Distinct melanoma types based on reflectance confocal microscopy

Abstract

Distinct melanoma types exist in relation to patient characteristics, tumor morphology, histopathologic aspects and genetic background. A new diagnostic imaging tool, reflectance confocal microscopy (RCM), allows in vivo analysis of a given lesion with nearly histologic resolution while offering a dynamic view of the tissue in its 'natural' environment. The aim of this study was to analyse cell morphology of consecutive melanomas as they appear on RCM and to correlate morphology with tumor and patient characteristics. One hundred melanomas were visualized by RCM before excision. Clinical data, confocal features and histologic criteria were analysed. Four types of melanomas were identified as follows: (i) Melanomas with a predominantly dendritic cell population ('dendritic-cell melanomas') typically were thin by Breslow index; (ii) Melanomas typified by roundish melanocytes were smaller in size than dendritic cell MMs, but thicker by Breslow index, and predominantly occurred in patients with a high nevus count; (iii) Melanomas characterized by dermal nesting proliferation usually were thick by Breslow index at the time of diagnosis, although frequently smaller in size compared with the other types; and (iv) combined type melanomas may represent an evolution of dendritic cell and/or round cell types. Integration of confocal microscopy with clinical and histologic aspects may help in identifying and managing distinct tumors.

Association Between Confocal Morphologic Classification and Clinical Phenotypes of Multiple Primary and Familial Melanomas

“…11 These findings reinforce the hypothesis that at least 2 different routes of melanoma development exist. The first was associated with multiple nevi, predominance on the trunk, and younger age at onset, characterized via RCM by round cell pattern.…”

“…2, [6][7][8][9][10] Recently, 4 distinct melanoma phenotypes on RCM were described as follows: dendritic cell, round cell, dermal nest, and combined melanomas. 11 The authors found that melanomas with a predominant population of dendritic cells were thinner by Breslow index, and melanomas typified by roundish melanocytes or dermal nests were smaller but thicker by Breslow index. 11 The purpose of this study was to correlate morphologic RCM patterns with clinical data, genetic variants, dermoscopic features, and histologic criteria in the context of patients with multiple primary and familial melanomas.…”

Confocal microscopy characterization of BRAFV600E mutated melanomas

“…However, RCM is an important noninvasive diagnostic tool that has enabled satisfactory characterization of melanocytic and nonmelanocytic skin lesions. Numerous articles describe its utility in defining cell population and morphology in melanomas, which makes it a useful supplement to clinical and histologic findings, with which RCM shows precise correlates [10][11][12][13][14]. In addition, interestingly, it was used for the follow-up of changing moles in patients receiving treatment with BRAF inhibitors for metastatic melanomas [15].…”

“…For the evaluation of dermoscopic and confocal images, both semiquantitative evaluations and quantitative measurements were obtained. Two expert dermoscopists and confocalists evaluated six dermoscopic patterns and six RCM parameters that were selected to better characterize invasive melanomas from the wider group of known dermoscopic and RCM known descriptors (Table 1) [10]. Absolute and relative frequencies were calculated for each parameter to characterize BRAFp.V600E mutated melanomas.…”

Detection theory for accurate and non-invasive skin cancer diagnosis using dynamic thermal imaging

“…One of the critical barriers in early skin-cancer detection is the lack of reliable non-invasive techniques [7] that can detect the cancer at an early stage with high detection probability (i.e., the probability of correctly detecting a malignant lesion) and low false-alarm probability (i.e., the probability of declaring a benign lesion as malignant). Non-invasive techniques for skin-cancer detection include multispectral (MS) imaging [8][9][10], digital dermatoscopy and videodermatoscopy (sequential digital dermatoscopy) [11,12], reflectance-mode confocal microscopy [13], ultrasound [14,15], laser Doppler perfusion imaging [16], and optical coherence tomography (OCT) [17,18]. Each technology presents some restrictions and limitations to non-invasively detect skin cancer with high detection probability and low false-alarm probability.…”