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any horny growth, such as a wart or callosity.
actinic keratosis a sharply outlined wartlike or keratotic growth, which may develop into a cutaneous horn, and may become malignant; it usually occurs in the middle aged or elderly and is due to excessive exposure to the sun. Called also senile or solar keratosis. (See Atlas 3, Part F).
keratosis follicula´ris a slowly progressive autosomal dominant disorder of keratinization characterized by pinkish to tan or skin-colored papules on the seborrheic areas of the body that coalesce to form plaques, which may become crusted and secondarily infected; over time, the lesions may become darker and may fuse to form papillomatous and warty malodorous growths. Called also Darier's disease and Darier-White disease.
keratosis palma´ris et planta´ris palmoplantar keratoderma.
keratosis pharyn´gea horny projections from the tonsils and pharyngeal walls. Called also pharyngokeratosis.
keratosis pila´ris hyperkeratosis limited to the hair follicles.
keratosis puncta´ta a hereditary hyperkeratosis in which the lesions are localized in multiple points on the palms and soles.
seborrheic keratosis (keratosis seborrhe´ica) a benign, noninvasive tumor of epidermal origin, marked by numerous yellow or brown, sharply marginated, oval, raised lesions.
senile keratosis (solar keratosis) actinic keratosis.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.


, pl.


(ker'ă-tō'sis, -sēz),
Any lesion on the epidermis marked by the presence of circumscribed overgrowths of the horny layer.
[kerato- + G. -osis, condition]
Farlex Partner Medical Dictionary © Farlex 2012


n. pl. kerato·ses (-sēz)
Excessive growth of horny tissue of the skin.

ker′a·tot′ic (-tŏt′ĭk) adj.
The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.


Dermatology A condition characterized by ↑ keratin production See Actinic keratosis, Seborrheic keratosis, Stucco keratosis.
McGraw-Hill Concise Dictionary of Modern Medicine. © 2002 by The McGraw-Hill Companies, Inc.


, pl. keratoses (ker'ă-tō'sis, -sēz)
Any lesion on the epidermis marked by the presence of circumscribed overgrowths of the horny layer.
[kerato- + G. -osis, condition]
Medical Dictionary for the Health Professions and Nursing © Farlex 2012


(ker?a-to'sis) (-to'sez?) plural.keratoses [ kerato- + -osis]
1. Growth of the horny layer of the skin; a callus, callosity, or keratoma.
2. Any condition of the skin characterized by the formation of horny growths or excessive development of the horny growth. keratotic (?a-tot'ik), adjective Synonym: keratoma
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ACTINIC KERATOSIS: Actinic skin damage on forehead and scalp

actinic keratosis

Abbreviation: AK
A rough, sandpaper-textured, premalignant macule or papule caused by excess exposure to ultraviolet light. AKs often appear on facial skin (such as near the eyes, on the nose, on the ears, or the lips) and the parts of the body that receive the most sunlight exposure. Prevention of AKs depends on limiting one's exposure to sunlight, beginning in childhood and continuing throughout life. See: illustration


Liquid nitrogen destroys these lesions and prevents them from progressing to other cancers of the skin.

Synonym: solar keratosis See: sunscreen

keratosis follicularis

Darier's disease.

keratosis nigricans

Acanthosis nigricans.

oral keratosis

Keratinization of the mucosa of the mouth to an unusual extent, or in locations normally not keratinized, as a result of an inherited autosomal dominant gene or the more common effect of tobacco and other carcinogens.

keratosis palmaris et plantaris

A congenital abnormality of the palms and soles, characterized by a dense thickening of the keratin layer in these regions.

keratosis pharyngis

Horny projections from the pharyngeal tonsils and adjacent lymphoid tissue.

keratosis pilaris

Chronic inflammatory disorder of area surrounding the hair follicles. It is often found in patients with atopic dermatitis. Synonym: lichen pilaris; lichen spinulosus


The disorder is characterized by an accumulation of horny material at follicular orifices of persons with rough, dry skin. It is most pronounced in winter on lateral aspects of thighs and upper arms with possible extension to legs, forearms, and scalp.


There is no specific therapy, but keratolytic lotions may be of some value.

keratosis punctata

Discrete horny projections from the sweat pores of the palms and soles.
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seborrheic keratosis

A benign skin tumor that may be pigmented. It is composed of immature epithelial cells and is quite common in older adults. Its etiology is unknown.


Keratoid, nevoid, acanthoid, or verrucose types occur in older adults and in those with long-standing dry seborrhea, on the face, scalp, interscapular or sternal regions, and backs of the hands. The yellow, gray, or brown sharply circumscribed lesions are covered with a firmly adherent scale, greasy or velvety on the trunk or scalp but harsh, rough, and dry on the face or hands.


