Acanthosis Nigricans

Diagnosis: Acanthosis Nigricans

Velvety,dark-brown epidermal thickening of the neck with prominant skin folds and multiple skin tags.

Clinical Presentation

Velvety,dark-brown epidermal thickening of the neck with prominant skin folds and multiple skin tags.

Clinical History

Submitted by Alaa Saad. Originally posted October 9, 2010.

Treatment

See case discussion.

Differential Diagnosis

• Confluent and reticulated papillomatosis (Gougerot-Carteaud) • Epidermal nevus • Terra firma-forme dermatosis • Seborrheic keratosis • Tinea versicolor

Key Learnings

• Most commonly associated with insulin resistance and obesity • Can be a paraneoplastic sign — particularly gastric adenocarcinoma (malignant AN) • Malignant AN tends to be more extensive, rapidly progressive, and involves mucosal surfaces • Distribution: axillae, neck, groin, inframammary folds • Histology shows papillomatosis and hyperkeratosis with minimal acanthosis despite the name • Weight loss and treating underlying insulin resistance may improve the condition

Tags: acanthosis, nigricans, alaa saad