HUMAN PAPILLOMAVIRUS TYPE 60-ASSOCIATED PLANTAR WART - RIDGED WART

Background: We had recently cloned a new cutaneous human papillomaviru s type 60 (HPV-60) from a plantar cyst with characteristic pathologic changes and identified it in additional cysts. However, it is not know n whether or not HPV-60 infection causes the other cutaneous lesions. Observations: Six plantar warts were found in five patients. These war ts were found either with concomitant plantar cysts (four patients) or without an accompanying cyst (one patient). All warts showed a simila r clinical appearance, including a smooth and slightly elevated surfac e and the retained appearance of the dermal ridges. Their histopatholo gic features were identical to those found in the wall of the cysts re ported previously, namely hyperkeratosis with vacuolated structure wit h or without nuclei in the horny layer and amorphous eosinophilic cyto plasmic inclusions in the cells with peripherally located nuclei in th e granular and prickle cell layers. By Southern blot analysis, all war ts were found to harbor HPV-60 DNA. In addition, immunohistochemistry and in situ hybridization analysis revealed the presence of viral caps id antigen and viral genome in these lesions, respectively. Conclusion : We conclude that HPV-60 infection on the plantar skin causes the war ty lesion, designated as ridged walt, distinct from those infected wit h other cutaneous human papillomaviruses.