Dermatoscopy

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Dermatoscope, lighting exiting at an angle

The Dermatoscopy (Syn .: reflected light microscopy, Epilumineszenzmikroskopie; Engl. Dermoscopy) is a noninvasive and simple examination method of the dermatology , in particular, for early diagnosis of malignant tumors of the skin ( melanoma is used). Here, the skin is examined with a microscope with the help of oil and z. T. also considered polarized light into deeper layers.

Physical basics

Structure of the human skin with appendages

Light that hits the skin is usually largely reflected by the multilayered upper skin (epidermis) ( Fresnel reflection ). By applying immersion oil with a refractive index of 1.5 - 1.8 and immersing the dermatoscope, thanks to the adapted refractive index, the now liquid-filled gap between the skin and the dermatoscope results in much less reflection than when air with a refractive index n = 1 that differs greatly from that of the skin and glass , 0 is present. With the appropriate microscopic magnification and suitable lighting, one can see at most the upper dermis. A further improvement can result from the use of cross-polarization. Here polarized light is used for illumination and exactly the perpendicular polarized light that is scattered back from the skin is observed. The light reflected on the surface is filtered out in this way, as it does not change its polarization, in contrast to the light scattered in the skin.

use

The main area of ​​application of dermatoscopic diagnostics is the detection of early melanomas and the differentiation between melanocytic and non-melanocytic pigment tumors . Dermoscopy can also be used to assess parasites (e.g. scabies ), foreign bodies and bleeding.

literature

  • A. Blum, S. Bosch. Dermoscopy: A Guide to Education and Practice. ; Springer Berlin Heidelberg, 2020; ISBN 978-3-6625-9906-8
  • A. