Classification of Non-tumorous Facial Pigmentation Disorders Using Generative Adversarial Networks and Improved SMOTE.

The diagnosis of non-tumorous facial pigmentation disorders is crucial since facial pigmentations can serve as a health indicator for other more serious diseases. The computer-based classification of non-tumorous facial pigmentation disorders using images / photographs allows automated diagnosis of such disorders. However, the classification performance of existing methods is still not satisfactory due to the limited real-world images available for research. In this paper, we proposed a novel approach to applying generative adversarial network (GAN) with improved synthetic minority over-sampling technique (Improved SMOTE) to enhance the image dataset with more varieties. With the application of Improved SMOTE, more data is provided to train GAN models. By utilizing the GAN to perform data augmentation, more diverse and effective training images can be generated for developing classification model using deep neural networks via transfer learning. A significant increase in the classification accuracy (>4%) was achieved by the proposed method compared to the state-of-the-art method.

Melanogenesis Inhibitors.

Abnormally high production of melanin or melanogenesis in skin melanocytes results in hyperpigmentation disorders, such as melasma, senile lentigines or freckles. These hyperpigmentary skin disorders can significantly impact an individual's appearance, and may cause emotional and psychological distress and reduced quality of life. A large number of melanogenesis inhibitors have been developed, but most have unwanted side-effects. Further research is needed to better understand the mechanisms of hyperpigmentary skin disorders and to develop potent and safe inhibitors of melanogenesis. This review summarizes the current understanding of melanogenesis regulatory pathways, the potential involvement of the immune system, various drugs in current use, and emerging treatment strategies to suppress melanogenesis.

Classification of non-tumorous skin pigmentation disorders using voting based probabilistic linear discriminant analysis.

Non-tumorous skin pigmentation disorders can have a huge negative emotional impact on patients. The correct diagnosis of these disorders is essential for proper treatments to be instituted. In this paper, we present a computerized method for classifying five non-tumorous skin pigmentation disorders (i.e., freckles, lentigines, Hori's nevus, melasma and nevus of Ota) based on probabilistic linear discriminant analysis (PLDA). To address the large within-class variance problem with pigmentation images, a voting based PLDA (V-PLDA) approach is proposed. The proposed V-PLDA method is tested on a dataset that contains 150 real-world images taken from patients. It is shown that the proposed V-PLDA method obtains significantly higher classification accuracy (4% or more with p< 0.001 in the analysis of variance (ANOVA) test) than the original PLDA method, as well as several state-of-the-art image classification methods. To the authors' best knowledge, this is the first study that focuses on the non-tumorous skin pigmentation image classification problem. Therefore, this paper could provide a benchmark for subsequent research on this topic. Additionally, the proposed V-PLDA method demonstrates promising performance in clinical applications related to skin pigmentation disorders.

A retrospective clinico-pathological study comparing lichen planus pigmentosus with ashy dermatosis.

BACKGROUND/OBJECTIVES: Controversy persists as to whether lichen planus pigmentosus and ashy dermatosis are separate clinical entities. This study was conducted to examine the clinicopathological features and treatment outcome of the two conditions. METHODS: A retrospective medical chart review of all patients who were diagnosed with lichen planus pigmentosus or ashy dermatosis was conducted. The information collected included the participants' age at onset, site of onset, duration of disease, presence of precipitating factors, distribution of disease, pigmentation and presence of symptoms. In patients from whom a biopsy was taken the histopathological reports were included. RESULTS: Altogether 26 patients with ashy dermatosis and 29 with lichen planus pigmentosus were included in the study. Compared with ashy dermatosis, lichen planus pigmentosus had a more localised distribution with a preponderance for facial involvement, compared with the truncal preponderance in ashy dermatosis. Ashy dermatosis tended to have a more stable clinical course than lichen planus pigmentosus, which was more likely to wax and wane. The utility of histopathology in differentiating between the two conditions is low. CONCLUSION: Ashy dermatosis and lichen planus pigmentosus, as defined in this study, appear to be two separate clinical entities with distinguishable clinical features and natural histories.

Noninvasive real-time characterization of non-melanoma skin cancers with handheld optoacoustic probes.

Currently, imaging technologies that enable dermsurgeons to visualize non-melanoma skin cancers (NMSC) in vivo preoperatively are lacking, resulting in excessive or incomplete removal. Multispectral optoacoustic tomography (MSOT) is a volumetric imaging tool to differentiate tissue chromophores and exogenous contrast agents, based on differences in their spectral signatures and used for high-resolution imaging of functional and molecular contrast at centimeter scale depth. We performed MSOT imaging with two- and three-dimensional handheld scanners on 21 Asian patients with NMSC. The tumors and their oxygenation parameters could be distinguished from normal skin endogenously. The lesion dimensions and depths were extracted from the spectral melanin component with three-dimensional spatial resolution up to 80 µm. The intraclass correlation coefficient correlating tumor dimension measurements between MSOT and ex vivo histology of excised tumors, showed good correlation. Real-time 3D imaging was found to provide information on lesion morphology and its underlying neovasculature, indicators of the tumor's aggressiveness.

Repigmentation in vitiligo: position paper of the Vitiligo Global Issues Consensus Conference.

The Vitiligo Global Issues Consensus Conference (VGICC), through an international e-Delphi consensus, concluded that 'repigmentation' and 'maintenance of gained repigmentation' are essential core outcome measures in future vitiligo trials. This VGICC position paper addresses these core topics in two sections and includes an atlas depicting vitiligo repigmentation patterns and color match. The first section delineates mechanisms and characteristics of vitiligo repigmentation, and the second section summarizes the outcomes of international meeting discussions and two e-surveys on vitiligo repigmentation, which had been carried out over 3 yr. Treatment is defined as successful if repigmentation exceeds 80% and at least 80% of the gained repigmentation is maintained for over 6 months. No agreement was found on the best outcome measure for assessing target or global repigmentation, therefore highlighting the limitations of e-surveys in addressing clinical measurements. Until there is a clear consensus, existing tools should be selected according to the specific needs of each study. A workshop will be conducted to address the remaining issues so as to achieve a consensus.

