Skin Imaging Using Ultrasound Imaging, Optical Coherence Tomography, Confocal Microscopy, and Two-Photon Microscopy in Cutaneous Oncology

With the recognition of dermoscopy as a new medical technology and its available fee assessment in Korea comes an increased interest in imaging-based dermatological diagnosis. For the dermatologist, who treats benign tumors and malignant skin cancers, imaging-based evaluations can assist with determining the surgical method and future follow-up plans. The identification of the tumor's location and the existence of blood vessels can guide safe treatment and enable the use of minimal incisions. The recent development of high-resolution microscopy based on laser reflection has enabled observation of the skin at the cellular level. Despite the limitation of a shallow imaging depth, non-invasive light-based histopathologic examinations are being investigated as a rapid and pain-free process that would be appreciated by patients and feature reduced time from consultation to treatment. In the United States, the current procedural terminology billing code was established for reflectance confocal microscopy in 2016 and has been used for the skin cancer diagnosis ever since. In this review, we introduce the basic concepts and images of ultrasound imaging, optical coherence tomography, confocal microscopy, and two-photon microscopy and discuss how they can be utilized in the field of dermatological oncology.ope

Complications from Cosmetic Procedures Performed by Non-Professionals: A Case Analysis and Review of Treatments

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Artificial Intelligence in Cutaneous Oncology

Skin cancer, previously known to be a common disease in Western countries, is becoming more common in Asian countries. Skin cancer differs from other carcinomas in that it is visible to our eyes. Although skin biopsy is essential for the diagnosis of skin cancer, decisions regarding whether or not to conduct a biopsy are made by an experienced dermatologist. From this perspective, it is easy to obtain and store photos using a smartphone, and artificial intelligence technologies developed to analyze these photos can represent a useful tool to complement the dermatologist's knowledge. In addition, the universal use of dermoscopy, which allows for non-invasive inspection of the upper dermal level of skin lesions with a usual 10-fold magnification, adds to the image storage and analysis techniques, foreshadowing breakthroughs in skin cancer diagnosis. Current problems include the inaccuracy of the available technology and resulting legal liabilities. This paper presents a comprehensive review of the clinical applications of artificial intelligence and a discussion on how it can be implemented in the field of cutaneous oncology.ope

Pathogenesis and prevention of skin cancer

The incidence of skin cancer has continuously increased in Korea, probably due to sun exposure and increases in the aging population. Ultraviolet light, a well-known risk factor for skin cancer, can cause DNA damage, mutation, and immune suppression, followed by abnormal proliferation. To prevent photocarcinogenesis, the appropriate use of sunscreen should be emphasized. Using broad-spectrum sunscreens with sun protection factor values of 15 or higher and frequent reapplication are recommended. Controversy exists about whether vitamin D synthesis is inhibited by the use of sunscreen. However, considering that skin cancer most commonly develops on the head and neck area, applying it to the face and neck is reasonable in terms of balancing the risk-benefit ratio.ope

Surgical Treatment of 846 Patients with Benign Skin Tumors: Experience of a Dermatologic Surgeon in Korea

Background: The incidence of skin tumors has been increasing over the past few years due to an aging population, environmental changes, and improved access to medical institutions. Objective: To report the rate of relapse and complications after surgical treatment, and suggest appropriate ways of treating benign skin tumors. Methods: We performed a retrospective review of 846 patients with benign skin tumors who were diagnosed and treated by a single dermatosurgeon. Results: Of the 846 patients, 18 (2.1%) developed local recurrence. Epidermal cysts (15/390) were the most common skin condition, followed by lipomas (2/149). The recurrence rate of epidermal cysts showed no statistical difference when treatment options and the presence of inflammation or suppuration at the first visit were considered. Six patients (0.7%, 6/846) had one of the complications such as persistent inflammation over one month, severe pain, secondary infection, or skin necrosis. All the lipomas following recurrence or those with complications were located in the intramuscular or submuscular area of the forehead, which were easily localized by sonography. Conclusion: Surgery is a valuable method for the treatment of benign skin tumors with low rates of complication and relapse. For better outcomes after treatment, dermatologists should attempt to remove these tumors completely and consider the use of imaging studies before treatment.ope

High-speed combined reflectance confocal and moxifloxacin based two-photon microscopy

Reflectance confocal microscopy (RCM) is a non-invasive high-resolution optical imaging technique used in clinical settings as a diagnostic method. However, RCM has limited diagnostic ability by providing non-specific morphological information only based on reflection contrast. Various multimodal imaging techniques have been developed to compensate the limitations of RCM, but multimodal techniques are often slow in imaging speed compared to RCM alone. In this report, we combined RCM with moxifloxacin based two-photon microscopy (TPM) for high-speed multimodal imaging. Moxifloxacin based TPM used clinically compatible moxifloxacin for cell labeling and could do non-invasive cellular imaging at 30 frames/s together with RCM. Performance of the combined microscopy was characterized in the imaging of mouse skin and cornea, in vivo. Detail tissue microstructures including cells, extra-cellular matrix (ECM), and vasculature were visualized. The combined microscopy was applied to human skin cancer specimens, and both cells and ECM in the skin cancer and normal skin regions were visualized at high imaging speeds. The combined microscopy can be useful in the clinical applications of RCM by providing multiple contrasts.ope

