Line-field confocal optical coherence tomography of sebaceous hyperplasia: a case series

Line-field confocal optical coherence tomography of lentigo maligna with horizontal and vertical histopathologic correlations

Lentigo maligna (LM) is a subtype of in situ melanoma that classically presents in elderly patients as a slowly growing lesion on sun-exposed areas that may evolve to invasive melanoma. Line-field confocal optical coherence tomography (LC-OCT) is a new non-invasive technique for a real-time, vertical, and horizontal skin imaging with high resolution close to conventional histopathology. We present the LC-OCT features of an LM of the nose in a 49-year-old white man along with their horizontal and vertical histopathological correlations. LC-OCT was able to detect in vivo, in both horizontal and vertical imaging, the main microscopic features typical of LM by showing, in the epidermis and around the hair follicles, the presence of large, bright roundish, or dendritic atypical cells, with evident nuclei, corresponding to atypical melanocytes with a tendency toward folliculotropism. A strong correspondence between LC-OCT images and vertical and horizontal histopathological sections was observed. Our study, although limited to a single case, is indicative of the great potential of LC-OCT to improve the non-invasive diagnosis of LM.

Line-field confocal optical coherence tomography: a new tool for non-invasive differential diagnosis of pustular skin disorders

Background

The spectrum of pustular skin disorders (PSD) is large and particularly challenging, including inflammatory, infectious and amicrobial diseases. Moreover, although pustules represent the unifying clinical feature, they can be absent or not fully developed in the early stage of the disease. The line‐field confocal optical coherence tomography (LC‐OCT) is a recently developed imaging technique able to perform a non‐invasive, in vivo, examination of the epidermis and upper dermis, reaching very high image resolution and virtual histology.

Objectives

We aimed to investigate the potentialities of LC‐OCT in the non‐invasive differential diagnosis of a series of 11 PSD with different aetiology, microscopic features, body location and incidence rates.

Materials and Methods

Complete LC‐OCT imaging (i.e. 2D/3D frames, videos) was performed on a total of 19 patients (10 females and 9 males) aged between 35 and 79 years. Images were blindly evaluated and compared with corresponding histopathologic findings.

Results

The LC‐OCT imaging was able to detect with high accuracy the pustule structure including shape, margins, morphology and cellular content, along with peculiar epidermal and adnexal alterations in each condition, including: Acute Generalized Exanthematous Pustulosis, Generalized pustular psoriasis, Generalized pustular figurate erythema, Subcorneal Pustular Dermatosis, Intraepidermal IgA pustulosis, Palmoplantar pustulosis, Palmoplantar pustular psoriasis. Herpetic whitlow, Acrodermatitis continua of Hallopeau, Vesicopustular Sweet syndrome and Vesicopustular Eosinophilic cellulitis, with pustular appearance, were also compared.

Conclusions

The new LC‐OCT can represent a rapid, non‐invasive and painless tool which can help differentiating among PSD of different aetiology and microscopic morphology in clinical mimickers in daily practice.

Line-field confocal optical coherence tomography of psoriasis, eczema and lichen planus: a case series with histopathological correlation

BACKGROUND

Line-field confocal optical coherence tomography (LC-OCT) is a novel, non-invasive technique that provides in vivo, high-resolution images in both vertical and horizontal sections.

OBJECTIVES

The aim of the study was to evaluate LC-OCT imaging in some inflammatory disorders and to correlate the resulting features with histopathology.

METHODS

The retrospective study included patients with histopathological confirmed diagnosis of plaque psoriasis, atopic eczema and lichen planus, who were imaged with LC-OCT before the biopsy. LC-OCT was performed with the commercially available LC-OCT device.

RESULTS

A total of 15 adult patients with histopathologically proven plaque psoriasis (N: 5), atopic eczema (N: 5) and lichen planus (N: 5) were included. In all cases, LC-OCT allowed the in vivo recognition of the main microscopic features of the examined inflammatory skin disease, with a strong correlation with histopathology.

CONCLUSIONS

Although future studies on larger series of patients are necessary, LC-OCT, based on these preliminary findings, may represent a promising tool in inflammatory skin disorders with potential applications including enhanced diagnosis, biopsy guidance, follow-up and treatment monitoring.

Line-Field Confocal Optical Coherence Tomography: A New Tool for the Differentiation between Nevi and Melanomas?

Until now, the clinical differentiation between a nevus and a melanoma is still challenging in some cases. Line-field confocal optical coherence tomography (LC-OCT) is a new tool with the aim to change that. The aim of the study was to evaluate LC-OCT for the discrimination between nevi and melanomas. A total of 84 melanocytic lesions were examined with LC-OCT and 36 were also imaged with RCM. The observers recorded the diagnoses, and the presence or absence of the 18 most common imaging parameters for melanocytic lesions, nevi, and melanomas in the LC-OCT images. Their confidence in diagnosis and the image quality of LC-OCT and RCM were evaluated. The most useful criteria, the sensitivity and specificity of LC-OCT vs. RCM vs. histology, to differentiate a (dysplastic) nevus from a melanoma were analyzed. Good image quality correlated with better diagnostic performance (Spearman correlation: 0.4). LC-OCT had a 93% sensitivity and 100% specificity compared to RCM (93% sensitivity, 95% specificity) for diagnosing a melanoma (vs. all types of nevi). No difference in performance between RCM and LC-OCT was observed (McNemar's p value = 1). Both devices falsely diagnosed dysplastic nevi as non-dysplastic (43% sensitivity for dysplastic nevus diagnosis). The most significant criteria for diagnosing a melanoma with LC-OCT were irregular honeycombed patterns (92% occurrence rate; 31.7 odds ratio (OR)), the presence of pagetoid spread (89% occurrence rate; 23.6 OR) and the absence of dermal nests (23% occurrence rate, 0.02 OR). In conclusion LC-OCT is useful for the discrimination between melanomas and nevi.

