Plantar Warts (Verruca Plantaris)
Most plantar warts are caused by HPV1. In some cases, HPV4 produces a crop of smaller, painless warts on the foot, referred to as mosaic plantar warts. Plantar warts may be nodular, ridged, pigmented or cystic. Pigmented plantar warts are caused by HPV4, 60, and 65. The cystic variant resembles epidermoid cyst and is caused by HPV60. This image shows prominent intracytoplasmic eosinophilic inclusions (top) as well as basophilic keratohyalin granules (the result of viral cytopathic effects).