A 28-year-old nulliparous woman undergoes routine cervical cancer screening in an urban health centre. Her liquid-based cytology (LBC) shows atypical squamous cells, cannot exclude high-grade squamous intraepithelial lesion (ASC-H). She is HPV-16 positive on reflex testing. What is the most appropriate next step in management?

## Cytological Category: ASC-H **Key Point:** ASC-H (atypical squamous cells, cannot exclude high-grade SIL) is a high-risk cytological category with ~24–50% risk of underlying CIN 2/3 or cancer. It is distinct from ASCUS and carries much higher suspicion for significant pathology. ## Risk Stratification by HPV Status | Cytology | HPV-Positive | HPV-Negative | | --- | --- | --- | | ASCUS | Colposcopy | Repeat cytology in 12 months | | ASC-H | **Colposcopy** (regardless of HPV) | **Colposcopy** (regardless of HPV) | | LSIL | Colposcopy or HPV reflex | Repeat cytology in 12 months | | HSIL | Colposcopy | Colposcopy | **High-Yield:** ASC-H is a **mandatory colposcopy** category. HPV positivity in an ASC-H patient further reinforces the need for immediate colposcopy, as HPV-16 (high-risk type) is strongly associated with CIN 2/3 and cancer. ## Why Colposcopy Is the Next Step 1. ASC-H cytology alone warrants colposcopy (high risk of CIN 2/3) 2. HPV-16 positivity adds significant oncogenic risk 3. Direct visualization and tissue diagnosis are needed to exclude high-grade disease 4. Colposcopy allows assessment of lesion grade and guides treatment decisions **Clinical Pearl:** HPV-16 and HPV-18 are oncogenic types responsible for ~70% of cervical cancers. Detection of HPV-16 in the setting of ASC-H or HSIL is a strong indicator for colposcopy and biopsy. **Mnemonic:** **ASC-H = Always Send to Colposcopy** — this category has too high a risk of underlying CIN 2/3 to defer. [cite:ASCCP 2019 Guidelines; Robbins 10e Ch 22]