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Porokeratosis
Porokeratosis is a clonal disease of the epidermis
presenting in the patterns of a keratosis, or a nevoid process. It is distinguished by angulated indentations in the epidermis along the surface of the skin, or in the ostia of skin appendages. Columns of parakeratotic and orthokeratotic debris fit into the indentations and project above the skin surface (cornoid lamellae). In nevoid variants, the epidermis generally is hyperplastic and may show prominent rete patterns; verrucoid patterns may be represented. In such lesions, the zones of parakeratosis may be diffuse along the surface without a well-defined cornoid lamella.
In the disseminated, superficial, actinic variant, the lesions are multiple. Generally cornoid lamellae are well-defined; they are found at the periphery of the lesions, along the surface within such lesions, and in
the ostia of skin appendages.
Regression is common within lesions of DSAP. Regression is mediated at the level of a lichenoid reaction. Lesions with prominent regression take on a poikilodermatous quality (senescent lichenoid reaction).
Keratinocytic dysplasia may be a feature of lesions of DSAP; the epidermis of such lesions comes to resemble that of an actinic keratosis. Epidermoid carcinoma may have an origin is such lesions.
Mizukawa Y, Shiohara T: Onset of porokeratosis of Mibelli in organ transplant patients: lack of search for transmissible agents in these patients. J Am Acad Dermatol 2001; 44:143-4.
Kanitakis J, et al: Porokeratosis in organ transplant recepients. J Am Acad Dermatol 2001; 44:144-5.
Jurecka W, Neumann RA, Knobler RM: Porokeratoses: immunohistochemical, light, and electron microscopic evaluation. J Am Acad Dermatol 1991:24: 96-101.
Reed RJ, Leone P: Porokeratosis: a mutant clonal keratosis of the epidermis. Arch Dermatol 19: 340-7
When I see a lesion of porokeratosis, I think of a young Phil Leone.
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