Man against machine reloaded: performance of a market-approved convolutional neural network in classifying a broad spectrum of skin lesions in comparison with 96 dermatologists working under less artificial conditions.

BACKGROUND: Convolutional neural networks (CNNs) efficiently differentiate skin lesions by image analysis. Studies comparing a market-approved CNN in a broad range of diagnoses to dermatologists working under less artificial conditions are lacking. MATERIALS AND METHODS: One hundred cases of pigmented/non-pigmented skin cancers and benign lesions were used for a two-level reader study in 96 dermatologists (level I: dermoscopy only; level II: clinical close-up images, dermoscopy, and textual information). Additionally, dermoscopic images were classified by a CNN approved for the European market as a medical device (Moleanalyzer Pro, FotoFinder Systems, Bad Birnbach, Germany). Primary endpoints were the sensitivity and specificity of the CNN's dichotomous classification in comparison with the dermatologists' management decisions. Secondary endpoints included the dermatologists' diagnostic decisions, their performance according to their level of experience, and the CNN's area under the curve (AUC) of receiver operating characteristics (ROC). RESULTS: The CNN revealed a sensitivity, specificity, and ROC AUC with corresponding 95% confidence intervals (CI) of 95.0% (95% CI 83.5% to 98.6%), 76.7% (95% CI 64.6% to 85.6%), and 0.918 (95% CI 0.866-0.970), respectively. In level I, the dermatologists' management decisions showed a mean sensitivity and specificity of 89.0% (95% CI 87.4% to 90.6%) and 80.7% (95% CI 78.8% to 82.6%). With level II information, the sensitivity significantly improved to 94.1% (95% CI 93.1% to 95.1%; P < 0.001), while the specificity remained unchanged at 80.4% (95% CI 78.4% to 82.4%; P = 0.97). When fixing the CNN's specificity at the mean specificity of the dermatologists' management decision in level II (80.4%), the CNN's sensitivity was almost equal to that of human raters, at 95% (95% CI 83.5% to 98.6%) versus 94.1% (95% CI 93.1% to 95.1%); P = 0.1. In contrast, dermatologists were outperformed by the CNN in their level I management decisions and level I and II diagnostic decisions. More experienced dermatologists frequently surpassed the CNN's performance. CONCLUSIONS: Under less artificial conditions and in a broader spectrum of diagnoses, the CNN and most dermatologists performed on the same level. Dermatologists are trained to integrate information from a range of sources rendering comparative studies that are solely based on one single case image inadequate.

Standardization of dermoscopic terminology and basic dermoscopic parameters to evaluate in general dermatology (non-neoplastic dermatoses): an expert consensus on behalf of the International Dermoscopy Society.

BACKGROUND: Over the last few years, several articles on dermoscopy of non-neoplastic dermatoses have been published, yet there is poor consistency in the terminology among different studies. OBJECTIVES: We aimed to standardize the dermoscopic terminology and identify basic parameters to evaluate in non-neoplastic dermatoses through an expert consensus. METHODS: The modified Delphi method was followed, with two phases: (i) identification of a list of possible items based on a systematic literature review and (ii) selection of parameters by a panel of experts through a three-step iterative procedure (blinded e-mail interaction in rounds 1 and 3 and a face-to-face meeting in round 2). Initial panellists were recruited via e-mail from all over the world based on their expertise on dermoscopy of non-neoplastic dermatoses. RESULTS: Twenty-four international experts took part in all rounds of the consensus and 13 further international participants were also involved in round 2. Five standardized basic parameters were identified: (i) vessels (including morphology and distribution); (ii) scales (including colour and distribution); (iii) follicular findings; (iv) 'other structures' (including colour and morphology); and (v) 'specific clues'. For each of them, possible variables were selected, with a total of 31 different subitems reaching agreement at the end of the consensus (all of the 29 proposed initially plus two more added in the course of the consensus procedure). CONCLUSIONS: This expert consensus provides a set of standardized basic dermoscopic parameters to follow when evaluating inflammatory, infiltrative and infectious dermatoses. This tool, if adopted by clinicians and researchers in this field, is likely to enhance the reproducibility and comparability of existing and future research findings and uniformly expand the universal knowledge on dermoscopy in general dermatology. What's already known about this topic? Over the last few years, several papers have been published attempting to describe the dermoscopic features of non-neoplastic dermatoses, yet there is poor consistency in the terminology among different studies. What does this study add? The present expert consensus provides a set of standardized basic dermoscopic parameters to follow when evaluating inflammatory, infiltrative and infectious dermatoses. This consensus should enhance the reproducibility and comparability of existing and future research findings and uniformly expand the universal knowledge on dermoscopy in general dermatology.

