Dark homogeneous streak dermoscopic pattern correlating with specific KIT mutations in melanoma

Area of Science:

• Dermatology
• Oncology
• Genetics

Background:

• Melanoma classification systems lack optimal correlation with growth-driving mutations.
• Understanding these mutations is crucial for diagnosis, prognosis, and treatment of melanoma.

Purpose of the Study:

• To investigate the direct correlation between unique dermoscopic melanoma growth patterns and specific driving mutations.
• To determine if visual patterns can predict underlying genetic alterations in melanoma.

Main Methods:

• Evaluation of common driving mutations (BRAF, NRAS, KIT, GNAQ, HRAS) in four distinct dermoscopic patterns of primary cutaneous melanomas.
• Genetic analysis of three melanomas per pattern.

Main Results:

• Three out of four dermoscopic patterns showed no common BRAF, NRAS, KIT, GNAQ, or HRAS mutations.
• The dark homogeneous streaks pattern consistently revealed unique KIT mutations within the second catalytic domain (exon 17) in all tested samples.
• Two melanomas from the same patient exhibiting the dark homogeneous streaks pattern had different mutations impacting the same KIT domain.

Conclusions:

• Specific dermoscopic growth patterns may arise from distinct melanoma-driving mutations.
• BRAF/NRAS mutations might be less prevalent in early-stage melanomas than previously assumed.
• Individual predisposition to specific mutations could lead to melanomas or nevi with similar growth patterns.