Pre-Processing for Determining Acral Lentiginous Melanoma(ALM)

Melanoma is originated from the melanocyte producing the melanin which determines the complexion,and it has the highest mortality among skin cancers. Acral lentiginous melanoma(ALM) arises from extremities suchas hands, feet or fingernails. Since the appearance of ALM is different from melanoma on the body, conventional autodiagnosis systems for melanoma is inappropriate to detect ALM. Therefore, ALM is typically difficult to distinguishfrom general nevus, resulting in delayed diagnosis and bad prognosis. In this paper, we firstly introduce a determinationmethod for ALM by dermatologists and propose a method to rotate dermoscopic images automatically asa pre-processing for facilitating the easy determination of ALM and to select the optimal value of the Gaussian differentiationfilter parameter which is significant for precise pattern extraction using the scale space analysis. Fromexperimental results, it is shown that there exists the consistency between empirical values of the Gaussian differentialfilter parameter and optimal values derived from the scale space analysis to distinguish nevus and ALM.ope

Acral melanoma detection using a convolutional neural network for dermoscopy images

BACKGROUND/PURPOSE: Acral melanoma is the most common type of melanoma in Asians, and usually results in a poor prognosis due to late diagnosis. We applied a convolutional neural network to dermoscopy images of acral melanoma and benign nevi on the hands and feet and evaluated its usefulness for the early diagnosis of these conditions. METHODS: A total of 724 dermoscopy images comprising acral melanoma (350 images from 81 patients) and benign nevi (374 images from 194 patients), and confirmed by histopathological examination, were analyzed in this study. To perform the 2-fold cross validation, we split them into two mutually exclusive subsets: half of the total image dataset was selected for training and the rest for testing, and we calculated the accuracy of diagnosis comparing it with the dermatologist's and non-expert's evaluation. RESULTS: The accuracy (percentage of true positive and true negative from all images) of the convolutional neural network was 83.51% and 80.23%, which was higher than the non-expert's evaluation (67.84%, 62.71%) and close to that of the expert (81.08%, 81.64%). Moreover, the convolutional neural network showed area-under-the-curve values like 0.8, 0.84 and Youden's index like 0.6795, 0.6073, which were similar score with the expert. CONCLUSION: Although further data analysis is necessary to improve their accuracy, convolutional neural networks would be helpful to detect acral melanoma from dermoscopy images of the hands and feet.ope

Dermoscopy guided dark-field multi-functional optical coherence tomography

Dermoscopy is a skin surface microscopic technique allowing specular reflection free observation of the skin, and has been used to examine pigmented skin lesions. However, dermoscopy has limitations in providing depth information due to lack of 3D resolution. In order to overcome the limitations, we developed dermoscopy guided multi-functional optical coherence tomography (MF-OCT) providing both high-contrast superficial information and depth-resolved structural, birefringent, and vascular information of the skin simultaneously. Dermoscopy and MF-OCT were combined by using a dichroic mirror, and dark-field configuration was adapted for MF-OCT to reduce specular reflection. After characterization, dermoscopy guided MF-OCT was applied to several human skin lesions such as the scar, port-wine stain (PWS) as well as the normal skin for demonstration. Various features of the scar and PWS were elucidated by both dermoscopy and MF-OCT. Dermoscopy guided MF-OCT may be useful for evaluation and treatment monitoring of skin lesions in clinical applications.ope

Delayed Reconstruction for the Non-Amputative Treatment of Subungual Melanoma

BACKGROUND: In cases of early stage subungual melanoma (SUM), conservative treatment with non-amputative wide excision of the nail unit and subsequent skin graft is preferred over amputation to preserve the involved digit. OBJECTIVE: We report a series of patients with SUM treated with conservative surgery and suggest an effective supplementary treatment process. METHODS: We retrospectively reviewed 10 patients (2 males, 8 females) who were diagnosed with in situ or minimally invasive SUM on the first biopsy and underwent non-amputative wide excision of the nail unit. All patients underwent secondary intention healing during the histopathological re-evaluation of the entire excised lesion, and additional treatment was administered according to the final report. RESULTS: In two of 10 patients, amputation was performed because of the detection of deep invasion (Breslow thickness: 4.0, 2.3 mm) from the final pathologic results, which differed from the initial biopsy. In six patients who received delayed skin graft, the mean total time required for complete healing after secondary intention healing and the skin graft was 66.83±15.09 days. As a result of this delayed skin graft, the final scarring was similar to the original shape of the nail unit, scored between 5 and 10 on a visual analogue scale. Most patients were satisfied with this conservative surgery except one patient, who had volar portion involvement and received an interpolated flap instead of a skin graft. CONCLUSION: Our treatment process can reduce the risk of incomplete resection and improve cosmetic outcomes in patients with SUM.ope