Diagnostic performance of a deep learning convolutional neural network in the differentiation of combined naevi and melanomas.

BACKGROUND: Deep learning convolutional neural networks (CNN) may assist physicians in the diagnosis of melanoma. The capacity of a CNN to differentiate melanomas from combined naevi, the latter representing well-known melanoma simulators, has not been investigated. OBJECTIVE: To assess the diagnostic performance of a CNN when used to differentiate melanomas from combined naevi in comparison with dermatologists. METHODS: In this study, a CNN with regulatory approval for the European market (Moleanalyzer-Pro, FotoFinder Systems GmbH, Bad Birnbach, Germany) was used. We attained a dichotomous classification (benign, malignant) in dermoscopic images of 36 combined naevi and 36 melanomas with a mean Breslow thickness of 1.3 mm. Primary outcome measures were the CNN's sensitivity, specificity and the diagnostic odds ratio (DOR) in comparison with 11 dermatologists with different levels of experience. RESULTS: The CNN revealed a sensitivity, specificity and DOR of 97.1% (95% CI [82.7-99.6]), 78.8% (95% CI [62.8-89.1.3]) and 34 (95% CI [4.8-239]), respectively. Dermatologists showed a lower mean sensitivity, specificity and DOR of 90.6% (95% CI [84.1-94.7]; P = 0.092), 71.0% (95% CI [62.6-78.1]; P = 0.256) and 24 (95% CI [11.6-48.4]; P = 0.1114). Under the assumption that dermatologists use the CNN to verify their (initial) melanoma diagnosis, dermatologists achieve an increased specificity of 90.3% (95% CI [79.8-95.6]) at an almost unchanged sensitivity. The largest benefit was observed in 'beginners', who performed worst without CNN verification (DOR = 12) but best with CNN verification (DOR = 98). CONCLUSION: The tested CNN more accurately classified combined naevi and melanomas in comparison with trained dermatologists. Their diagnostic performance could be improved if the CNN was used to confirm/overrule an initial melanoma diagnosis. Application of a CNN may therefore be of benefit to clinicians.

Dermoscopic features of mammary Paget's disease: a retrospective case-control study by the International Dermoscopy Society.

BACKGROUND: Mammary Paget's disease (MPD) is a rare intraepidermal adenocarcinoma of the nipple-areola complex, associated with an underlying breast cancer in approximately 90% of cases. Delayed diagnosis of MPD is common. Its dermoscopic features have been ill defined in the literature. OBJECTIVES: To determine the clinical and dermoscopic features of MPD versus other dermatologic entities that involve nipple and areola. METHODS: Members of the IDS were invited to submit any case of histologically confirmed MPD, as well as other benign and malignant dermatoses that involve the nipple and areola complex. A standardized evaluation of the dermoscopic images was performed and the results were statistically analyzed. RESULTS: Sixty-five lesions were included in the study, 22 (33.8%) of them MPD and 43 (66.2%) controls. The most frequent dermoscopic criteria of MPD were white scales (86.4%) and pink structureless areas (81.8%), followed by dotted vessels (72.7%), erosion/ulceration (68.2%) and white shiny lines (63.6%). The multivariate analysis showed that white scales and pink structureless areas were significant predictors of MPD, posing a 68-fold and a 31-fold probability of MPD, respectively. Split of the population into pigmented and non-pigmented lesions showed that in pigmented MPD, pink structureless areas, white lines and grey granules and dots are positive predictors of the disease. Among non-pigmented lesions, pink structureless areas, white lines, erosion/ulceration and white scales served as predictors of MPD. CONCLUSIONS: The most frequent profile of an individual with MPD is an elderly female with unilateral, asymptomatic, erythematous plaque of the nipple, dermoscopically displaying pink structureless areas, fine white scales, dotted and a few short linear vessels. In case of pigmentation we may also observe brown structureless areas and pigmented granules. LIMITATIONS: Small sample size, retrospective design.

