Origin of the koilocyte in condylomata of the human cervix: ultrastructural study

Twelve biopsies from condylomatous lesions of the human cervix were examined by transmission electron microscopy in order to study koilocytotic cells. The ultrastructure of koilocytes, revealed mainly cytoplasmic changes in the perinuclear area. These changes first appeared in cells of the intermediate layers and extended to the surface of the epithelium. The cells involved showed small perinuclear areas, with a fine granular material, which appeared as a lysis of the cytoplasmic matrix, forming microvacuolelike structures that gradually enlarged and fused together, ending with the formation of a large clear zone (koliocytosis). Binucleation and polylobulation were constant features. Intranuclear virus particles were often associated with koilocytes. Tubules and large bundles or single filamentous structures were also observed in koilocytes detected in smears and biopsies. This study provides further evidence that the koilocytes is the result of a process characterized by cellular changes due to cytopathogenic effect of the human papillomavirus.