Nodular skin lesions: correlation of reflectance confocal microscopy and optical coherence tomography features

Abstract

Background Nodular lesions have common clinical appearance but different prognoses. Differential diagnosis between melanoma (MM), basal cell carcinoma (BCC) and dermal naevus (DN) poses a challenge in clinical practice. Reflectance confocal microscopy (RCM) and optical coherence tomography (OCT) are promising non-invasive imaging techniques, potentially able to decrease redundant biopsies. RCM allows in vivo visualization of skin down to the papillary dermis at almost histological resolution, while OCT, particularly dynamic OCT (D-OCT), provides images deeper within the dermis and reveals the vascular pattern. Objectives To identify correlating features observed with RCM and OCT associated with the different nodular lesion diagnoses. Methods We retrospectively assessed 68 nodular lesions (30 MM, 20 BCC and 18 DN) with RCM and subsequently OCT.At the end of the study, evaluations were matched with histopathological diagnosis and statistical analysis was performed.Results In MM, 57% (17/30) evidenced both cerebriform nests at RCM and icicle-shaped structures at OCT, with higher average Breslow index. In 80% of BCCs with basaloid islands at RCM, OCT showed ovoid structures. More than half of DN (56%) showed hyporeflective nests at OCT and either dense nests or dense and sparse nests at RCM. ConclusionsThe combined use of RCM and OCT offers a better understanding of the morphological architecture of nodular lesions, correlating RCM parameters with OCT and vice versa, assisting in turn with early differential diagnosis of malignant and benign nodular lesions. The correlation between icicle-shaped structures and cerebriform nests in MM and their association with Breslow index requires future research.

Skin tags imaged by reflectance confocal microscopy, optical coherence tomography and multispectral optoacoustic tomography at the bedside

“…In a recent study, Garbarino et al used the combination of RCM and OCT to diagnose nodular skin lesions 18 . Interestingly, they found that epidermis icicle shape in OCT images significantly paralleled cerebriform nests in RCM images of MM 18 . In our study, the MSOT data rendering spatial distribution of melanin and vascularization indicated that all skin tags were benign, since there was no infiltration of vessels inside the melanin signal from the lesions 28 .…”

“…In a recent study, Garbarino et al used the combination of RCM and OCT to diagnose nodular skin lesions 18 . Interestingly, they found that epidermis icicle shape in OCT images significantly paralleled cerebriform nests in RCM images of MM 18 .…”

“…Optical coherence tomography (OCT) creates scanning images of skin like ultrasound but utilizes coherent light instead of sound waves. It creates images by using back‐scattered light also depending on the refractive index of the structure of interest 8,17,18 . It reaches a depth of 1‐2 mm.…”

“…It reaches a depth of 1‐2 mm. Clinical applications of OCT include diagnosis of keratinocyte carcinomas and margin delineation, monitoring of disease progression in inflammatory, infectious, blistering skin diseases, vascular lesions and wound healing 8,17,18 . Previous studies have shown characteristic vessels in BCC lesions, MM and nailfold capillaries in systemic connective tissue disease 19,20 …”

Comparative Analysis of Diagnostic Techniques for Melanoma Detection: A Systematic Review of Diagnostic Test Accuracy Studies and Meta-Analysis

“…Reliable correlates for epidermal and junctional histological features, useful for diagnostic purposes, were identifiable using RCM imaging (18,20,24,25,30). Four melanoma scoring algorithms based on these features were validated in literature (18,27,83,84).…”