Line-Field Confocal Optical Coherence Tomography Increases the Diagnostic Accuracy and Confidence for Basal Cell Carcinoma in Equivocal Lesions: A Prospective Study

Simple Summary

Basal cell carcinoma is the most frequently occurring type of skin cancer. Its treatment can be either local or surgical depending on its subtype and extension, with early recognized and superficial cases being easier to treat. Some of them, however, display unspecific features, making diagnosis difficult. Non-invasive devices such as line-field confocal optical coherence tomography (LC-OCT) are able to recognize morphological features of different BCC subtypes with a good correlation to histopathology. We decided to study their application to clinically doubtful BCC cases.

Abstract

Diagnosing clinically unclear basal cell carcinomas (BCCs) can be challenging. Line-field confocal optical coherence tomography (LC-OCT) is able to display morphological features of BCC subtypes with good histological correlation. The aim of this study was to investigate the accuracy of LC-OCT in diagnosing clinically unsure cases of BCC compared to dermoscopy alone and in distinguishing between superficial BCCs and other BCC subtypes. Moreover, we addressed pitfalls in false positive cases. We prospectively enrolled 182 lesions of 154 patients, referred to our department to confirm or to rule out the diagnosis of BCC. Dermoscopy and LC-OCT images were evaluated by two experts independently. Image quality, LC-OCT patterns and criteria, diagnosis, BCC subtype, and diagnostic confidence were assessed. Sensitivity and specificity of additional LC-OCT were compared to dermoscopy alone for identifying BCC in clinically unclear lesions. In addition, key LC-OCT features to distinguish between BCCs and non-BCCs and to differentiate superficial BCCs from other BCC subtypes were determined by linear regressions. Diagnostic confidence was rated as “high” in only 48% of the lesions with dermoscopy alone compared to 70% with LC-OCT. LC-OCT showed a high sensitivity (98%) and specificity (80%) compared to histology, and these were even higher (100% sensitivity and 97% specificity) in the subgroup of lesions with high diagnostic confidence. Interobserver agreement was nearly perfect (95%). The combination of dermoscopy and LC-OCT reached a sensitivity of 100% and specificity of 81.2% in all cases and increased to sensitivity of 100% and specificity of 94.9% in cases with a high diagnostic confidence. The performance of LC-OCT was influenced by the image quality but not by the anatomical location of the lesion. The most specific morphological LC-OCT criteria in BCCs compared to non-BCCs were: less defined dermoepidermal junction (DEJ), hyporeflective tumor lobules, and dark rim. The most relevant features of the subgroup of superficial BCCs (sBCCs) were: string of pearls pattern and absence of epidermal thinning. Our diagnostic confidence, sensitivity, and specificity in detecting BCCs in the context of clinically equivocal lesions significantly improved using LC-OCT in comparison to dermoscopy only. Operator training for image acquisition is fundamental to achieve the best results. Not only the differential diagnosis of BCC, but also BCC subtyping can be performed at bedside with LC-OCT.

Line-field confocal optical coherence tomography as a tool for three-dimensional in vivo quantification of healthy epidermis: A pilot study

Epidermal three-dimensional (3D) topography/quantification has not been completely characterized yet. The recently developed line-field confocal optical coherence tomography (LC-OCT) provides real-time, high-resolution, in-vivo 3D imaging of the skin. This pilot study aimed at quantifying epidermal metrics (epidermal thicknesses, dermal-epidermal junction [DEJ] undulation and keratinocyte number/shape/size) using 3D LC-OCT. For each study participant (8 female, skin-type-II, younger/older volunteers), seven body sites were imaged with LC-OCT. Epidermal metrics were calculated by segmentations and measurements assisted by artificial intelligence (AI) when appropriate. Thicknesses of epidermis/SC, DEJ undulation and keratinocyte nuclei volume varied across body sites. Evidence of keratinocyte maturation was observed in vivo: keratinocyte nuclei being small/spherical near the DEJ and flatter/elliptical near the skin surface. Skin microanatomy can be quantified by combining LC-OCT and AI. This technology could be highly relevant to understand aging processes and conditions linked to epidermal disorders. Future clinical/research applications are to be expected in this scenario.

Line-Field Confocal Optical Coherence Tomography May Enhance Monitoring of Superficial Basal Cell Carcinoma Treated with Imiquimod 5% Cream: A Pilot Study

Line-field confocal optical coherence tomography (LC-OCT) is a novel, non-invasive technique for real-time skin imaging. Imiquimod (IQ) 5% cream is an immune response modifier currently approved for the treatment of small, superficial basal cell carcinoma (BCC). The aim of this study was to investigate if LC-OCT may be useful to enhance the treatment monitoring of BCC. Twenty superficial BCCs from 12 patients were treated with IQ 5% cream once daily, five days a week, for six weeks. Clinical and LC-OCT evaluations were performed at baseline and 4 weeks after the end of treatment. At the end of the study, 13 lesions showed a complete clinical and LC-OCT response, 4 lesions a partial clinical and LC-OCT response, and 3 lesions a complete clinical response but residual tumoral signs at LC-OCT. Our pilot study suggests that LC-OCT may represent a promising tool able to enhance the evaluation of the treatment response of BCCs to non-invasive treatments. In our case series, its use highlighted, through a detailed, fast, and complete examination of the treated area, three cases of residual BCC that otherwise would have gone undetected at clinical examination. Future studies on larger series of patients treated with different modalities and with a longer follow-up are advisable.