Differenzierung von kombinierten Nävi und Melanomen: Fallkontrollstudie mit komparativer Analyse der dermatoskopischen Merkmale.

HINTERGRUND: Kombinierte Nävi (KN) zeigen zwei oder mehr Komponenten bestimmter Nävustypen und stellen klassische Melanomsimulatoren dar. In dieser Studie wurde eine vorab definierte Auswahl dermatoskopischer Merkmale sowie drei diagnostische Algorithmen hinsichtlich der Differenzierung von KN und Melanomen evaluiert. PATIENTEN UND METHODIK: Retrospektive, verblindete Fallkontrollstudie mit Vergleich dermatoskopischer Bilder von 36 KN sowie 36 Melanomen. Insgesamt wurden 21 dermatoskopische Merkmale, die Anzahl der Farben sowie drei diagnostische Algorithmen (ABCD-Regel, Menzies-Score, 7-Punkte-Checkliste) untersucht. ERGEBNISSE: 5 von 7 typischen Nävus-Merkmalen wurden signifikant häufiger in KN im Vergleich zu Melanomen gefunden (alle p < 0,05) und zwei Merkmale wurden ausschließlich in KN gefunden. 11 von 14 typischen Melanom-Merkmalen wurden signifikant häufiger in Melanomen im Vergleich zu KN gefunden (alle p < 0,03) und fünf Merkmale wurden ausschließlich in Melanomen gefunden. Die mittlere (± SD) Anzahl der Farben in KN war niedriger im Vergleich zu den Melanomen (2,1 ± 0,6 vs. 3,4 ± 0,7; p < 0,001). Bei den untersuchten Algorithmen zeigte die ABCD-Regel der Dermatoskopie die beste diagnostische Leistung (Sensitivität 91,7 %, Spezifität 77,8 %). SCHLUSSFOLGERUNGEN: Die ABCD-Regel der Dermatoskopie erzielte die beste Differenzierung von KN und Melanomen. Zusätzliches Wissen über KN- oder Melanom-spezifische dermatoskopische Merkmale kann zur sicheren klinischen Diagnose beitragen.

Differentiation of combined nevi and melanomas: Case-control study with comparative analysis of dermoscopic features.

BACKGROUND AND OBJECTIVES: Combined nevi (CN) show two or more components of major nevus subtypes and simulate melanomas. We investigated a panel of dermoscopic features and three dermoscopic algorithms for differentiating CN from melanomas. PATIENTS AND METHODS: Retrospective, blinded case-control study using dermoscopic images of 36 CN and 36 melanoma controls. Twenty-one dermoscopic features validated for the diagnosis of melanocytic lesions, the number of colors, and three dermoscopic algorithms were investigated (ABCD rule of dermoscopy, Menzies scoring method, 7-point checklist). RESULTS: Five of seven features indicative of nevi were observed significantly more frequently in CN than in melanomas (all p < 0.05) and two were exclusively found in CN. Eleven out of 14 features indicative of melanomas were observed significantly more frequently in melanomas than in CN (all p < 0.03) and five were exclusively found in melanomas. The mean (± SD) number of colors in CN was lower than in melanomas (2.1 ± 0.6 versus 3.4 ± 0.7; p < 0.001). Among tested algorithms the ABCD rule of dermoscopy performed best (sensitivity 91.7 %, specificity 77.8 %). CONCLUSIONS: The ABCD rule of dermoscopy differentiated CN from melanomas most efficiently. Additional knowledge of dermoscopic features to be expected exclusively in either CN or melanomas should help dermatologists to make a correct clinical diagnosis.

Impact of UV-irradiation on electrical impedance spectroscopy of benign nevi: study protocol for a prospective, controlled, clinical study.

INTRODUCTION: The clinical and histological changes of nevi after ultraviolet (UV) irradiation have been studied in detail. In contrast, the impact of UV irradiation on electrical impedance spectroscopy scores of nevi has not been investigated. However, for physicians, it is essential to know the extent to which changes in electrical impedance spectroscopy scores of nevi may be attributed to seasonal effects of UV irradiation. METHODS: This is a prospective, controlled, clinical study evaluating the impact of UV irradiation on the electrical impedance spectroscopy scores of benign nevi in 50 patients undergoing phototherapy. To this end, benign nevi of patients with a medical indication for phototherapy will be measured by electrical impedance spectroscopy before, during and after UV irradiation. At the same time, non-irradiated nevi of the same patient will be measured to account for changes over time that are independent of direct UV irradiation. ETHICS AND DISSEMINATION: Ethical approval was obtained from the ethics committee of the medical faculty of the University of Heidelberg (ethics approval number S-279/2017). The design and the final results of the study will be published and made available to the public. TRIAL REGISTRATION NUMBER: DRKS00012456; Pre-results.