Purpose of Review Reflectance confocal microscopy (RCM) enables imaging of skin lesions at cellular level resolution at the bedside (in vivo) or in freshly excised tissue (ex vivo). This article provides an overview of strengths and limitations of non-invasive RCM in skin cancer diagnosis. Recent Findings RCM features of common melanocytic and non-melanocytic skin neoplasms such as melanoma, actinic keratosis/squamous cell carcinoma, basal cell carcinoma, and nevi have been well defined and show good correlation with dermoscopic and histopathologic findings. Due to its technical properties, RCM is especially suitable for the examination of flat skin lesions. Summary In vivo RCM has been shown to increase the accuracy of non-invasive diagnosis of common skin neoplasms and is a valuable adjunct to dermoscopy, particularly in cosmetically and functionally sensitive areas such as the face or the genital area.

ImmunoCAP ISAC E112i (ISAC) and Allergy Explorer 2 (ALEX²) detect specific immunoglobulin E (IgE) reactivity. Both multiplex assays contain molecular allergens and ALEX² additionally includes allergen extracts and inhibitors that block the binding of IgE to cross-reacting carbohydrate determinants (CCDs). This study aimed to compare the performance of ISAC and ALEX² by determining the IgE reactivity against allergen extracts and/or allergen components and by using qualitative, semiquantitative, and quantitative analyses of all comparable allergen components in sera from 216 participants recruited in South Tyrol/Italy. For extract sensitization in ALEX², the analysis revealed negative corresponding allergen components in 18.4% and at least one positive corresponding allergen component in 81.6% of all cases. For ISAC, the corresponding results were 23.5% and 76.5% of cases, respectively. The ALEX² CCD inhibitor eliminated CCD-positive signals detected by ISAC in 88.5% of cases. Based on sensitization values of 0.3–14.9 ISU or kU_A/L, there was good agreement between ALEX² and ISAC, although ALEX² showed higher values than ISAC. The addition of allergen-extract tests in ALEX² resulted in the detection of more sensitizations than with corresponding allergen components alone. In the range of <15 ISU or kU_A/L, ALEX² may be more effective in detecting sensitizations.

Background: Nevus spilus (NS) is a potential precursor of melanoma; the vast majority of cases reported in the literature were histologically classified as superficial spreading melanoma. Objective: To demonstrate the diagnostic value of reflectance confocal microscopy (RCM) in this subtype of congenital nevi. Methods: We report a case of a large congenital NS with equivocal clinical and dermoscopic findings in which RCM was applied for diagnosis and follow-up. Results: There was a good correlation of RCM with histopathology and a lack of dynamic changes during follow-up. Conclusion: Our observations indicate that RCM, as a non-invasive tool, can be useful for diagnosis and follow-up of clinically and dermoscopically equivocal NS.

Summary: Background and objective: Benign and malignant facial skin lesions may be difficult to differentiate clinically and with dermoscopy. The present study aimed to evaluate the potential utility of in vivo reflectance confocal microscopy (RCM) as a second‐level examination for facial skin neoplasms.Patients and Methods: Retrospective and blinded evaluation of 160 consecutive facial lesions was carried out in two separate steps. Clinical and dermoscopic images were assessed first, followed by combined evaluation of clinical/dermoscopic and RCM images. Our study included 60 % malignant lesions, comprising 43 % melanomas, 9 % basal cell carcinomas, 5 % in situ squamous cell carcinomas and 3 % lymphomas.Results: Ancillary RCM significantly improved diagnostic specificity for the detection of malignancy compared to clinical/dermoscopic evaluation alone (58 % vs 28 %). However, sensitivity was slightly lower for RCM‐based image evaluation (93 % vs 95 %) due to misclassification of one in situ SCC and one lymphoma. In terms of melanoma diagnosis, RCM‐based image evaluation was generally superior; sensitivity was only slightly increased (88 % vs 87 %), but melanoma specificity was significantly higher (84 % vs 58 %).Conclusion: RCM is a valuable diagnostic adjunct for facial skin lesions; unnecessary biopsies in this cosmetically sensitive area could be reduced by one third without missing a melanoma.

Hintergrund und Zielsetzung Benigne und maligne Läsionen der Gesichtshaut können klinisch und dermatoskopisch schwierig zu differenzieren sein. Die vorliegende Studie zielte darauf ab, den diagnostischen Nutzen der In‐vivo‐Konfokalmikroskopie (RCM) als weiterführende Untersuchungsmethode für Neubildungen der Gesichtshaut zu untersuchen. Patienten und Methodik Retrospektive und verblindete Untersuchung von 160 konsekutiven Gesichtsläsionen in zwei getrennten Schritten: zuerst Auswertung der klinischen und dermatoskopischen Bilder, gefolgt von einer kombinierten Beurteilung der klinischen, dermatoskopischen und RCM‐Bilder. Unsere Studie schloss 60 % maligne Läsionen ein, bestehend aus 43 % Melanomen, 9 % Basalzellkarzinomen, 5 % In‐situ‐Plattenepithelkarzinomen und 3 % Lymphomen. Ergebnisse Die zusätzliche RCM verbesserte die diagnostische Spezifität für die Erkennung von Malignomen im Vergleich zur klinisch‐dermatoskopischen Auswertung allein deutlich (58 % vs. 28 %). Die Sensitivität war für die RCM‐basierte Auswertung jedoch wegen der Fehlbeurteilung eines In‐situ‐Plattenepithelkarzinoms und eines Lymphoms etwas erniedrigt (93 % vs. 95 %). Im Bezug auf die Melanomdiagnose schnitt die RCM‐basierte Bildauswertung generell besser ab; die Sensitivität war nur gering erhöht (88 % vs. 87 %), die Spezifität jedoch deutlich (84 % vs. 58 %). Schlussfolgerungen Die RCM stellt ein wertvolles diagnostisches Hilfsmittel im Gesichtsbereich dar; die Anzahl unnötiger Biopsien in diesem kosmetisch sensiblen Areal könnte, ohne ein Melanom zu übersehen, um ein Drittel reduziert werden.