A routine Pap smear on a 27-year-old woman is reported as a low-grade squamous intraepithelial lesion with prominent koilocytosis. Which of the following is the most likely etiology for this finding?
(A) hereditary disorder of squamous epithelium
(B) hormonal imbalance
© human papillomavirus
(D) normal intermenstrual reaction
(E) protozoan infection or infestation
©Asignificant proportion of low-grade squamous intraepithelial lesions result from human papillomavirus infection. Viral subtypes 16 and 18 are more likely to progress to highgrade dysplasias. Koilocytosis is the usual morphologic marker of viral infection. It is unlikely that these changes would result from a hereditary disorder (choice A), hormonal imbalances (choice B), normal intermenstrual reactions (choice D), or a protozoan infection (choice E).