On Pap smear, which cytological finding is MOST specific for high-grade cervical intraepithelial neoplasia (CIN 3)?
- A Koilocytes with perinuclear clearing and binucleation restricted to the surface layers
- B Cells with scant cytoplasm, high nuclear-to-cytoplasmic ratio, irregular hyperchromatic nuclei, and nuclear membrane irregularity extending to the basal one-third of the epithelium ✓
- C Endocervical cells with mucin vacuoles and picket-fence arrangement
- D Navicular cells with glycogen-rich cytoplasm and eccentric nuclei
Correct answer: B. Cells with scant cytoplasm, high nuclear-to-cytoplasmic ratio, irregular hyperchromatic nuclei, and nuclear membrane irregularity extending to the basal one-third of the epithelium
Explanation
CIN 3 (high-grade SIL) shows full-thickness or near-full-thickness replacement of squamous epithelium by dysplastic cells with high N:C ratio, marked nuclear hyperchromasia, and irregular nuclear membranes; these abnormal cells extend to the basal third or beyond. Koilocytes (perinuclear halos, binucleation) indicate HPV cytopathic effect and are associated with low-grade CIN 1. Navicular cells are pregnancy-associated normal variants.
Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.