[Dermoscopy in special locations : Nails, acral skin, face, and mucosa]. / Dermatoskopie in Sonderlokalisationen : Nägel, akrale Haut, Gesicht und Mukosa.

The use of dermoscopy by dermatologists across Europe has become a standard examination for benign and malignant skin lesions and increasingly also for inflammatory skin diseases. However, based on the experience of the authors from numerous dermoscopy courses, knowledge about important dermoscopic features in special locations such as mucosa or nails is often limited. This may be explained by (1) a different anatomy of the skin and its adnexa in special locations in comparison to the remaining integument, (2) difficult technical access to special locations with a dermatoscope, and (3) a rather low incidence of malignant skin neoplasms in areas of special locations (with the exception of facial skin/scalp). This article aims at explaining dermoscopic characteristics and features of important benign and malignant lesions of nails, acral skin, face, and mucosa.

Enhanced Absorption by Linewidth Narrowing in Optically Excited Type-II Semiconductor Heterostructures.

We experimentally report a surprising linewidth narrowing of the direct exitonic 1 s heavy-hole transition in a type-II quantum well system. This narrowing, which builds up on a pico- to nanosecond timescale, causes a transient enhanced absorption at the spectral peak position of the excitonic resonance. We discuss how this effect depends on experimental parameters such as excitation density, temperature, and barrier width. We cannot attribute this effect to known physical mechanisms.

Atomic structure of 'W'-type quantum well heterostructures investigated by aberration-corrected STEM.

The atomic structure of (GaIn)As/Ga(AsSb)/(GaIn)As-'W'-type quantum well heterostructures ('W'-QWHs) is investigated by scanning transmission electron microscopy (STEM). These structures were grown by metal organic vapour phase epitaxy and are built for type-II laser systems in the infrared wavelength regime. For two samples grown at 525°C and 550°C, intensity profiles are extracted from the STEM images for each sublattice separately. These intensity profiles are compared to the one obtained from an image simulation of an ideal 'W'-QWH that is modelled in close agreement with the experiment. From the intensity profiles, the width of the different quantum wells (QWs) can be determined. Additionally, characteristics connected to the growth of the structures, such as segregation coefficients and material homogeneity, are calculated. Finally, composition profiles are derived from the STEM intensity profiles to a first approximation. For these composition profiles, the expected photoluminescence (PL) is computed based using the semiconductor luminescence equations. The PL spectra are then compared to experimental measurements for both samples.

Recombination dynamics of type-II excitons in (Ga,In)As/GaAs/Ga(As,Sb) heterostructures.

(Ga,In)As/GaAs/Ga(As,Sb) multi-quantum well heterostructures have been investigated using continuous wave and time-resolved photoluminescence spectroscopy at various temperatures. A complex interplay was observed between the excitonic type-II transitions with electrons in the (Ga,In)As well and holes in the Ga(As,Sb) well and the type-I excitons in the (Ga,In)As and Ga(As,Sb) wells. The type-II luminescence exhibits a strongly non-exponential temporal behavior below a critical temperature of T c = 70 K. The transients were analyzed in the framework of a rate-equation model. It was found that the exciton relaxation and hopping in the localized states of the disordered ternary Ga(As,Sb) are the decisive processes to describe the dynamics of the type-II excitons correctly.

