February 21, 2022 Case of the Week

Young woman, routine Pap smear.
What are these cells? What caused these changes? Dx?

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Answer:
koilocytes: mature squamous cells with HPV cytopathic changes(≥1 hyperchromatic enlarged nuclei, surrounded by perinuclear halo, thick cytoplasmic rim). Low grade squamous intraepithelial lesion (LSIL).