Linear porokeratosis presenting as erosions in the newborn period

Porokeratoses-A Comprehensive Review on the Genetics and Metabolomics, Imaging Methods and Management of Common Clinical Variants

Porokeratosis is a heterogeneous group of keratinising disorders characterised by the presence of particular microscopic structural changes, namely the presence of the cornoid lamella. This structure develops as a consequence of a defective isoprenoid pathway, critical for cholesterol synthesis. Commonly recognised variants include disseminated superficial actinic porokeratosis, disseminated superficial porokeratosis, porokeratosis of Mibelli, palmoplantar porokeratosis (including porokeratosis palmaris et plantaris disseminata and punctate porokeratosis), linear porokeratosis, verrucous porokeratosis (also known as genitogluteal porokeratosis), follicular porokeratosis and porokeratoma. Apart from the clinical presentation and epidemiology of each variant listed, this review aims at providing up-to-date information on the precise genetic background, introduces imaging methods facilitating the diagnosis (conventional and ultraviolet-induced fluorescence dermatoscopy, reflectance confocal microscopy and pathology), discusses their oncogenic potential and reviews the literature data on the efficacy of the treatment used, including the drugs directly targeting the isoprenoid-mevalonate pathway.

Linear porokeratosis associated with disseminated superficial actinic porokeratosis: a new example of type II segmental involvement

The coexistence of linear porokeratosis (LP) and disseminated superficial actinic porokeratosis (DSAP) in a 3-year-old girl with a family history of DSAP is presented. Happle proposed loss of heterozygosity (LOH) to explain the origin of this unusual phenomenon. Homozygosity would explain why lesions in LP are far more pronounced than those of the associated heterozygous DSAP lesions. LOH would also explain the early age of presentation of the linear lesions, the family history of DSAP, and why LP cases are particularly prone to malignant transformation. This case is also important for molecular studies because of the presence of heterozygous and homozygous mutated cells in the same patient and the familial occurrence of the heterozygous form of the disease.