Dark Coloring Around Neck. Acanthosis nigricans AN is a condition in which the skin turns dark and thick and may feel velvety. It can appear on the neck in folds of skin.

Acanthosis nigricans AN is a condition in which the skin turns dark and thick and may feel velvety. It can appear on the neck in folds of skin.
Acanthosis nigricans AN is a condition in which the skin turns dark and thick and may feel velvety.
Acanthosis nigricans AN is a condition in which the skin turns dark and thick and may feel velvety. It can appear on the neck in folds of skin. Acanthosis nigricans AN is a condition in which the skin turns dark and thick and may feel velvety.