No abstract

Small melanomas frequently reveal specific dermoscopic and confocal features. Moreover, the combination of dermoscopy and RCM can lead to a correct diagnosis of a number of naevi that share some morphological aspects with melanomas.

Background Early detection of melanoma is the main objective to ensure a high survival rate. In some cases melanoma diagnosis still remain difficult and this leads to unnecessary excisions. Objective The aim of this study was to detect the most relevant Reflectance confocal microscopy (RCM) features for the detection of dermoscopic difficult melanomas. Method A total of 322 lesions were selected from database and were evaluated on dermoscopy according to the 7‐point checklist score, in blind from histological diagnosis. We classified the lesions into three categories: (i) ‘featureless’ lesions with score ranging between 0 and 2; (ii) ‘positive‐borderline’ moles with score between 3 and 4 and (iii) ‘positive‐clear cut’ lesions with score from 5 to 10. We evaluated confocal features of the ‘featureless’ lesions and of the ‘positive‐borderline’ lesions. Evaluated confocal features were as follows: presence of pagetoid cells, cell shape (roundish or dendritic) and number (< 5 or >5 cells per mm2), overall architecture (ringed, meshwork, clods and non‐specific pattern); architectural disorder, presence of cytological atypia (>5 cells per mm2) and cells arranged in nests. Results Among 322 lesions 70 were melanomas and 252 were nevi. According to the classification based on the 7‐point checklist score, 130 ‘featureless lesions’ (score 0–2) including six melanomas, and 102 ‘positive‐borderline’ moles (score 3–4) including 17 melanomas, were identified. Round pagetoid cells >5 cells per mm2 and/or architectural disorder on RCM were found in all of six melanomas with featureless dermoscopy. Round pagetoid infiltration and five or more atypical cells at the DEJ were found in 16 positive ‘borderline melanomas’. Conclusions RCM represents a rapid non‐invasive technique that can aid early diagnosis of dermoscopic difficult melanomas. Use of RCM on lesions with clinical and/or dermoscopic suspect of malignancy may reduce the number of unnecessary excision increasing the rate of accurate diagnoses.

Non-invasive diagnostic tools are effective in the histomorphological study of melanocytic lesions. The role of melanoma susceptibility genes on melanocytic nevi histopathological features is not clear. The current study aimed to correlate genetic alterations and histomorphological features of melanocytic nevi. Clinical, dermoscopic and confocal features of 34 multiple melanoma patients and 34 controls were compared. Among patients with melanoma, carriers of CDKN2A mutations and/or MC1R variants, and wild-type genes were also compared. In patients with melanoma, a lighter phototype (P = 0.051), a higher number of nevi (P < 0.01) and clinically atypical nevi (P < 0.01) were observed. At dermoscopy, these nevi showed a complex pattern (P = 0.011), atypical network (P = 0.018) and irregular pigmentation (P = 0.037); at confocal, an irregular meshwork pattern (P = 0.026) with atypical nests (P = 0.016) and an inflammatory infiltrate (P = 0.048) were observed. Among patients with melanoma genetically tested, CDKN2A G101W mutation carriers were more frequently younger (P = 0.023), with clinically atypical nevi (P = 0.050), with cytological atypia (P = 0.033) at confocal. G101W mutation and MC1R variants carriers showed hypopigmented nevi (P = 0.002) and, at confocal, roundish cells infiltrating the junction (P = 0.019). These data suggest an influence of CDKN2A mutation and MC1R variants in the development of dysplastic melanocytic lesions. Non-invasive histomorphological evaluation, together with genetic studies, improves melanoma risk identification and early diagnosis, for a patient-tailored management.

Reflectance confocal microscopy (RCM) is an emerging noninvasive diagnostic tool that provides in vivo tissue images at nearly cellular histological resolution. Peculiar confocal findings of melanocytic lesions have been evaluated and applied in real clinical settings to elucidate the impact of RCM in improving diagnostic accuracy. This review aims to clearly update the relevant confocal findings and to critically analyze their role in the clinical scenari