Management of clinical and subclinical actinic keratoses with histological and immunohistochemical assessments by confocal microscopy

In Vivo Imaging Techniques for the Human Scalp: A Systematic Review of the Literature

OBJECTIVE

Scalp inflammation and alopecia are distressing conditions for which patients regularly present to dermatology. Although some diagnoses can be made clinically, others require biopsy, which carries the risk of pain, infection, bleeding, and scarring. This review examines the existing literature regarding noninvasive in vivo imaging techniques and their evidence and utility in evaluating scalp pathology, with a focus on the diagnostics of hair conditions.

METHODS

A systematic literature search was conducted using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines without timeframe restrictions. The PubMed and Clarivate (Web of Science) databases were searched using the terms ("imaging" OR "in-vivo imaging" OR "non-invasive imaging" OR "non-invasive in vivo imaging" "imaging," "in-vivo imaging) AND ("human scalp disorders" OR "scalp" OR "hair loss" OR "alopecia"). Peer-reviewed randomized control trials (RCTs), prospective studies, retrospective studies, and case series or reports discussing in vivo imaging of the scalp published before 2022 were selected.

RESULTS

Forty-two studies were included and discussed; modalities included laser devices (n = 27), ultrasound (US) (n = 13), infrared thermography (n = 1), skin capacitance imaging (SCI), and ultraviolet light-enhanced visualization (ULEV) (n = 1). The most common laser devices used were reflectance confocal microscopy (RCM), multiphoton microscopy (MPM), and optical coherence tomography (OCT). US techniques included high-frequency US (HFUS) and US biomicroscopy (UBM).

CONCLUSION

Quality imaging of the scalp in the setting of alopecic, neoplastic, and inflammatory diseases is highly sought after. Many of these noninvasive imaging techniques show promise, each with individual advantages and disadvantages in imaging-specific conditions. Ultimately, noninvasive imaging techniques may be used to optimize patient management and minimize morbidity associated with scalp biopsies.

Systematic review of randomized controlled trials of topicals for actinic keratosis field therapy

Cutaneous field cancerization in dermatology describes the anatomic region of photodamaged skin with actinic keratoses (AKs) or cutaneous squamous cell carcinoma (cSCC) that is surrounded by cellular atypia, forming a dysplastic field. The concept of field cancerization is especially relevant in dermatology, as actinic keratoses and the surrounding dysplastic region can progress to carcinomas, necessitating the treatment of the field. Recent research has focused on field-directed therapy using topical agents. This study aims to systematically review randomized controlled trials on topical treatments for actinic keratosis field cancerization, following the PRISMA guidelines. Clinical recommendations were based on the Oxford Centre for Evidence-Based Medicine. We identified 20 original randomized controlled trials for topical cutaneous field therapy. 0.5% 5-Fluorouracil/salicylic acid and 0.5% 5-fluorouracil received a clinical recommendation grade of A, while diclofenac sodium received a clinical recommendation grade of B. Calcipotriol/5-fluorouracil, Imiquimod, sunscreen combination therapies, and tirbanibulin received a recommendation grade of C. This review provides a framework for clinicians when considering topical treatments for patients with field cancerization.

An Actinic Keratosis Auxiliary Diagnosis Method Based on an Enhanced MobileNet Model

Actinic keratosis (AK) is a common precancerous skin lesion with significant harm, and it is often confused with non-actinic keratoses (NAK). At present, the diagnosis of AK mainly depends on clinical experience and histopathology. Due to the high difficulty of diagnosis and easy confusion with other diseases, this article aims to develop a convolutional neural network that can efficiently, accurately, and automatically diagnose AK. This article improves the MobileNet model and uses the AK and NAK images in the HAM10000 dataset for training and testing after data preprocessing, and we performed external independent testing using a separate dataset to validate our preprocessing approach and to demonstrate the performance and generalization capability of our model. It further compares common deep learning models in the field of skin diseases (including the original MobileNet, ResNet, GoogleNet, EfficientNet, and Xception). The results show that the improved MobileNet has achieved 0.9265 in accuracy and 0.97 in Area Under the ROC Curve (AUC), which is the best among the comparison models. At the same time, it has the shortest training time, and the total time of five-fold cross-validation on local devices only takes 821.7 s. Local experiments show that the method proposed in this article has high accuracy and stability in diagnosing AK. Our method will help doctors diagnose AK more efficiently and accurately, allowing patients to receive timely diagnosis and treatment.

