Fig. 36.2 Velvety hyperpigmentation of the neck crease in a patient with classic acanthosis nigricans. (Courtesy of James E. Fitzpatrick, MD.)
Acanthosis nigricans presents as velvety, hyperpigmented plaques, most commonly in neck creases and axillae (Fig. 36-2). The patient may complain about “dirty skin” under the arms that is impossible to clean. The tops of knuckles may also demonstrate small papules.
