What is "acanthosis nigricans"

n. (context pathology English) A skin disease, sometimes associated with cancer, exhibiting grey or black wart-like growths near the major joints.

n. a skin disease characterized by dark wart-like patches in the body folds; can be benign or malignant [syn: keratosis nigricans]

Acanthosis nigricans is a brown to black, poorly defined, velvety hyperpigmentation of the skin. It is usually found in body folds, such as the posterior and lateral folds of the neck, the armpits, groin, navel, forehead, and other areas.