Ultrastructural observation of human papillomavirus particles in the uterine cervix intraepithelial neoplasia

: Using transmission electron microscopy (TEM), twenty two cases of an intraepithelial lesion in the uterine cervix have been examined for the presence of human papillomavirus (HPV) particles. In 21 of these cases (95%), HPV particles were detected in the nucleus, and in 5 cases, in the cytoplasm. The distribution of the intranuclear HPV particles was classified into 4 types. In only 2 cases did the exhibited particles show a geometrical crystalline array (type I). In most cases, the exhibited particles were either seen to show an aggregate non-crystalline array (type II) or were concentrated around the chromatin (type III). Some cases also were found to show particles that were scattered sporadically in the nucleoplasm (type IV).