Giant congenital melanocytic nevus with vascular malformation and epidermal cysts associated with a somatic activating mutation in BRAF

Heather C Etchevers, Christian Rose, Birgit Kahle, Helmuth Vorbringer, Frédéric Fina, Pauline Heux, Irina Berger, Benjamin Schwarz, Stéphane Zaffran, Nicolas Macagno, Sven Krengel

Abstract

Giant congenital melanocytic nevi may be symptomatically isolated or syndromic. Associations with capillary malformations are exceptional, and development of epidermal cysts has not been described. A 71-year-old patient with a giant congenital melanocytic nevus (CMN) of the lower back, buttocks, and thighs was asymptomatic except for unexpected hemorrhage during partial surgical excision years before. Blunt trauma at age 64 initiated recurrent, severe pain under the nevus; multiple large epidermal cysts then developed within it. Imaging and biopsy showed a large, non-pulsatile venous malformation intermingled with the deep nevus. A low-abundance, heterozygous BRAF c.1799T>A (p.V600E) mutation was present in both gluteal and occipital congenital nevi; additional mutations in NRAS, GNAQ, GNA11, HRAS, or PIK3CA were undetectable. This is the first demonstration of a recurrent BRAF mutation in multiple large congenital nevi from the same individual, confirming that this malformation can have multiple genetic origins. Early constitutive activation of BRAF can therefore cause unusual associations of giant nevi with vascular malformations, indicating that both pigment and endothelial cell physiology may be affected by mosaic RASopathies.

Original languageEnglish
JournalPigment Cell and Melanoma Research
Volume31
Issue number3
Pages (from-to)437-441
Number of pages5
ISSN1755-1471
DOIs
Publication statusPublished - 05.2018

Research Areas and Centers

  • Centers: Center for Rare Diseases (ZSE)

DFG Research Classification Scheme

  • 205-19 Dermatology

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