Porokeratosis ptychotropica: a rare variant of porokeratosis.

BACKGROUND: Porokeratosis, a well recognized disorder of keratinization, is known to have several clinical variants. This report describes a rare variant characterized by verrucous plaques.
METHODS: An adult male presented with a slowly progressive verrucous plaque on the gluteal region that was resistant to conventional therapy. Careful inspection revealed a keratotic ridge at the plaque border leading to the diagnosis.
RESULTS: Histopathology showed the presence of multiple cornoid lamellae confirming the diagnosis of porokeratosis ptychotropica.
CONCLUSIONS: Porokeratosis ptychotropica is a rare variant of porokeratosis with fewer than 25 cases described in the literature. This report is to highlight the importance of considering this particular entity in the diagnosis of genitogluteal plaques, especially those not responding to conventional modalities.