Optical Imaging to Detect Lentigo Maligna

In an article published online on January 26 in the Journal of the American Academy of Dermatology, my colleagues and I (Menge et al) reported on the use of reflectance confocal microscopy (RCM) for challenging facial lesions. We studied the diagnosis of lentigo maligna (LM) based on RCM versus the histopathologic diagnosis after biopsy.

In this study 17 patients were seen for evaluation of known or suspected LM at Memorial Sloan Kettering Cancer Center (New York, New York). Among these patients, a total of 63 sites on the skin were evaluated using RCM and a presumptive diagnosis was made. These sites were then biopsied to compare the diagnosis using RCM with that made by histopathology. When LM was present as determined by biopsy, RCM also was able to detect it 100% of the time (sensitivity). When LM was absent as determined by biopsy, RCM also indicated it was absent 71% of the time (specificity).

What’s the issue?

Lentigo maligna is a form of melanoma in situ occurring on sun-damaged skin. It can be quite subtle to detect clinically and therefore may go undiagnosed for a while. Lentigo maligna also has been shown to have notable subclinical extension with which traditional surgical margins for truncal melanoma may be too narrow to clear LM on the head and neck. Therefore, presurgical consultation may be difficult due to the amorphous borders. Random blind biopsies also are discouraged because of sampling error.

Additionally, repetitive biopsies over time, which may be frequently needed in individuals with heavy sun exposure, can be costly and cause adverse effects.

This study showed the usefulness and reliability of using RCM for challenging facial lesions that are suspicious for LM. The sensitivity and specificity of RCM in this study indicated that this technology performs well in detecting LM when present; however, false-positives were noted in this study. False-positives included pigmented actinic keratosis and melanocytosis. Dermatologists who are advanced in RCM technology and interpretation also were utilized in this study. More research is needed to understand how to best utilize this technology, but overall the ability of RCM to accurately identify LM without biopsy represents an exciting new development in how dermatologists can better diagnose, manage, and treat melanoma.

How will you adopt advances in cutaneous noninvasive imaging?

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