Dark homogeneous streak dermoscopic pattern correlating with specific KIT mutations in melanoma.
OBJECTIVE
Mutations driving melanoma growth have diagnostic, prognostic, and therapeutic implications. Traditional classification systems do not correlate optimally with underlying melanoma growth-promoting mutations. Our objective was to determine whether unique dermoscopic growth patterns directly correlate with driving mutations.


METHODS
We evaluated common driving mutations in 4 different dermoscopic patterns (rhomboidal, negative pigmented network, polygonal, and dark homogeneous streaks) of primary cutaneous melanomas; 3 melanomas per pattern were tested. Three of the 4 patterns lacked common mutations in BRAF, NRAS, KIT, GNAQ, and HRAS. One pattern, the dark homogeneous streaks pattern, had unique KIT mutations in the second catalytic domain of KIT in exon 17 for all 3 samples tested. Two tumors with the dark homogeneous streaks pattern turned out to be different primary melanomas from the same patient and had different sequence mutations but had an impact on the same KIT domain.


CONCLUSIONS
While future study is required, these results have multiple implications. (1) The underlying melanoma-driving mutations may give rise to specific dermoscopic growth patterns, (2) BRAF/NRAS mutations in early melanomas may not be as common as previously thought, and (3) patients may be predisposed to developing specific driving mutations giving rise to melanomas or nevi of similar growth patterns.
Department of Dermatology and Cutaneous Surgery, University of Miami Miller School of Medicine, Miami, Florida.
Margaret I
MI
Sanchez
Department of Dermatology and Cutaneous Surgery, University of Miami Miller School of Medicine, Miami, Florida.
Harold S
HS
Rabinovitz
Department of Dermatology and Cutaneous Surgery, University of Miami Miller School of Medicine, Miami, Florida.
Margaret C
MC
Oliviero
Department of Dermatology and Cutaneous Surgery, University of Miami Miller School of Medicine, Miami, Florida.
George W
GW
Elgart
Department of Dermatology and Cutaneous Surgery, University of Miami Miller School of Medicine, Miami, Florida.
Carmen
C
Perez
Melanoma Unit, Dermatology Department, Hospital Clinic of Barcelona, IDIBAPS, Barcelona, Spain3CIBER de Enfermedades Raras, Instituto de Salud Carlos III, Barcelona, Spain.
Susana
S
Puig
Melanoma Unit, Dermatology Department, Hospital Clinic of Barcelona, IDIBAPS, Barcelona, Spain3CIBER de Enfermedades Raras, Instituto de Salud Carlos III, Barcelona, Spain.
Josep
J
Malvehy
Department of Dermatology and Cutaneous Surgery, University of Miami Miller School of Medicine, Miami, Florida.
James M
JM
Grichnik
D046169:Dermoscopy; D006801:Humans; D008545:Melanoma / Q000235:genetics* / Q000473:pathology*; D009154:Mutation; D019009:Proto-Oncogene Proteins c-kit / Q000235:genetics*; D012878:Skin Neoplasms / Q000235:genetics* / Q000473:pathology*
D019009:Proto-Oncogene Proteins c-kit