Learning Reflectance Confocal Microscopy of Melanocytic Skin Lesions through Histopathologic Transversal Sections

Abstract

Histopathologic interpretation of dermoscopic and reflectance confocal microscopy (RCM) features of cutaneous melanoma was timidly carried out using perpendicular histologic sections, which does not mimic the same plane of the image achieved at both techniques (horizontal plane). The aim of this study was to describe the transverse histologic sections research technique and correlate main dermoscopic features characteristic of cutaneous melanoma (atypical network, irregular globules and pseudopods) with RCM and histopathology in perpendicular and transverse sections in order to offer a more precise interpretation of in vivo detectable features. Four melanomas and 2 nevi with different dermoscopic clues have been studied. Lesion areas that showed characteristic dermoscopic features were imaged by dermoscopy and confocal microscopy and directly correlated with histopathology in perpendicular and transverse sections. We presented the possibility to perform transverse sections as a new approach to understand RCM features. Atypical network showed different aspects in the 2 melanomas: in one case it was characterized by pleomorphic malignant melanocytes with tendency to form aggregates, whereas in the other elongated dendritic cells crowded around dermal papillae, some of them forming bridges that resembled the mitochondrial aspect at confocal and histopathology transversal sections. Pigment globules in melanomas and nevi differed for the presence of large atypical cells in the former, and pseudopods showed up as elongated nests protruded toward the periphery of the lesion. Transverse histologic research sections have a consistent dermoscopic and confocal correlate, and it may represent an help in confocal feature interpretation and an advance in improving melanoma diagnosis and knowledge of the biology of melanocytic lesions.

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

“…) strengthen the value of combined use of the two techniques in lesions with only weak clinical and/or dermoscopic clues of malignancy . Moreover, these data stress to carefully look for junctional alterations, that may be sometimes subtle, to identify early form of melanomas characterized by single‐cell proliferation that may lack of the common melanoma patterns ( 7 ), but may present characteristic clues, such as the presence of tangled filaments/dendrites crossing the papillae …”

In vivo reflectance confocal microscopy features of a melanoacanthoma

“…In hindsight, the dense, almost uniform proliferation of dendritic melanocytes at both the basal and suprabasal layers of the epidermis may be a clue to melanoacanthoma; however, this potential clue may be difficult to evaluate in cases where the basal layer is not explorable. On the other hand, previous reports of the presence of dendritic cells in RCM of melanomas were typically observed in flat lesions [21,22]. Therefore, another possible diagnostic clue for the RCM of melanoacanthoma may be the presence of dendritic cells in the context of a thickened epidermis with RCM characteristics consistent with seborrheic keratosis, including fissures and horn pseudocysts.…”

On the horizon: Optical imaging for cutaneous squamous cell carcinoma

“…Contrast‐enhancing agents both nonspecific (D) and specific (E), by means of tagging a tumor targeting specific monoclonal antibody with a fluorescent dye, have been introduced as contrast‐enhancing agents to increase the sensitivity and specificity of cancer detection. From (A) Chen et al, (B) Braga et al, (C) Hwang et al, (D) Schucht et al, and (E) Shi et al…”

“…Confocal microscopy is similar to ultrasound in that diagnostic imaging is acquired in a single plane with high, noncontrasted resolution. However, confocal microscopy utilizes optical reflectivity rather than the acoustical reflectivity implemented in ultrasound (Figure B) …”