Acanthosis nigricans associated with obesity, insulin-resistant states, and endocrinopathy (also known as "Acanthosis nigricans type III") is the most common variety of acanthosis nigricans

Acanthosis 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 axilla, groin, umbilicus, forehead, and other areas.-Causes:...

, presenting with a grayish, velvety thickening of the skin on the sides of the neck, axillae, and groins. Acanthosis nigricans associated with endocrine dysfunction is more insidious in its onset, is less widespread, and the patients are often obese.