Dermoscopic difficult lesions: an objective evaluation of reflectance confocal microscopy impact for accurate diagnosis

Abstract

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.

Discriminating Nevi from Melanomas

“…In contrast, only 17.7% (n = 30) of nevi were incorrectly diagnosed as melanoma (false positive). 30 In addition, RCM was also found to be helpful in evaluating small-diameter (ie, incipient melanomas) melanomas. 31 With RCM, the combination of cytologic atypia with cellular pleomorphism and architectural disorder with irregular clods was found to be strong criteria for the identification of incipient melanomas.…”

Lesions Mimicking Melanoma at Dermoscopy Confirmed Basal Cell Carcinoma: Evaluation with Reflectance Confocal Microscopy

“…RCM may be especially helpful in difficult lesions, where clinical and dermoscopic features are not straightforward[14-17]. …”

Combined in vivo reflectance confocal microscopy and digital dermoscopy for follow up of patients at high risk of malignant melanoma: A prospective case series study

“…Several studies have consistently suggested that the addition of RCM to dermoscopy decreases the "number needed to treat" 19,20,29 and patient management costs. Two recent studies 2,19 evaluated the use of RCM in combination with digital dermoscopy in a very similar clinical setting to that described here, and found that the combination of these two diagnostic tools could have prevented the excision of 27 of 58 and 35 of 51 nevi, respectively, a proportion very similar to that reported in the present series (46/87).…”