Clinical and dermoscopic clues to differentiate pigmented nail bands: an International Dermoscopy Society study.

BACKGROUND: Longitudinal melanonychia might be difficult to differentiate and the use of dermoscopy can be useful for the preoperative evaluation and management decision. OBJECTIVES: The aim of our study was to investigate clinical and dermoscopic criteria of acquired longitudinal melanonychia in adults to identify the best predictors of melanoma using a multivariate analysis and to explore eventual new dermoscopic criteria for nail melanoma diagnosis. METHODS: In this retrospective observational study, 82 histopathologically diagnosed, acquired nail pigmented bands were collected and examined. All variables were included in the analysis and examined as possible predictors of nail melanoma. Both univariate and multivariable analyses have been performed. RESULTS: Among 82 cases, 25 were diagnosed as nail melanoma and 57 as benign lesions (including 32 melanocytic nevi and 25 benign melanocytic hyperplasia). Melanoma cases were significantly associated with a width of the pigmented band higher than 2/3 of the nail plate, grey and black colours, irregularly pigmented lines, Hutchinson and micro-Hutchinson signs, and nail dystrophy. Granular pigmentation, a newly defined dermoscopic criterion, was found in 40% of melanomas and only in 3.51% of benign lesions. CONCLUSIONS: Dermoscopic examination of longitudinal melanonychia provides useful information that could help clinicians to improve melanoma recognition.

[Dermoscopy for malignant and benign skin tumors : Indication and standardized terminology]. / Dermatoskopie bei malignen und benignen Hauttumoren : Indikation und standardisierte Terminologie.

Dermoscopy has a high diagnostic accuracy in pigmented and nonpigmented malignant and benign skin tumors. These microscopic in vivo examinations with polarized and nonpolarized light are effective in the early detection of malignant skin tumors and reduce the number of unnecessary excisions of benign skin tumors. The selection of the skin lesions is crucial for the diagnostic accuracy of the dermoscopic examination. Not only large pigmented skin lesions, but also small hypo-, de-, or nonpigmented skin lesions, should be examined dermatoscopically as well as skin lesions that have changed in shape and/or color. In clinical routine, research and teaching, the dermoscopic diagnosis should be performed by describing the visible structures, their distribution and colors by means of descriptive and/or metaphoric terminology. Optionally, a diagnostic algorithm can also be used. Especially in benign lesions, the dermatoscopic diagnosis should be uniform for the complete area. Comparison with other nearby skin tumors of the same patient (comparative approach) is helpful in the evaluation of numerous melanocytic skin tumors. If it is unclear whether the lesion is malignant, a biopsy or complete excision should be performed with subsequent histopathological examination.

Dermoscopic clues to differentiate facial lentigo maligna from pigmented actinic keratosis.

BACKGROUND: Dermoscopy is limited in differentiating accurately between pigmented lentigo maligna (LM) and pigmented actinic keratosis (PAK). This might be related to the fact that most studies have focused on pigmented criteria only, without considering additional recognizable features. OBJECTIVES: To investigate the diagnostic accuracy of established dermoscopic criteria for pigmented LM and PAK, but including in the evaluation features previously associated with nonpigmented facial actinic keratosis. METHODS: Retrospectively enrolled cases of histopathologically diagnosed LM, PAK and solar lentigo/early seborrhoeic keratosis (SL/SK) were dermoscopically evaluated for the presence of predefined criteria. Univariate and multivariate regression analyses were performed and receiver operating characteristic curves were used. RESULTS: The study sample consisted of 70 LMs, 56 PAKs and 18 SL/SKs. In a multivariate analysis, the most potent predictors of LM were grey rhomboids (sixfold increased probability of LM), nonevident follicles (fourfold) and intense pigmentation (twofold). In contrast, white circles, scales and red colour were significantly correlated with PAK, posing a 14-fold, eightfold and fourfold probability for PAK, respectively. The absence of evident follicles also represented a frequent LM criterion, characterizing 71% of LMs. CONCLUSIONS: White and evident follicles, scales and red colour represent significant diagnostic clues for PAK. Conversely, intense pigmentation and grey rhomboidal lines appear highly suggestive of LM.

