This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Gynaecology & Obstetrics
[{'content': 'Koilocytes with dyskeratosis and perinuclear halo on pap smear is pathognomonic of which of the following? \nSelect and explain. \nA. HPV infection, B. Metaplasia, C. Dysplasia, D. Bacterial vaginosis', 'role': 'user'}, {'content': 'Answer: A \nExplanation: The presence of abnormal koilocytes (keratinocytes with pyknotic, deeply blue nuclei surrounded by a halo and clear cytoplasm with a paucity of keratohyaline granules), or koilocytosis, is a characteristic feature of productive HPV infection. Other cytologic markers of HPV infection include acanthosis, dyskeratosis, and multinucleation. Virus multiplication is confined to the host cell nucleus. Consequently, infected cells exhibit a high degree of nuclear atypia.', 'role': 'assistant'}]