In Vivo Reflectance Confocal Microscopy as a Response Monitoring Tool for Actinic Keratoses Undergoing Cryotherapy and Photodynamic Therapy

Simple Summary

The assessment of actinic keratoses (AKs) in prevention and therapeutic trials, as well as clinical practice, could significantly benefit from the incorporation of non-invasive imaging technology. Such technology has the potential to enhance the objective evaluation of clinical and subclinical AKs with the added advantage of sequential monitoring. In vivo reflectance confocal microscopy (RCM) allows for the non-invasive imaging of AKs at a cellular level. We aimed to establish an in in vivo RCM protocol for AK response monitoring, ultimately leading to more reliable characterization of longitudinal responses and therapy optimization.

Abstract

Reflectance confocal microscopy (RCM) presents a non-invasive method to image actinic keratosis (AK) at a cellular level. However, RCM criteria for AK response monitoring vary across studies and a universal, standardized approach is lacking. We aimed to identify reliable AK response criteria and to compare the clinical and RCM evaluation of responses across AK severity grades. Twenty patients were included and randomized to receive either cryotherapy (n = 10) or PDT (n = 10). Clinical assessment and RCM evaluation of 12 criteria were performed in AK lesions and photodamaged skin at baseline, 3 and 6 months. We identified the RCM criteria that reliably characterize AK at baseline and display significant reduction following treatment. Those with the highest baseline odds ratio (OR), good interobserver agreement, and most significant change over time were atypical honeycomb pattern (OR: 12.7, CI: 5.7–28.1), hyperkeratosis (OR: 13.6, CI: 5.3–34.9), stratum corneum disruption (OR: 7.8, CI: 3.5–17.3), and disarranged epidermal pattern (OR: 6.5, CI: 2.9–14.8). Clinical evaluation demonstrated a significant treatment response without relapse. However, in grade 2 AK, 10/12 RCM parameters increased from 3 to 6 months, which suggested early subclinical recurrence detection by RCM. Incorporating standardized RCM protocols for the assessment of AK may enable a more meaningful comparison across clinical trials, while allowing for the early detection of relapses and evaluation of biological responses to therapy over time.

AK-DL: A Shallow Neural Network Model for Diagnosing Actinic Keratosis with Better Performance Than Deep Neural Networks

Actinic keratosis (AK) is one of the most common precancerous skin lesions, which is easily confused with benign keratosis (BK). At present, the diagnosis of AK mainly depends on histopathological examination, and ignorance can easily occur in the early stage, thus missing the opportunity for treatment. In this study, we designed a shallow convolutional neural network (CNN) named actinic keratosis deep learning (AK-DL) and further developed an intelligent diagnostic system for AK based on the iOS platform. After data preprocessing, the AK-DL model was trained and tested with AK and BK images from dataset HAM10000. We further compared it with mainstream deep CNN models, such as AlexNet, GoogLeNet, and ResNet, as well as traditional medical image processing algorithms. Our results showed that the performance of AK-DL was better than the mainstream deep CNN models and traditional medical image processing algorithms based on the AK dataset. The recognition accuracy of AK-DL was 0.925, the area under the receiver operating characteristic curve (AUC) was 0.887, and the training time was only 123.0 s. An iOS app of intelligent diagnostic system was developed based on the AK-DL model for accurate and automatic diagnosis of AK. Our results indicate that it is better to employ a shallow CNN in the recognition of AK.

Prise en charge thérapeutique des kératoses actiniques

Dermatologists have many therapeutic options for the management of actinic keratoses (AK), in order to treat individual lesions or wider areas. Field cancerization is an area of sun-damaged skin, where visible and subclinical lesions co-exist, and is prone to the development of further AK lesions and sun-related skin cancers (SC). Treatments available are instrumental or medical. Resistance to treatment or atypical symptoms must lead to a biopsy for histological exam. Cryotherapy is the most frequently used method to destroy small or isolated AK, whereas photodynamic therapy (PDT), 5-fluoro-uracil (5-FU), imiquimod, ingenol mebutate and diclofenac are required for large, multiple lesions, and for the treatment of field cancerization. Side-effects of these therapies are essentially local, including pain, irritation, erythema, edema and scars. There is no randomized comparative study reviewing all these treatments, therefore physicians must also consider clinical characteristics, patient's compliance, side-effects and cost when treating AK. Medicoeconomic data of these treatments have been analyzed in several countries, and annual costs are estimated between 250 € and 2 000 €, with an uncertain cost-effective relation. Finally, beyond treatment of AK lesions, patients with AK are at high risk of developing SC, and must therefore have regular full-body examination, in order to be detected and treated precociously. © 2019 Elsevier Masson SAS. All rights reserved. Cet article fait partie du numéro supplément Kératoses actiniques : comprendre et traiter réalisé avec le soutien institutionnel de Galderma International.