Morphological evaluation of melanocytic lesions with three-dimensional line-field confocal optical coherence tomography: correlation with histopathology and reflectance confocal microscopy. A pilot study

Abstract

Background Line‐field confocal optical coherence tomography (LC‐OCT) is a new in vivo emerging technique that provides cellular resolution, allows deep imaging (400 μm) and produces real‐time images in both the horizontal and vertical plane and in three dimensions. No previous description of different subtypes of melanocytic lesions and their correlation with histopathology and reflectance confocal microscopy has been reported. Aim To describe the features of melanocytic lesions by LC‐OCT and their correlation with histopathology and reflectance confocal microscopy (RCM) findings. Methods Selected melanocytic benign lesions and melanomas were imaged in vivo with RCM and LC‐OCT at the Fundación Hospital Clinic (Barcelona, Spain). A minimum area of 4 × 4 mm (block image) at four depths (stratum granulosum, suprabasal, layer dermoepidermal junction and upper dermis) were acquired with RCM and a minimum of three cubes with LC‐OCT. Horizontal, vertical sections and three‐dimensional (3D) cubes of LC‐OCT were matched with RCM (Vivablock two‐dimensional composite mosaic) and histopathology, with ~5 μm lateral resolution accuracy (the same cell nuclei were measured in X, Y and Z) and evaluated by three observers experienced in using RCM and histopathology. Results In total, 12 melanocytic tumours (2 in situ melanomas, 2 invasive melanomas, 4 atypical naevi, 2 intradermal naevi, 1 compound naevus and 1 junctional naevus) were included. High correlation with 5 μm accuracy between RCM and LC‐OCT was observed for each tumour. The 3D images of melanocytic lesions were obtained with cellular resolution and correlated with both RCM and histopathology, allowing an understanding of the architecture and precise correlation at the cellular level with RCM. Similarities between LC‐OCT and RCM for the described diagnostic features and architecture (nests of melanocytic cells, ringed and meshwork pattern, and cellular details of tumour cells as dendritic and pagetoid cells) were confirmed. The main advantage of diagnosis by RCM fixed probe was the ability to produce larger scans of the lesion using mosaicing compared with an LC‐OCT handheld probe. Conclusion LC‐OCT allows the architectural and cellular description of different types of melanocytic lesions. LC‐OCT showed high correlation with histopathology (vertical sections) and RCM (horizontal sections) in melanocytic lesions. Diagnostic criteria for RCM were similar to those for LC‐OCT.

Line‐field confocal optical coherence tomography of cutaneous vascular lesions: Morphological assessment and histopathological correlations

“…in children), as recently suggested. 7,19 F I G U R E 1 Dermoscopy, monodimensional LC-OCT, 3D LC-OCT and histopathology of vascular lesions: (a) red lacunae characterizing dermoscopy of cherry hemangioma; (b, c) with LC-OCT dark circular and oval-shaped spaces (red asterisks) producing a lobular architecture, due to the presence of (d) enlarged interconnecting capillaries with surrounding scant stroma at histhopathology; (e) angiokeratoma showing dermoscopic red-dark lacunae and blue whitish veil; (f, g) upon LC-OCT broadened epidermis and stratum corneum (yellow asterisk) and large dark areas protruding deeper in the dermis (red asterisks), reflecting (h) hyperkeratosis and dilated vascular channels in pathological specimen; (i) dermoscopy of thrombosed hemangioma exhibiting a jet-black area; (j, k) dark circular areas with bright amorphous material at LC-OCT (red asterisks) consistent with (l) dilated and partially thrombosed vessels on histopathology; (m) pyogenic granuloma exhibiting dermoscopic features of homogeneous reddish zones outlined by white rail lines and peripheral collarette; (n, o) LC-OCT features of linear narrow dark spaces (red arrows) and diffuse bright dots (red squares), as related to (p) multiple capillaries and inflammatory infiltrate on histopathology.…”

“…Line‐field confocal optical coherence tomography (LC‐OCT) is a new, non‐invasive system for skin assessment able to combine the technical advantages of RCM (axial resolution ≅ 1.1 μm, lateral resolution ≅ 1.3 μm) and conventional OCT (penetration depth ≅ 500 μm) 5 . Its application in dermatology is rapidly expanding, as morphological findings of neoplastic, inflammatory and infectious diseases are being progressively reported 6–11 . The aim of this study was to describe the LC‐OCT features of the most common benign and malignant VLs and to correlate them with histopathological substrates.…”

Optical coherence tomography confirms non‐malignant pigmented lesions in phacomatosis pigmentokeratotica using a support vector machine learning algorithm

“…40 LC-OCT, with its confocal capabilities, has demonstrated success at identifying melanocytic lesions with higher accuracy. 41 RCM has also demonstrated adequate sensitivity (93.5%) and specificity (78.8%) for melanoma diagnosis, 42 but the device has mostly been implemented in large hospitals and academic and research centers. 43 FF-OCT acquires images en face, and while it has been used to identify different skin tumors, it does not appear to have been applied to identification of melanoma in situ (MIS).…”

Line‐field confocal optical coherence tomography of seborrheic keratosis: A case series

“…There should not be any large, pleomorphic and irregularly shaped bright cells in the epidermis or underneath, which would be suspicious of an atypical melanocytic lesion. 8 On the other hand, SCC can be easily ruled out by the absence of keratinocyte pleomorphism in the epidermis 3 and BCC by the absence of lobular structures appended to the epidermis or located in the dermis, characterized by palisading as well as the typical millefeuille pattern (Figure 2). 4 RCM has long been used to analyse skin lesions including SK mostly in order to differentiate it from atypical melanocytic lesions.…”