomy or ureteral stenting.
• Massive vaginal hemorrhage: friable, necrotic exophytic tumor erodes cervical branches of the uterine artery. Presents as brisk bleeding with hemodynamic instability. Emergency — vaginal packing, tranexamic acid, hemostatic radiation, or arterial embolization.
• Fistula formation (vesicovaginal, rectovaginal, ureterovaginal): full-thickness tumor necrosis into adjacent viscera; signaled by continuous watery vaginal leakage or passage of stool/gas per vagina.
• Lymphatic obstruction and venous thromboembolism: pelvic nodal metastasis causes unilateral lower-extremity lymphedema; malignancy plus pelvic compression yields DVT/PE. Emergency if pleuritic chest pain and hypoxemia develop.
• Sciatic-distribution pain and hydronephrosis together indicate pelvic sidewall (FIGO III) disease.

Complications of treatment

• Excisional procedures (LEEP, cold-knife cone): removal of cervical stroma causes cervical insufficiency and cervical stenosis. ACOG notes an increased risk of preterm birth and PPROM after conization, greatest with deeper/repeat excisions; stenosis presents as hematometra, dysmenorrhea, or an unsatisfactory future Pap. Delayed post-LEEP bleeding typically occurs about a week out as the eschar sloughs.
• Radical hysterectomy: ureteral injury/fistula, bladder atony from injury to inferior hypogastric plexus fibers (urinary retention), and lymphocele after lymphadenectomy.
• Chemoradiation (per NCCN cervical cancer guidelines, cisplatin-based): acute radiation proctitis/cystitis, chronic radiation enteritis with strictures, vaginal stenosis and dyspareunia, premature ovarian failure, and rare radiation-associated second malignancy. Cisplatin adds nephrotoxicity, ototoxicity, and peripheral neuropathy.
• Bevacizumab (added for recurrent/metastatic disease): impaired VEGF-dependent mucosal healing causes hypertension, thrombosis, and GI perforation/fistula — a surgical emergency heralded by acute abdomen or feculent vaginal discharge.

• The lesion always arises at the transformation zone: the squamocolumnar junction, where endocervical columnar epithelium undergoes metaplasia to squamous epithelium. Actively metaplastic basal cells are the HPV target — this is why sampling must include the endocervical canal and why an inadequately sampled or non-visualized transformation zone mandates endocervical curettage.
• Koilocytes are the buzzword for productive HPV infection, not for cancer: perinuclear halo, wrinkled "raisinoid" nucleus. They are most prominent in CIN I/LSIL and disappear as lesions progress to CIN III, because integrated virus no longer completes its productive cycle.
• E6 → p53 degradation; E7 → Rb inactivation. A stem describing "viral protein promotes ubiquitin-mediated degradation of p53" is E6. Diffuse block-positive p16 immunostaining is the surrogate marker of high-grade disease: Rb inactivation by E7 releases E2F and drives compensatory p16 overexpression.
• HPV 16 dominates squamous cell carcinoma; HPV 18 is disproportionately linked to adenocarcinoma, which is harder to detect cytologically and more often presents at higher stage. HPV 6 and 11 cause condyloma acuminatum and are the classic distractor — low-risk, non-oncogenic.
• Single best next step for HSIL cytology is colposcopy with directed biopsy (ASCCP 2019 risk-based guidelines; expedited excision is an option for nonpregnant patients age 25 and older). Do not repeat the Pap, and do not proceed to hysterectomy on cytology alone.
• Screening starts at age 21 regardless of age of sexual debut or vaccination status (USPSTF; ACS supports primary HPV testing beginning at 25). Vaccinated patients still require screening — a frequent stem trap.
• Postcoital or intermenstrual bleeding in a young woman requires speculum examination and biopsy of any visible lesion, not reassurance and not a Pap alone — cytology can be falsely negative with frank invasive tumor.
• DES-associated clear cell adenocarcinoma of the vagina/cervix is HPV-independent and is the classic distractor when the stem mentions in-utero exposure.