Exploring the Severity Strata of Disease Activity and Repigmentation in Vitiligo Based on Validated Physician Global Assessment (PGA) Scores.

Background/Objectives: There is currently no guidance on how to interpret the global degrees of activity (worsening) and repigmentation (improvement) in vitiligo. Stratification into global degrees can be completed for static evaluations (e.g., visible disease activity signs) and dynamic assessments (e.g., evolution over time). For the latter, the Vitiligo Disease Activity Score (VDAS15&60) and Vitiligo Disease Improvement Score (VDIS15&60) were recently validated. Methods: In the current study, a Physician Global Assessment (PGA) for disease activity (worsening) and repigmentation (improvement) was evaluated for validity (construct) and reliability (inter- and intrarater) based on a photo set of 66 patients. Subsequently, the PGA activity (worsening) and repigmentation (improvement) were used to stratify the Vitiligo Extent Score plus (VESplus), VDAS15&60 or VDIS15&60 into three global categories (slightly, moderately and much worse/improved), based on ROC analysis. Results: For the VESplus, cut-off values for the categories 'slightly, moderately and much worse' were >0.3%, >27.71% and >128.75% BSA (relative changes in the affected total BSA), respectively. For the categories 'slightly, moderately and much improved', they were >0%, >4.87% and >36.88% BSA (relative changes in the affected total BSA), respectively. The optimal cut-off values of the number of active (VDAS15) body areas were >0 areas for slightly worse, >2 areas for moderately worse and >7 for much worse. For VDIS15, the cut-off values for slightly improved and moderately improved were >0 and >1. For VDAS60 and VDIS60, the cut-off points were >0.5, >3, >9.5 and >0.5 and >1.5, respectively. The results should be interpreted with caution in patients with extensive vitiligo due to the rather limited disease extent of the included patient population (VESplus (median: 3.2%)). Conclusions: This research will aid in the development of more detailed international definitions.

Preoperative assessment of cutaneous melanoma thickness by multispectral dermoscopy.

Preoperative assessment of Breslow thickness by means of sonography and clinical and dermoscopic criteria in white light dermoscopy has been reported, but up until now, the use of multispectral dermoscopy has not been investigated. Aim of this research is to determine whether multispectral dermoscopy and more specifically pigment maps can be used as a predictive marker for Breslow thickness in melanoma. Pigment maps are generated in real time from multispectral dermoscopic images and help to visualize the presence of pigment in a lesion. Multispectral images of 110 melanomas were collected, using a digital handheld multispectral dermatoscope, and assessed independently by five observers for the presence or absence of deep pigment compared with the surrounding skin. According to histopathological examination, the mean Breslow thickness of all 110 melanomas was 1.04 mm (ranging from 0.1 to 14 mm). The group of melanomas where deep pigment was visualized on the multispectral image (n = 78) had a significantly higher Breslow thickness (1.19 mm) than the group where no deep pigment was observed (n = 32, mean Breslow 0.68 mm) (P = 0.025). This study is unique in preoperative assessment of tumour thickness by means of multispectral dermoscopy. Our data indicate that the presence of deep pigment as visualized in digital dermoscopic skin parameter maps identifies a group of thicker melanomas. Further prospective research is needed to validate these pigment maps, generated by multispectral dermoscopy as a measure to predict invasiveness in melanoma.

Can Multispectral Dermoscopy Help In Distinguishing Blue Color?

INTRODUCTION: The interpretation of colors is essential in the dermoscopic evaluation of skin lesions. The same blue color on white dermoscopy may indicate blood or pigment deep in the dermis. Contrary to white dermoscopy, multispectral dermoscopy uses different wavelengths of light to illuminate a lesion and is able to decompose the dermoscopic image into individual maps that allow to more clearly visualize specific skin structures such as pigment distribution (pigment map) and vasculature (blood map). These maps are called skin parameter maps. OBJECTIVES: The aim of this research is to investigate whether skin parameter maps can be used to objectively identify and distinguish the presence of pigment and blood, by using blue naevi and angiomas as models for respectively pigment and blood. METHODS: We retrospectively analyzed 24 blue naevi and 79 angiomas. The skin parameter maps of each of the lesions were independently reviewed by 3 expert dermoscopists, in the absence of the regular white-light dermoscopic image. RESULTS: All the observers provided high levels of diagnostic accuracy for blue naevus and angioma based on skin parameter maps alone, and the dermoscopic diagnosis was considered substantially reliable because of the 79% of diagnostic K agreement. Percentages of blue naevi and angiomas that showed respectively deep pigment and blood were very high at 95.8% and 97.5%. There was a percentage of lesions that counterintuitively showed blood in blue naevi (37.5%) and deep pigment in angiomas (28.8%). CONCLUSIONS: Skin parameter maps based on multispectral images can help to objectify the presence of deep pigment or blood in blue naevi and angiomas. The application of these skin parameter maps could help in the differential diagnosis between pigmented and vascular lesions.