Twelve-month and sixty-month outcomes of noncultured cellular grafting for vitiligo.

BACKGROUND: Noncultured cellular grafting is a known surgical technique for vitiligo. OBJECTIVE: This study evaluated our center's 12-month repigmentation outcome and its maintenance up to 60 months, factors influencing repigmentation and safety data. METHODS: Clinicoepidemiologic and repigmentation data were reviewed for patients with vitiligo who had undergone noncultured cellular grafting from March 2006 to December 2012 at the National Skin Center, Singapore. RESULTS: All 177 patients who received noncultured cellular grafting during the study period were included. For those with available data, good to excellent repigmentation was present in 83% at 60 months. At 12 months, 88% of patients (n = 52) with segmental vitiligo achieved good to excellent repigmentation compared with 71% (n = 55) with nonsegmental vitiligo (P < .05). More patients on collagen dressings (82%) achieved good to excellent repigmentation compared with those who received hyaluronic acid (63%) (P < .05). Sites of lesions and postgrafting phototherapy did not significantly affect repigmentation outcome. Adverse reactions were uncommon and mild. LIMITATIONS: The study is limited by its retrospective nature, the progressive loss to follow-up of patients, the absence of blinding, and the lack of use of standardized assessment tools. CONCLUSION: Noncultured cellular grafting was successful in allowing more than 80% of patients to achieve good to excellent repigmentation for at least 60 months.

Periorbital hyperpigmentation in Asians: an epidemiologic study and a proposed classification.

BACKGROUND: Periorbital hyperpigmentation (POH) presents with a dark area surrounding the eyelids. It is an ill-defined condition, and the pathogenesis can be multifactorial. OBJECTIVE: This epidemiologic study was conducted to assess the prevalence of periorbital hyperpigmentation in Singapore in an attempt to propose a classification. MATERIALS AND METHODS: One thousand consecutive patients attending the general dermatology clinic at the National Skin Center were enrolled in the study to assess for POH, of whom 200 with POH were examined and investigated to define the cause of POH. The possible causes were determined according to a detailed history, clinical examination, and assessment by three dermatologists. The extent of the POH was measured using a mexameter. RESULTS: The commonest form of POH was the vascular type (41.8%), followed by constitutional (38.6%), postinflammatory hyperpigmentation (12%), and shadow effects (11.4%). The vascular type was seen predominantly in Chinese, whereas as the constitutional type was most common in Indians and Malays. CONCLUSION: The vascular form of POH was the predominant type. We propose a comprehensive classification for POH that we hope will influence the choice of treatment modalities used in managing POH in the future.

Progressive macular hypomelanosis in Singapore: a clinico-pathological study.

INTRODUCTION: Progressive macular hypomelanosis (PMH), a condition of uncertain etiology, is characterized by asymptomatic hypopigmented macules predominantly located on the trunk. To date, there are no reports from South-East Asia concerning this condition. We sought to record the clinical features of PMH in Asian patients, identify etiologic factors, and study the structural and ultrastructural features of melanocytes in this disorder. METHODS: Patients who presented to the National Skin Center with acquired, hypopigmented macules on the trunk, without a history of inflammation or infection, were recruited. Erythrocyte sedimentation rate (ESR), complete blood count, fasting blood glucose, liver function tests, skin scrapings for fungi, and skin biopsy specimens (from lesional and normal skin) were obtained. Biopsies were stained with hematoxylin and eosin (H&E), Fontana Masson, an immunohistochemical panel for identification of melanocyte differentiation antibodies (HMB 45, Melan A, and S100) and CD 68. Electron microscopy (EM) was also performed. The patients were evaluated every 3 months. RESULTS: During a 9 month period, eight patients (all Chinese) presented with hypopigmented, ill-defined, confluent macules involving the lower aspect of the trunk. There were four men and four women, and the mean age was 25.9 years (range 19-45 years). Skin scrapings were negative for fungi and laboratory tests were normal. Microscopic evaluation of skin biopsy specimens showed reduced pigmentation of lesional as compared with normal appearing skin, but H&E-stained sections revealed only minimal histologic differences between lesional and normal skin. EM demonstrated a statistically significant (P = 0.047, Wilcoxon Signed Rank Test, Wilcoxon 95% CI 0.02-0.62) higher ratio of stage IV and late stage III (dark) melanosomes in normal vs. lesional skin. CONCLUSIONS: PMH may occur among young adults in Singapore. Its etiology is uncertain. The melanin content of lesional skin appears to be less than that in normal sites. EM shows a higher ratio of immature melanosomes in lesional vs. normal skin.

Three cases of transition from pemphigus vulgaris to pemphigus foliaceus confirmed by desmoglein ELISA.

We report 3 cases of pemphigus vulgaris (PV) confirmed by histology and direct and indirect immunofluorescence that showed transition to pemphigus foliaceus (PF) 2-4 years from the time of disease onset. Desmoglein (Dsg) ELISA testing of the sera from these 3 patients in the later stages of their disease showed the presence of anti-Dsg1 antibodies and the absence of anti-Dsg3 antibodies. These patients were on prednisolone and immunosuppressives at the time the sera were tested, and it is unclear if the transition from PV to PF is a permanent one or whether it is due to preferential suppression of Dsg3 antibodies below a certain threshold. Previously reported cases of transition from PV to PF and PF to PV are summarized.