Pre-operative diagnosis of pigmented skin lesions: in vivo dermoscopy performs better than dermoscopy on photographic images

BACKGROUND: Epiluminescence microscopy (ELM) (dermoscopy, dermatoscopy) is a technique for non-invasive diagnosis of pigmented skin lesions that improves the diagnostic performance of dermatologists. Little is known about the possible influence of associated clinical features on the reliability of dermoscopic diagnosis during in vivo examination. OBJECTIVE: To compare diagnostic performance of in vivo dermoscopy (combined clinical and dermoscopic examination) with that of dermoscopy performed on photographic slides (pure dermoscopy). DESIGN: This case series comprised 256 pigmented skin lesions consecutively identified as suspicious or equivocal during examination in a general dermatological clinic. Clinical examination and in vivo dermoscopy were performed before excision by two trained dermatologists. The same observers carried out dermoscopy on photographic slides at a later time, and these three diagnostic classifications were reviewed together with the histological findings for the individual lesions. This was carried out in a university hospital. RESULTS: In vivo dermoscopy performed better than dermoscopy on photographic slides for classification of pigmented skin lesions compared with histological diagnosis, and both performed better than general clinical diagnosis. In vivo dermoscopic diagnosis of melanoma showed 98.1% sensitivity, 95.5% specificity and 96.1% diagnostic accuracy while dermoscopic diagnosis of melanoma on photographic slides was less reliable with 81.5% sensitivity, 86.7% specificity and 85.2% diagnostic accuracy. In particular, diagnosis of melanoma based on photographic slides led to nine false negative cases (three in situ, six invasive; thickness ranges 0.2-1.5 mm). CONCLUSIONS: In vivo dermoscopy, i.e. combined clinical and dermoscopic examination, is more reliable than dermoscopy on photographic slides. In clinical practice, therefore, in vivo dermoscopy cannot be considered independent from associated clinical characteristics of the lesions, which help the trained observer to reach a more precise classification. This may have implications on the reliability of ELM diagnosis made by an observer not fully trained in the clinical diagnosis of pigmented skin lesions or by a remote observer during digital ELM teleconsultation.     

Diagnosis of pigmented skin lesions by dermoscopy: web-based training improves diagnostic performance of non-experts

BACKGROUND: Dermoscopy has been shown to enhance the diagnosis of melanoma. However, use of dermoscopy requires training and expertise to be effective. OBJECTIVES: To determine whether an Internet-based course is a suitable tool in teaching dermoscopy, and to evaluate the diagnostic value of pattern analysis and diagnostic algorithms in colleagues not yet familiar with this technique. METHODS: Sixteen colleagues who were not experts in dermoscopy were asked to evaluate the dermoscopic images of 20 pigmented skin lesions using different diagnostic methods (i.e. pattern analysis, ABCD rule, seven-point checklist and Menzies' method), before and after an Internet-based training course on dermoscopy. Mean +/- SEM sensitivity, specificity and diagnostic accuracy, and kappa (kappa) intraobserver agreement were evaluated for each diagnostic method before and after training for the 16 participants. Differences between mean values were assessed by means of two-tailed Wilcoxon rank-sum tests. RESULTS: There was a considerable improvement in the dermoscopic melanoma diagnosis after the Web-based training vs. before. Improvements in sensitivity and diagnostic accuracy were significant for the ABCD rule and Menzies' method. Improvements in sensitivity were also significant for pattern analysis, whereas the sensitivity values were high for the seven-point checklist in evaluations both before and after training. No significant difference was found for specificity before and after training for any method. There was a significant improvement in the kappa intraobserver agreement after training for pattern analysis and the ABCD rule. For the seven-point checklist and Menzies' method there was already good agreement before training, with no significant improvement after training. CONCLUSIONS: We demonstrated that Web-based training is an effective tool for teaching dermoscopy.     

