A Case of Peculiar Plantar Warts

Abstract

Various kinds of viral warts have their own typical clinical appearances and histologic properties. From each of them, a corresponding unique type of human papillomavirus (HPV) has been detected. More than 60 types of HPV have been identified from the warts and other squamous cell epithelial tumors. Human papillomavirus type 60 has been identified in an epidermal cyst on the sole. We present a case of a peculiar plantar wart infected with HPV type 60. A 21-year-old male student complained of yellowish hyperkeratotic slightly elevated nodules on the right plantar arch. The surface of the nodules was not papillary, but a normal ridge pattern of the sole could be traced. Histologic findings included moderate acanthosis, papillomatosis, and eosinophilic intracytoplasmic large granules with or without surrounded vacuoles. These were noted in the middle and upper epidermis, including the hypertrophic stratum corneum. Virologic findings included HPV antigen detected by anti-HPV polyclonal antibody. The DNA of HPV type 60 was detected by in situ hybridization. A new type of plantar wart infected with HPV type 60 is reported. It shows unique clinical and histologic findings that can be distinguished from those of ordinary verruca or myrmecia on the sole.