Second primary melanomas treated with BRAF blockers: study by reflectance confocal microscopy

Area of Science:

• Dermatology
• Oncology
• Medical Imaging

Background:

• New primary melanomas have been reported in stage IV melanoma patients receiving BRAF inhibitors.
• The cellular events within pre-existing moles under such treatment remain unclear.

Purpose of the Study:

• To investigate changing moles in patients using vemurafenib via reflectance confocal microscopy (RCM).

Main Methods:

• RCM examination of 23 lesions before excision and histopathology.
• RCM assessment of 10 lesions in two patients before and after 3 months of vemurafenib treatment.

Main Results:

• An unusual RCM pattern with marked atypia was identified in 5 lesions.
• Four nondysplastic lesions developed focal or multifocal marked atypia under vemurafenib treatment.
• Microscopic atypia correlated with histopathology and led to melanoma diagnosis.

Conclusions:

• RCM allows visualization of earliest cellular events in vemurafenib-induced changing moles.
• Microscopic marked atypia leading to melanoma diagnosis appeared during treatment, not pre-existing.