Thorough curettage is effective. This leaves a flat surface that becomes covered with normal skin within about 1 week. Pedunculated lesions can be removed surgically. Cautery may produce scarring and should not be used.

Synonym: wart, seborrheic See: illustration

keratosis senilis

An inaccurate synonym for actinic keratosis, which is caused by accumulated ultraviolet light exposure, not by aging.

smokeless tobacco keratosis

Tobacco pouch keratosis.

snuff keratosis

Tobacco pouch keratosis.

solar keratosis

Actinic keratosis.
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STUCCO KERATOSIS: White warty lesions of the dorsum of the fist

stucco keratosis

Benign papules, typically found on the lower extremities, histologically related to seborrheic keratoses. See: illustration

tobacco pouch keratosis

A white, corrugated lesion found on the oral mucosa usually in the muccobuccal fold where chewing tobacco has been habitually placed.
Synonym: smokeless tobacco keratosis; snuff keratosis
Medical Dictionary, © 2009 Farlex and Partners


Small white patches in the skin arising from excessive local reproduction of the horny outer cells, so that more than the normal amount of KERATIN is formed. Solar keratosis, caused in the elderly by over-exposure to the sun, is a precancerous condition. Keratosis may also affect the hair follicles causing baldness, the outer and middle ears causing obstruction of the ear canal and CHOLESTEATOMA, and the mucous membranes of the lip and of the throat.
Collins Dictionary of Medicine © Robert M. Youngson 2004, 2005


A skin disease characterized by an overgrowth of skin, which usually appears discolored.
Mentioned in: Hyperpigmentation
Gale Encyclopedia of Medicine. Copyright 2008 The Gale Group, Inc. All rights reserved.


, pl. keratoses (ker'ă-tō'sis, -sēz)
Any epidermal lesion marked by circumscribed overgrowths of horny layer.
[kerato- + G. -osis, condition]
Medical Dictionary for the Dental Professions © Farlex 2012
References in periodicals archive ?
Age, y/Sex Site Diagnosis 4 17/F Cheek Folliculitis 10 55/F Leg Basal cell carcinoma 38 37/F Cheek Fibrous papule 45 38/F Back Solar lentigo 105 75/F Arm Scar 113 69/M Finger Actinic keratosis 125 40/F Unknown Basal cell carcinoma 160 69/M Canthus Ruptured cyst 189 44/F Chest Hemangioma 225 70/F Nose Seborrheic keratosis 296 64/M Forehead Basal cell carcinoma 307 46/M Forehead Basal cell carcinoma 345 72/M Breast Verrucous keratosis 346 77/F Breast Benign lichenoid keratosis 407 67/F Cheek Actinic keratosis 432 44/F Neck Syringoma 447 37/F Shoulder Benign lichenoid keratosis 472 56/F Nose Fibrous papule 479 42/F Shoulder Nevus Case No.
* The report reviews pipeline therapeutics for Actinic (Solar) Keratosis by companies and universities/research institutes based on information derived from company and industry-specific sources
Keratoses may be graded as mild moderate or severe depending on the extent and severity.2 In the early stages of keratosis (mild variety) the involved skin has an indurated gritty character with papules less than 2 mm in size that can be best appreciated by palpation.
Keratosis obturans has been confused with EACC in the past; however, there are important differences between the two entities, both clinically and pathophysiologically (2).
Dermoscopic clues for diagnosing melanomas that resemble seborrheic keratosis. JAMA Dermatol.
Seborrheic keratosis (SK) is also known as seborrheic wart, senile wart and basal cell papilloma.
The American Academy of Dermatology says a seborrheic keratosis may seem worrisome because it can look like a wart, a precancerous skin growth or even skin cancer.
KX2-391, also known as KX-01, is a first-in-class dual Src kinase and tubulin polymerization inhibitor in Phase III development as a topical medicinal product for the treatment of actinic keratosis. Actinic keratosis is a common skin condition that is induced through ultra-violet light damage, resulting in patches of thick, scaly, or crusty skin.
The patient was treated with topical 5% salicylic acid in petrolatum for 2 weeks and oral acitretin for 2 months and showed significant improvement predominantly on the keratosis (Figure 3).
In the case we report, the leukoplakia was due to actinic keratosis (AK) also known as solar keratosis, of the tarsal conjunctiva and eyelid margin.
Though cases of the EACC have been reported as early as 1850 by Toynbee [4] and 1893 by Scholefield [5], some authors speculate that they might have represented keratosis obturans due to similar characteristics [2].