What is acanthosis nigricans - Definition of acanthosis nigricans

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What is acanthosis nigricans?

Acanthosis nigricans (AN) is a skin condition characterized by hyperpigmentation. In this dermatological condition, poorly defined symmetrical hyperkeratosis and verrucous plaques develop giving the affected area of the skin a velvety texture.

Usually acanthosis nigricans affects the intertriginous areas of skin like the axilla of the arm, the anogenital region, submammary region, groins and sides of the neck.
In very rare cases the condition may be generalized as seen in the image. Occasionally mucocutaneous areas may get affected.

'Acanthosis' is diffused thickening (hyperplasia) of epidermal skin.
There is increased thickness of stratum basale and stratum spinosum. It is derived from the Greek word "Acanthus" meaning "thorn".
In the advanced condition, verrucous plaques giving spiny appearance may develop.
The word "nigricans", is from the Latin, meaning "becoming black".

Acrochorda (fibroepithelial polyps), small benign tumors, are usually associated with AN. There are benign and malignant forms of acanthosis nigricans. The causes of this disorder include, obesity, endocrine abnormalities and genetic inheritance. Malignant forms may involve mucous membranes and are usually associated with gastrointestinal and genitourinary cancers. Treating the causative factors gradually resolves the condition in most of the cases.

picture of acanthosis nigricans affected back

Acanthosis nigricans definition

by wordnetweb.princeton.edu/:
"a skin disease characterized by dark wartlike patches in the body folds; can be benign or malignant."

Medical definition

by www.merriam-webster.com:
"a skin disease characterized by gray-black warty patches usually situated in the axilla or groin or on elbows or knees and sometimes associated with cancer of abdominal viscera."

Encyclopedic definition

by en.wikipedia.org:
"Acanthosis nigricans is a brown to black, poorly defined, velvety hyperpigmentation of the skin."

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Image source: http://en.wikipedia.org/wiki/File:Familial_acanthosis_nigricans2.jpg

Authors: Vandana Mehta Rai MD DNB, C Balachandran MD | License: CC BY-SA 3.0
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What is acanthosis nigricans and its definition.