There is no clinical term for acanthosis nigricans, but patients should be referred to acanthosis nigricans. Acanthosis nigricans is a clinical skin disease that tends to occur in the skin folds. It is often seen in the neck, armpits, groin, and buttocks. Localized skin may show obvious papillary or villous hyperplasia, and localized hyperpigmentation and roughness of the skin may also occur. However, acanthosis nigricans is often clinically classified as benign or malignant, and benign acanthosis nigricans is often closely related to genetics and obesity. Benign acanthosis nigricans tends to recede with age or after weight loss. However, the occurrence of malignant acanthosis nigricans is often closely related to the malignant tumor that the patient has.