Porokeratosis is a disorder of epidermal keratinization characterized clinically
by a distinctive ridge-like border, and histologically by cornoid lamellae. The
known clinical variants of porokeratosis are: classic porokeratosis of Mibelli,
disseminated superficial (actinic) porokeratosis (DSAP), porokeratosis palmaris
et plantaris disseminata, linear porokeratosis and punctate porokeratosis. In
1995, a seventh form was described as porokeratosis ptychotropica: a verrucous
form resembling psoriasis involving the gluteal cleft presenting on the
histological exam multiple cornoid lamellae. There are very few reports in the
literature of this clinical variant. The present study describes the case of a
healthy male presenting gluteal hyperkeratotic plaques for 22 years. He had been
to several dermatologists, none of them had achieved a definitive diagnosis. We
present a typical clinical presentation and its dermoscopy findings, in addition
to histological examination that confirmed the diagnosis.