Reflectance Confocal Microscopy for Diagnosing Facial Skin Lesions and Melanoma

Conclusions

• Reflectance confocal microscopy appears highly useful for distinguishing melanoma on sun-damaged facial skin from benign mimics such as pigmented actinic keratosis, solar lentigo, seborrheic keratosis, and LPLK.
• On the face and other sun-damaged sites, folliculocentric dendritic and pagetoid cells, especially around hair follicles and adnexal structures, are emphasized as key clues to melanoma in situ.
• RCM can prevent unnecessary biopsies when it shows classic benign patterns, but lesions with atypical or evolving features still warrant biopsy or excision.
• Several cases showed that RCM prompted clinicians to overrule an initially benign-appearing clinical or pathology impression and obtain a diagnosis of melanoma.
• Conversely, RCM also helped confidently identify benign lesions with congenital nevus-like or LPLK-like patterns, allowing monitoring instead of immediate biopsy.
• Pigmented squamous cell carcinoma in situ and pigmented actinic keratosis can closely mimic melanoma clinically and dermoscopically, but confocal patterns may help separate them.
• When dermoscopy or RCM and pathology disagree, the presentation argues for close communication with dermatopathology and, when needed, deeper sections, repeat biopsy, or additional immunostains.
• High-grade dysplastic nevus on the face should be interpreted cautiously because melanoma may be undercalled in these cases.
• Molecular gene-expression profiling was presented as a useful adjunct in difficult melanocytic lesions, sometimes supporting a melanoma diagnosis when histology was equivocal.
• The overall message is that no single test is sufficient, and the best results come from combining clinical exam, dermoscopy, RCM, pathology, and sometimes molecular testing.