Acanthosis nigricans

Acanthosis nigricans is a benign skin disease that often reflects an underlying medical condition.

Most commonly associated with obesity and insulin resistance.

Rarely, cases may be related to underlying malignancy and, where no other association is identified, malignancy screening is warranted.

Treatment is usually unnecessary unless lesions are extensive or cosmetically unacceptable and do not resolve with treatment of the underlying condition.

Acanthosis nigricans (AN) is a cutaneous disorder manifested by symmetric, hypertrophic, papillomatous, velvety, hyperpigmented plaques commonly found on flexural and intertriginous areas.[1]Das A, Datta D, Kassir M, et al. Acanthosis nigricans: a review. J Cosmet Dermatol. 2020 Aug;19(8):1857-65. http://www.ncbi.nlm.nih.gov/pubmed/32516476?tool=bestpractice.com It is associated with a wide array of medical conditions. AN may present at birth or in early childhood with a familial association, but is most commonly associated with obesity and an insulin-resistant state.[2]Schwartz RA. Acanthosis nigricans. J Am Acad Dermatol. 1994 Jul;31(1):1-19. http://www.ncbi.nlm.nih.gov/pubmed/8021347?tool=bestpractice.com [3]Curth HO. Classification of acanthosis nigricans. Int J Dermatol. 1976 Oct;15(8):592-3. http://www.ncbi.nlm.nih.gov/pubmed/971978?tool=bestpractice.com ​​[4]Berk DR, Spector EB, Bayliss SJ. Familial acanthosis nigricans due to K650T FGFR3 mutation. Arch Dermatol. 2007 Sep;143(9):1153-6. http://www.ncbi.nlm.nih.gov/pubmed/17875876?tool=bestpractice.com ​​[5]Brickman WJ, Binns HJ, Jovanovic BD, et al. Acanthosis nigricans: a common finding in overweight youth. Pediatr Dermatol. 2007 Nov-Dec;24(6):601-6. http://www.ncbi.nlm.nih.gov/pubmed/18035980?tool=bestpractice.com ​​[6]Kong AS, Williams RL, Rhyne R, et al. Acanthosis nigricans: high prevalence and association with diabetes in a practice-based research network consortium-a PRImary care Multi-Ethnic network (PRIME Net) study. J Am Board Fam Med. 2010 Jul-Aug;23(4):476-85. https://www.jabfm.org/content/23/4/476 http://www.ncbi.nlm.nih.gov/pubmed/20616290?tool=bestpractice.com [7]Maguolo A, Maffeis C. Acanthosis nigricans in childhood: a cutaneous marker that should not be underestimated, especially in obese children. Acta Paediatr. 2020 Mar;109(3):481-7. http://www.ncbi.nlm.nih.gov/pubmed/31560795?tool=bestpractice.com ​ Obesity-associated AN correlates with increasing body mass index, female sex, and Hispanic or black ethnicity.[5]Brickman WJ, Binns HJ, Jovanovic BD, et al. Acanthosis nigricans: a common finding in overweight youth. Pediatr Dermatol. 2007 Nov-Dec;24(6):601-6. http://www.ncbi.nlm.nih.gov/pubmed/18035980?tool=bestpractice.com ​​​ Malignancy-associated AN is rare and most often occurs with gastric adenocarcinoma, but may also be secondary to other carcinomas and lymphomas.[8]Moore RL, Devere TS. Epidermal manifestations of internal malignancy. Dermatol Clin. 2008 Jan;26(1):17-29. http://www.ncbi.nlm.nih.gov/pubmed/18023768?tool=bestpractice.com [9]Curth HO. Cancer associated with acanthosis nigricans: a review of the literature and report of a case of acanthosis nigricans with cancer of the breast. Arch Surg. 1943 Dec;47(6):517-52.[10]Rigel DS, Jacobs MI. Malignant acanthosis nigricans: a review. J Dermatol Surg Oncol. 1980 Nov;6(11):923-7. http://www.ncbi.nlm.nih.gov/pubmed/6257767?tool=bestpractice.com ​[Figure caption and citation for the preceding image starts]: Acanthosis nigricans involving the axilla of an obese Caucasian womanFrom the collection of Melvin Chiu, MD [Citation ends].​​