Porokeratosis

Porokeratosis may be divided into the following clinical types:) is characterized by skin lesions that start as small, brownish papules that slowly enlarge to form irregular, annular, hyperkeratotic or verrucous plaques. Sometimes they may show gross overgrowth and even horn-like structures may develop. Skin malignancy, although rare, is reported from all types of porokeratosis. Squamous cell carcinomas have been reported to develop in Mibelli's type porokeratosis over partianal areas involving anal mucosa. This was the first report mentioning mucosal malignancy in any form of porokeratosis. It was characterized in 1970. ==Genetics==

Linear porokeratosis has been associated with mutations in the PMVK and MVD genes. The PMVK gene encodes the enzyme phosphomevalonate kinase and the MVD gene encodes the enzyme diphosphomevalonate decarboxylase. ==Diagnosis==

Pathology of a case of porokeratosis showing a characteristic cornoid lamella (dark pink/red structure in the right/upper portion of the image). H&E stain. Porokeratosis has a characteristic histomorphologic feature known as a cornoid lamella. ==Treatment==