Digital dermoscopy analysis of atypical pigmented skin lesions: a stepwise logistic discriminant analysis approach

Background: Digital microscopy is a non-invasive diagnostic technique enabling determination of characteristics that cannot be appreciated by direct observation. If correctly applied, this technique can be useful for the diagnosis of pigmented skin lesions.
Purpose: To evaluate the utility of digital microscopy for analysing atypical benign and malignant pigmented skin lesions exploiting digital numerical filtering and automatic measurements.
Methods: Forty-eight parameters were identified as possible discriminating variables, and were grouped in four categories: geometries, colours, textures, and islands of colour. Statistical analysis was used to identify the variables with the highest discriminating power.
Results: The high quality of the digital image made it possible to observe diagnostic signs in pigmented skin lesion images, acquired by the present technique, in great detail. Specially designed filtering enhanced certain diagnostic patterns. Stepwise discriminant analysis selected only 10 variables (the means of these variables were higher in melanomas than in nevi).
Conclusions: The combined use of digital dermoscopy and stepwise logistic discriminant analysis made it possible to single out the best objective variables for distinguishing atypical nevi and early melanoma.     

Dermoscopy of pigmented skin lesions

Dermoscopy is an in vivo method for the early diagnosis of malignant melanoma and the differential diagnosis of pigmented lesions of the skin. It has been shown to increase diagnostic accuracy over clinical visual inspection in the hands of experienced physicians. This article is a review of the principles of dermoscopy as well as recent technological developments.     

Dermoscopy of pigmented skin lesions

This paper describes the basic concepts of dermoscopy, the various dermoscopic equipments and the standard criteria for diagnosing pigmented skin lesions. In assessing dermoscopic images, both global and local features can be recognized. These features will be systematically described and illustrated in Part I of this article. First, we will focus on 8 morphologically rather distinctive global features that allow a quick, preliminary categorization of a given pigmented skin lesion. Second, we will describe various local features representing the letters of the dermoscopic alphabet. The local features permit a more detailed assessment of pigmented skin lesions.     

Correlation between dermoscopy and histopathology in pigmented and non-pigmented skin tumours

Dermoscopy (dermatoscopy, epiluminescence microscopy, surface microscopy) is a non-invasive method in dermatology. With this method pigmented and non-pigmented skin tumours can be diagnosed with a clear higher sensitivity and specificity compared to clinical examination. Malignant skin tumours are detected earlier and unnecessary excisions of benign skin tumours can be avoided. The knowledge about the correlation between dermoscopy and histopathology is hereby an essential condition. In this continuing medical education article the correlation of both examination techniques is presented for the dermoscopic differential diagnoses.     

Diagnostic and neural analysis of skin cancer (DANAOS). A multicentre study for collection and computer-aided analysis of data from pigmented skin lesions using digital dermoscopy

BACKGROUND: Early detection of melanomas by means of diverse screening campaigns is an important step towards a reduction in mortality. Computer-aided analysis of digital images obtained by dermoscopy has been reported to be an accurate, practical and time-saving tool for the evaluation of pigmented skin lesions (PSLs). A prototype for the computer-aided diagnosis of PSLs using artificial neural networks (NNs) has recently been developed: diagnostic and neural analysis of skin cancer (DANAOS). OBJECTIVES: To demonstrate the accuracy of PSL diagnosis by the DANAOS expert system, a multicentre study on a diverse multinational population was conducted. METHODS: A calibrated camera system was developed and used to collect images of PSLs in a multicentre study in 13 dermatology centres in nine European countries. The dataset was used to train an NN expert system for the computer-aided diagnosis of melanoma. We analysed different aspects of the data collection and its influence on the performance of the expert system. The NN expert system was trained with a dataset of 2218 dermoscopic images of PSLs. RESULTS: The resulting expert system showed a performance similar to that of dermatologists as published in the literature. The performance depended on the size and quality of the database and its selection. CONCLUSIONS: The need for a large database, the usefulness of multicentre data collection, as well as the benefit of a representative collection of cases from clinical practice, were demonstrated in this trial. Images that were difficult to classify using the NN expert system were not identical to those found difficult to classify by clinicians. We suggest therefore that the combination of clinician and computer may potentially increase the accuracy of PSL diagnosis. This may result in improved detection of melanoma and a reduction in unnecessary excisions.     

