Porokeratoma: A Different Entity or a Variant of Verrucous (Hyperkeratotic) Porokeratosis?
A 78-year-old man, with paraplegia secondary to poliomyelitis and ankylosing spondylarthritis, presented with a 4-year history of slightly painful and slowly growing lesions on his left buttock. The patient had been unsuccessfully treated with cryotherapy 2 years before. Clostridiopeptidase and protease ointment had been occasionally applied. On physical examination, there were six well-defined verrucous lesions, with central depressions filled with keratotic material []. There were no other skin lesions and mucous membranes were not affected. An excisional biopsy of the largest lesion was performed. The lesion consisted of an acanthotic epidermis with low papillomatosis and overlying compact orthokeratosis []. Scattered throughout the lesion were multiple epidermal depressions containing cornoid lamella below which the granular layer was absent and dyskeratotic keratinocytes were identified [Figures and ]. Immunohistochemical studies for human papillomavirus resulted negative. The diagnosis of porokeratoma was made.