Detection of human papillomavirus type 60 in plantar cysts and verruca plantaris by the in situ hybridization method using digoxigenin labeled probes.

BACKGROUND: Since 1987, many cases have been reported in which human papillomavirus (HPV) could be associated with epidermoid cysts of the palms and soles. In 1989, the HPV found in an induced epidermoid cyst was cloned and named HPV 60.
OBJECTIVE: Our purpose was to examine the relationship of HPV 60 to plantar cysts.
METHODS: Ten cases of plantar cysts and two cases of verruca plantaris containing single inclusion bodies were obtained by biopsy and examined by the in situ hybridization (ISH) method with a digoxigenin labeled HPV 60 DNA probe.
RESULTS: Six of ten cases were found to have cytopathic effect (CPE) in the cyst wall and inner contents of the cyst. HPV 60 was detected in these cases by ISH. Two cases of verruca plantaris showing CPE also demonstrated the presence of HPV 60. Of the six HPV type 60 positive cases, four cases also showed CPE in the overlying epidermis.
CONCLUSION: At first, punctate keratotic lesions are induced by HPV 60. HPV 60 induces irregular elongation of the rete ridges into the dermis. Plantar cysts probably form as a result of the traumatic implantation of HPV 60 infected epidermis with irregularly long and narrow rete ridges into the dermis.