acanthosis

An increase in the thickness of the stratum spinosum of the epidermis. [acantho- + G. -osis, condition]

- glycogenic a. elevated gray-white plaques of distal esophageal or vaginal mucosa, with epithelium thickened by proliferation of large glycogen-filled squamous cells.

- a. nigricans an eruption of velvet warty benign growths and hyperpigmentation occurring in the skin of the axillae, neck, anogenital area, and groin; in adults, may be associated with internal malignancy, endocrine disorders, or obesity; a benign hereditary type occurs in children. SEE ALSO: pseudoacanthosis nigricans. [L. fr. niger, black]

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ac·an·tho·sis -'thō-səs n, pl -tho·ses -.sēz a benign overgrowth of the stratum spinosum of the skin

ac·an·thot·ic -'thät-ik adj

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n.

an increase in the number of prickle cells in the innermost layer of the epidermis, leading to thickening of the epidermis. Acanthosis nigricans is believed to be associated with insulin resistance; it is characterized by papillomatous growths, mainly in the armpits, giving the skin a pigmented appearance and a velvety texture. It may be benign or malignant. Pseudoacanthosis nigricans is more common and is associated with obesity.

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ac·an·tho·sis (ak″an-thoґsis) [acanth- + -osis] diffuse hyperplasia of the spinous layer of the skin. Called also hyperacanthosis.