皮肤镜在某些色素性皮肤病诊断中的应用价值

目的：探讨皮肤镜在色素性和非色素性皮肤病的临床诊断中的应用价值。方法：对某些色素性和非色素性皮肤病的临床诊断、皮肤镜诊断和皮肤病理活检结果进行比较。结果：皮肤镜对于咖啡斑及甲下出血等临床常见色素性疾病的良恶性判断率特异度和灵敏度达到100%;对于恶性黑素瘤、色素痣、脂溢性角化的特异度和灵敏度也较高。结论：皮肤镜对于黑素瘤、色素性痣、细胞痣及脂溢性角化的良恶性判断具有较好的辅助诊断和临床应用价值。     

In vivo epiluminescence microscopy of pigmented skin lesions. I. Pattern analysis of pigmented skin lesions

The importance of recognizing early melanoma is generally accepted. Because not all pigmented skin lesions can be diagnosed correctly by their clinical appearance, additional criteria are required for the clinical diagnosis of such lesions. In vivo epiluminescence microscopy provides for a more detailed inspection of the surface of pigmented skin lesions, and, by using the oil immersion technic, which renders the epidermis translucent, opens a new dimension of skin morphology by including the dermoepidermal junction into the macroscopic evaluation of a lesion. In an epiluminescence microscopy study of more than 3000 pigmented skin lesions we have defined morphologic criteria that are not readily apparent to the naked eye but that are detected easily by epiluminescence microscopy and represent relatively reliable markers of benign and malignant pigmented skin lesions. These features include specific patterns, colors, and intensities of pigmentation, as well as the configuration, regularity, and other characteristics of both the margin and the surface of pigmented skin lesions. Pattern analysis of these features permits a distinction between different types of pigmented skin lesions and, in particular, between benign and malignant growth patterns. Epiluminescence microscopy is thus a valuable addition to the diagnostic armamentarium of pigmented skin lesions at a clinical level.     

Dispelling myths concerning pigmented skin lesions

The history of medicine is replete with examples of debunked myths, and in daily clinical dermatological practice, we must still counter many misconceptions regarding pigmented lesions, both with patients and other medical practitioners. Debunking myths and attempting to explain the reasons for these erroneous beliefs are the purposes of this review. The literature review has been partially guided by the results obtained from an online questionnaire conducted on an Italian website ( www.vediamocichiara.it ) from February 15, 2015 to March 15, 2015. The remaining discussed were selected on the basis of the existing literature and our personal experience. In order to explore these misconceptions, the following are the seven most salient questions that require investigation: (i) Is it dangerous to excise moles?; (ii) Is it dangerous to traumatize moles?; (iii) Are plantar moles worrisome?; (iv) Is it necessary to selectively apply sunscreen to moles?; (v) Is it inadvisable to partially biopsy a melanoma?; (vi) Do moles turn into melanoma?; and (vii) Is it necessary to perform sentinel lymph node biopsy for thin melanomas and for atypical Spitz naevi? Myths are ubiquitous, being prevalent in dermatological practice, with many of them concerning pigmented skin lesions. By encouraging critical analysis by patients and medical practitioners, the birth and perpetuation of myths can potentially be minimized, for the ultimate benefit of patients. This requires a scientific approach to be rigorously applied to dermatology, with critical questioning of unsubstantiated hypotheses including those emanating from the mass media as well as from respected sources.     

A simple scoring system for the diagnosis of palmo‐plantar pigmented skin lesions by digital dermoscopy analysis

Background Many research groups have recently developed equipments and statistical methods enabling pattern classification of pigmented skin lesions. To differentiate between benign and malignant ones, the mathematical extraction of digital patterns together with the use of appropriate statistical approaches is a challenging task. Objective To design a simple scoring model that provides accurate classification of benign and malignant palmo‐plantar pigmented skin lesions, by evaluation of parameters obtained by digital dermoscopy analysis (DDA). Patients and Methods In the present study we used a digital dermoscopy analyser to evaluate a series of 445 palmo‐plantar melanocytic skin lesion images (25 melanomas 420 nevi). Area under the receiver operator curve, sensitivity and specificity were calculated to evaluate the diagnostic performance of our scoring model for the differentiation of benign and malignant palmo‐plantar melanocytic lesions. Results Model performance reached a very high value (0.983). The DDA parameters selected by the model that proved statistically significant were: area, peripheral dark regions, total imbalance of colours, entropy, dark area and red and blue multicomponent. When all seven model variables were used in a multivariate mode, setting sensitivity at 100% to avoid false negatives, we estimated a minimum specificity of about 80%. Conclusions Simplicity of use and effectiveness of implementation are important requirements for the success of quantitative methods in routine clinical practice. Scoring systems meet these requirements. Their outcomes are accessible in real time without the use of any data processing system, thus allowing decisions to be made quickly and effectively.