Porokeratosis ptychotropica

Abstract

Porokeratosis is a skin disorder clinically characterized by annular plaques with keratotic borders resembling the Great Wall of China and histopathologically by cornoid lamellae. The disease has several clinical variants. Porokeratosis ptychotropica, which has recently become part of these variants, is quite rare and little known. The entity is characterized by verrucous plaques – which may resemble a psoriasis plaque – that affect the regions of the buttocks, most commonly the gluteal cleft, with or without extremity involvement. Itching is often present. We report a rare case of porokeratosis ptychotropica and highlight its unusual manifestation (single plaque), the first case reported in the Brazilian literature.

Porokeratosis Ptychotropica on the Penis and Scrotum: A Case Report

“…Malignant transformation of porokeratosis occurs in 7.5% of cases (6). Long-term, extremity involvement, large-size lesions and ionizing radiation are the risk factors related to the malignant transformation of porokeratosis.…”

Pink verrucous plaque in a man with systemic mastocytosis

“…[1]. Immunosuppression may also play a role, as a subset of cases of porokeratosis is associated with immunosuppression [6][7][8]. These include a case of porokeratosis within the genitogluteal region associated with human immunodeficiency virus [4].…”

“…Although other variants of porokeratosis may show possible drug association, this has not yet been described in porokeratosis ptychotropica [9,10]. Malignancy arising within porokeratosis is rare and careful monitoring of these lesions is prudent [4,8].…”

Disseminated Porokeratosis with Idiopathic Thrombocytopenia - Case Report and Literature Review of Porokeratosis and Related Disorders

“…The condition is characterised by one or more atrophic patches, typically found on sun-exposed areas, surrounded by a distinctive peripheral keratotic ridge, called the cornoid lamella [ 1 ][ 2 ]. Several clinical variants have been described, as the most common among them include classic porokeratosis of Mibelli (PM), disseminated superficial actinic porokeratosis (DSAP) and its nonactinic variant disseminated superficial porokeratosis (DSP), linear porokeratosis, porokeratosis palmaris et plantaris disseminata (PPPD), punctate porokeratosis, which might represent a variant of PPPD [ 1 ][ 2 ][ 3 ].…”

“…Much less commonly reported clinical subtypes include porokeratosis ptychotropica (a verrucous variant localised in the gluteal region) [ 3 ], porokeratoma, also referred to as porokeratotic acanthoma [ 4 ], porokeratotic adnexal ostial nevus (PAON) - a rare congenital disorder of keratinization with eccrine and hair follicle involvement [ 5 ]. Although aetiology is not well - established, exposure to ultraviolet radiation, organ transplantation, chemotherapy, repetitive trauma, liver failure, chronic renal failure, hepatitis C, HIV, and other diseases associated with immunosuppression are considered risk factors which activate abnormal clones of keratinocytes [ 3 ]. Gene mutations in mevalonate pathway enzymes have also been implicated in etiopathology, such as mevalonate kinase (MVK), phosphomevalonate kinase (PMVK), mevalonate decarboxylase (MVD), and farnesyl diphosphate synthase (FDPS), as c.746 T > C and c.875A > G of the MVD gene are most common mutations [ 1 ][ 6 ].…”