[Skin cancer screening in Germany : The situation in 2014 with suggestions for the future]. / Hautkrebsscreening in Deutschland : Eine Bestandsaufnahme im Jahr 2014 mit Vorschlägen für die Zukunft.

Based on the skin cancer screening model of Germany a critical statement is presented about skin cancer epidemiology, the total body examination and time intervals. The number of skin cancer cases will increase and the number of dermatologists will probably decrease; thus a fundamental and pragmatic strategy is required for further education and planning to comply with the increased dermato-oncological demand of an aging population. Hereby dermoscopy should be a basic diagnostic tool for the early recognition of skin cancer and precursors as well as to avoid unnecessary excisions of benign skin lesions. The excision ratio between malignant and benign skin tumours should be optimized.

Five patients with melanosis of the nipple and areola clinically mimicking melanoma.

BACKGROUND: Pigmented lesions on the nipple and areola concern patients and physicians as melanoma and pigmented mammary Paget's disease must be considered in the differential diagnoses. There have been only six case reports of melanosis of the nipple and areola in the medical literature yet five cases presented to our department in a 26-month period. METHOD: Five women aged between 26 and 34 years presented with pigmentation of the areola and/or nipple. Two patients were pregnant and one also had vitiligo. All lesions were solitary, eccentrically located with a sharp but irregular contour, and homogeneous pigmentation. Dermoscopy was performed and reassuring features included light to dark brown cobblestone pigmentation with ring-like structures and reticulation. Blue-white veil and irregular centred black dots were not seen. Histology confirmed melanosis of the nipple and areola. CONCLUSION: Melanosis of the nipple and areola is probably significantly underreported in the medical literature and, based on our experience, is likely to be the most common cause of pigmentation at this site. Considering this, benign condition on clinical and dermoscopic features should lead to biopsy rather than excision to confirm the diagnosis. Further reports of the dermoscopic features will help to define this condition further.

[Dermoscopy of nails]. / Dermatoskopie der Nägel.

Pigmented and nonpigmented nail abnormalities often represent a challenge for clinicians because many, and sometimes potentially life-threatening differential diagnoses must be taken into consideration. Although many details of nail diseases can already be assessed with the naked eye, dermoscopy opens up a second microscopic level of inspection, which can be very useful for the diagnostic process. In the last 20 years dermoscopy has made rapid progress in the further development of criteria for the early recognition of melanoma. In addition, the use of dermoscopy has been extended to the examination of cutaneous adnexa, such as hairs (trichoscopy) and nails (onychoscopy). Many, sometimes highly specific criteria for the dermoscopic assessment of nail diseases have been described in a series of recently published articles. This review article provides important diagnostic aids for a well-founded dermoscopic assessment of nail diseases.

A randomized two-sided placebo-controlled study on the efficacy and safety of atmospheric non-thermal argon plasma for pruritus.

BACKGROUND: To look into new potential indications for physical plasma and because some reports suggest plasma having antipruritic effects, we investigated the treatment of pruritus that often represents a therapeutic challenge. OBJECTIVES: To assess the efficacy and safety of cold atmospheric argon plasma as add-on-therapy in pruritic diseases. METHODS: We treated 46 patients with various pruritic diseases with cold plasma for 2 min daily in addition to standard treatment. All patients served as their own control, when their pruritic disease was treated with argon gas (placebo). The outcome measure was a long-term and short-term reduction in itching measured by means of a visual analogue score (VAS). RESULTS: The VAS scores at baseline were comparable (plasma 4.57, SD 2.38, argon 4.34, SD 2.35). We did not find any significant differences in VAS reduction between plasma and argon: long-term VAS difference of 1.97 (SD 1.33) for plasma and 1.74 (SD 2.37) for argon [P = 0.224, 95% CI: (-0.15; 0.60)], short-term VAS difference of 1.92 (SD 1.33) for plasma and 1.97 (SD 1.29) for argon [P = 0.544, 95% CI: (-0.21; 0.11)]. In both groups, patients experienced a significant reduction of pruritus at the end of therapy compared to baseline [plasma 1.97 (P < 0.0001), placebo 1.74 [P < 0.0001)]. No relevant side effects occurred, and treatment was well tolerated. CONCLUSIONS: Treatment with cold plasma did not result in higher pruritus reduction than treatment with placebo. A significant reduction of pruritus compared to no effect was found at the end of therapy in both groups. Both treatment options had similar safety profiles.

