The clinical and histologic picture of 84 anogenital condylomatous and condyloma-like lesions of both sexes were analyzed in an effort to establish a correlation to the different papillomavirus (PV) types. The presence of human papillomavirus (HPV)-specific DNA sequences was confirmed through molecular hybridization and the presence of PV structure antigens was verified in thin sections by means of a group-specific anti-PV-antiserum using the peroxidase-antiperoxidase (PAP) technique. Three distinct clinical forms harboring distinct HPV types were distinguished: (1) Condylomata acuminata in which HPV-6 DNA was present in 37 of 59 samples and HPV-11 DNA in only 13 of 59 samples. HPV-16 DNA was not detected at all and 9 condylomatous lesions remained unclassified. (2) Flat condyloma-like lesions, where HPV-6 and HPV-11 were associated with lesions of low epidermal atypia in 8 and in 2 of 18 cases, respectively, and where HPV-16 was associated exclusively with 6 of 18 such lesions with severe atypia, called bowenoid papulosis. (3) Pigmented papules where HPV-16 was detected twice in lesions of bowenoid papulosis and HPV-11 in 2 of the benign pigmented lesions. The fourth clinical manifestation of genital papillomavirus infections--the so-called condylomata plana--was not available for virologic analysis. Histologically 5 different koilocytotic features were determined which could not be correlated either with one of the clinical pictures or with a specific PV type. HPV-16, however, was found frequently in non-koilocytotic lesions exhibiting the features of severe epithelial atypia known in bowenoid papulosis. The existence of PV structure antigens in these lesions could not be verified using the indirect immunoperoxidase--PAP-technique--in contrast to the koilocytotic lesions where clear evidence of the presence of HPV was proved in 36 of 56 (64.3%) of the cases.