Go to AAD Home
Donate For Public and Patients Store Search

Go to AAD Home

Race for the Case answers

Race for the Case Fall 2023 by Andrea Paola Caro Muñiz, MD, and Eduardo-Michelin Gomez, MD

A six-year-old female patient is seen at our outpatient clinics for evaluation of multiple scattered eczematous, scaly plaques overlying a hyperpigmented, hypertrichotic area extending from the patient’s left scapula down to her right dorsal hand (left image); the latter had been present since the patient was a one-year-old. Punch biopsy of the lesion revealed epidermal acanthosis with papillomatosis and hyperpigmentation of the basal layer, with numerous hairs in anagen stage. The patient was prescribed tacrolimus 0.1% ointment and triamcinolone acetonide 0.1% cream with significant improvement of the eczematous lesions (right image).

Illustration for Race for the Case Winter 2023

1. Which post-zygotic mutation has been associated with the development of this nevus?
Answer: AACTB, which encodes for beta-actin, has been implicated in the development of Becker’s nevus and Becker’s nevus syndrome.

2. Name the syndrome most commonly associated with this nevus.
Answer: Becker's nevus syndrome (part of the epidermal nevus syndromes): Becker's nevus with unilateral breast hypoplasia and muscle, skin, and/or skeletal abnormalities.

3. What is the phenomenon observed in the image on the left?
Answer: Wolf’s isotopic response phenomenon: the appearance of a new skin disorder at the site of another, unrelated, and often healed skin disease.


  1. Cai ED, et al. Postzygotic mutations in beta-actin are associated with Becker’s nevus and Becker’s nevus syndrome. J Invest Dermatol 2017; 137: 1795-8.

  2. Dasegowda SB, Basavaraj G, Nischal K, Swaroop M, Umashankar N, Swamy SS. Becker's Nevus Syndrome. Indian J Dermatol. 2014 Jul;59(4):421. doi: 10.4103/0019-5154.135530. PMID: 25071279; PMCID: PMC4103296.

  3. Lee JS, Park HS, Yoon HS, Cho S. Becker's Nevus with Recurrent Eczema Limited to the Nevus Lesion. Ann Dermatol. 2018 Feb;30(1):83-86. doi: 10.5021/ad.2018.30.1.83. Epub 2017 Dec 26. PMID: 29386838; PMCID: PMC5762483.

  4. Lee DJ, Kang HY. Eczema Confined to Becker's Nevus on the Face: The Behavior of Melanocytes during Inflammation. Ann Dermatol. 2012 Feb;24(1):99-100. doi: 10.5021/ad.2012.24.1.99. Epub 2012 Feb 2. PMID: 22363167; PMCID: PMC3283863.

Winter 2023 winner

Our congrats and a Starbucks gift card go out to Jill Wieser, MD, a PGY-4 dermatology resident at University Hospitals/CaseWestern Reserve University in Cleveland, Ohio. If you can solve the latest case, there may be a Starbucks gift card in your future, and you may be invited to contribute your very own Race for the Case. Better get on it now!

Note: We are now accepting submissions for new cases for 2024! If we accept your Race for the Case submission, we’ll throw in a Starbucks gift card!

Boards fodder

Download every Boards Fodder in PDF format.

DW Insights and Inquiries

Keep up with current dermatologic literature and how to use the information in practice.

Directions in Residency

Access the archive of Directions in Residency.