Dark pigmented lesions: Diagnostic accuracy of dermoscopy and reflectance confocal microscopy in a tertiary referral center for skin cancer diagnosis

The reported prevalence of nevus-associated melanoma varies substantially. We performed a systematic review and meta-analysis to determine the incidence and prevalence of this disease; we also performed subanalyses considering age, tumor thickness, and nevus-type classification. In 38 observational cohort and case-control studies, 29.1% of melanomas likely arose from a preexisting nevus and 70.9% de novo. Any given melanoma was 64% less likely to be nevus-associated than de novo (risk ratio 0.36, 95% confidence interval [CI] 0.29-0.44; P < .001; I2 = 99%); nevus-associated melanomas had a lower mean Breslow thickness than de novo melanomas (mean difference -0.39 mm; 95% CI -0.60 to -0.18; P = .0003; I2 = 66%). No significant differences were noted regarding the association of nevus-associated melanomas with nondysplastic nevi or dysplastic nevi (risk ratio 0.77, 95% CI 0.49-1.20; P = .24; I2 = 98%).

Dermatoscopy increases both the sensitivity and specificity of melanoma diagnosis. Reflectance confocal microscopy (RCM) is a noninvasive technique that complements dermatoscopy in the evaluation of equivocal lesions at cellular resolution. To determine prospectively the potential impact of confocal microscopy when implemented in a routine melanoma diagnosis workflow. Patients referred to a single melanoma clinic were consecutively enrolled. At dermatoscopy, patients were referred to one of the following pathways: (i) no further examination or (ii) RCM examination. On examination atypical lesion(s) were referred for either (a) RCM documentation (lesions with consistent suspicious clinical/dermatoscopic criteria, already qualified and scheduled for surgical excision) or (b) RCM consultation for equivocal lesions, where RCM diagnosis would determine lesion definite outcome (excision or digital follow-up). Reflectance confocal microscopy examination was performed for 41% of 1005 patients enrolled. In two-thirds of these cases RCM influenced the lesion outcome. The systematic application of RCM for equivocal lesions saved over 50% of benign lesions from unnecessary excision. The number needed to excise a melanoma was 6·8 with RCM examination, compared with a hypothetical 14·6 without RCM evaluation. Reflectance confocal microscopy as a second-level examination to dermatoscopy proved to be highly accurate in diagnosis and reduced the number of unnecessary excisions. Improved accuracy, considering that RCM enabled the detection of the six melanomas (2%) in the group of 308 lesions eligible for follow-up, also minimizes the risk of referring a melanoma to digital dermatoscopy monitoring, and potentially losing the patient to follow-up. © 2014 British Association of Dermatologists.