<unk>  may be divided into the following clinical types: * Plaque-type<unk>  (also known as "Classic<unk> " and<unk>  of Mibelli") 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<unk> . Squamous cell carcinomas have been reported to develop in Mibelli's type<unk>  over partianal areas involving anal mucosa. This was the first report mentioning mucosal malignancy in any form of<unk> . * Disseminated superficial<unk>  is a more generalized processes and involves mainly the extremities in a bilateral, symmetric fashion. In about 50% of cases, skin lesions only develop in sun-exposed areas, and this is referred to as disseminated superficial actinic<unk>  *<unk>  palmaris et plantaris disseminata is characterized by skin lesions that are superficial, small, relatively uniform, and demarcated by a distinct peripheral ridge of no more than 1mm in height. * Linear<unk>  is characterized clinically skin lesions are identical to those of classic<unk> , including lichenoid papules, annular lesions, hyperkeratotic plaques with central atrophy, and the characteristic peripheral ridge. * Punctate<unk>  is a skin condition associated with either classic<unk>  or linear<unk>  types of<unk> , and is characterized by multiple, minute, and discrete punctate, hyperkeratotic, seed-like skin lesions surrounded by a thin, raised margin on the palms and soles. *<unk>  plantaris discreta is a skin condition that occurs in adults, with a 4:1 female preponderance, characterized by a sharply marginated, rubbery, wide-based papules. It is also known as "Steinberg's lesion". It was characterized in 1970.
Porokeratosis
Hyperkeratosis
Hypodermyasis
Granulomatous slack skin
Arsenical keratosis
Reactional keratosis
Dysplastic nevus
Epidermolytic hyperkeratosis