Histopathological alterations of condylomata acuminata were characterized by hyperkeratosis, parakeratosis, acanthosis, elongation of the rete ridges, pseudoepitheliomatous hyperplasia, discrete or grouped koilocytes, proliferation and dilatation of dermal capillaries, lymphocytic and histocytic infiltration around dermal capillaries. Histopathological pattern of pseudocondyloma of vulvae were characterized by finger-shaped configuration, epithelium was similar to normal of mucous membrane without atypia. The lesion was composed of a rich vascular network surrounded by connective tissue and a mild lymphocytic infiltration. Ultrastructural alterations of condylomata acuminata were characterized by proliferation of basal cells, enlarged and swollen nuclei in all layers, 1-4 large nucleoli, 1-3 nuclear bodies, interchromatin granules and perichromatin granules in some proliferating nuclei, swollen mitochondria, dilated endoplasmic reticulum, and dissolved glycogen. Ultrastructural alterations of pseudocondyloma of vulvae were characterized by proliferation of mucomembranous epithelial cells, mild swollen nuclei, 1-2 nucleoli, no nuclear body interchromatin and perichromatin granule, the dilatation of interstitial capillaries, and abundant fibril bundles in the dermis. Thus, the histopathological and ultrastructural manifestations of condylomata acuminata and pseudocondyloma of vulvae were significantly different. It may be of help in differentiation between the two disease.