Detection of human papillomavirus DNA in keratoacanthomas by polymerase chain reaction

The etiology of keratoacanthomas is unknown, but human papillomavirus (HPV) has been suspected to be involved in the pathogenesis of this lesion because koilocytic changes may be observed and because HPV has been found in cutaneous squamous-cell carcinomas and premalignant keratoses in immunosuppressed patients. We analyzed DNA extracted from 39 keratoacanthomas from 22 "at-risk" patients (nine patients undergoing UV light and/or anthralin therapy for psoriasis, 10 solid organ transplant recipients, one patient with xeroderma pigmentosa, one patient with acquired immunodeficiency syndrome, and one patient undergoing therapy for non-Hodgkin's lymphoma) for the presence of HPV. The results were compared with analyses of DNA extracted from 30 keratoacanthomas from 28 patients at no known increased risk for these lesions. Using polymerase chain reaction (PCR) primers designed to detect multiple HPV types (including 6, 11, 16, 18, 31, and 33), HPV was detected in seven keratoacanthomas from six of the at-risk patients and in eight sporadic keratoacanthomas from eight patients without risk factors. HPV was also present in one of 26 nonlesional skin controls. Statistical analysis showed a significant difference in the prevalence of HPV DNA sequences found in keratoacanthomas compared to normal control skin (p = 0.038). The presence of virus by PCR could not be predicted by histologic evaluation. Sequence analysis showed the presence of HPV types 11, 13, 24, 33, and 57. Although these results confirm the frequent presence of HPV in keratoacanthomas, the role of this virus in the etiology and pathogenesis of these lesions remains to be elucidated.