Successful and safe use of 2 min cold atmospheric argon plasma in chronic wounds: results of a randomized controlled trial.

BACKGROUND: The development of antibiotic resistance by microorganisms is an increasing problem in medicine. In chronic wounds, bacterial colonization is associated with impaired healing. Cold atmospheric plasma is an innovative promising tool to deal with these problems. OBJECTIVES: The 5-min argon plasma treatment has already demonstrated efficacy in reducing bacterial numbers in chronic infected wounds in vivo. In this study we investigated a 2-min plasma treatment with the same device and the next-generation device, to assess safety and reduction in bacterial load, regardless of the kind of bacteria and their resistance level in chronic wounds. METHODS: Twenty-four patients with chronic infected wounds were treated in a prospective randomized controlled phase II study with 2 min of cold atmospheric argon plasma every day: 14 with MicroPlaSter alpha device, 10 with MicroPlaSter beta device (next-generation device) in addition to standard wound care. The patient acted as his/her own control. Bacterial species were detected by standard bacterial swabs and bacterial load by semiquantitative count on nitrocellulose filters. The plasma settings were the same as in the previous phase II study in which wounds were exposed for 5 min to argon plasma. RESULTS: Analysis of 70 treatments in 14 patients with the MicroPlaSter alpha device revealed a significant (40%, P<0.016) reduction in bacterial load in plasma-treated wounds, regardless of the species of bacteria. Analysis of 137 treatments in 10 patients with the MicroPlaSter beta device showed a highly significant reduction (23.5%, P<0.008) in bacterial load. No side-effects occurred and the treatment was well tolerated. CONCLUSIONS: A 2-min treatment with either of two cold atmospheric argon plasma devices is a safe, painless and effective technique to decrease the bacterial load in chronic wounds.

Development of a targeted risk-group model for skin cancer screening based on more than 100,000 total skin examinations.

BACKGROUND: Skin cancer screening aims to detect potentially metastasizing skin cancers at an early and surgically curable stage. This may take the form of mass screening, as currently occurs in Germany, or of targeted screening of those at greatest risk. OBJECTIVE: To develop a model to identify patients at high risk of developing skin cancer who would benefit from regular skin cancer screening. METHODS: This was an open prospective point-prevalence study of consecutive patients presenting to dermatologists for a total skin check. Demographic and skin cancer risk factors were recorded and, for the first time, histology of skin lesions was documented. Results were analysed by univariate and multivariate analyses and, after logistic regression with stepwise forward selection, a risk-group model was developed. RESULTS: The results of 108,281 total skin examinations were available for analysis. 142 definite melanomas, 108 severely dysplastic naevi/cannot-exclude-melanoma, 491 basal cell carcinomas (BCC) and 93 squamous cell carcinomas (SCC) were excised. A risk model was developed for melanoma and SCC based on mathematical e-functions. The model had >92% sensitivity for melanoma and SCC and an overall 67.24% specificity for melanoma, SCC and BCC. This targeted risk model identified one-third of the study population as being at risk for the development of melanoma and SCC. CONCLUSIONS: Using the risk calculator developed from this study, targeted screening of the identified at-risk population reduces the numbers needed to be screened regularly by 50%, yet has better sensitivity for melanoma and similar sensitivity for SCC compared to the current mass screening programme in Germany.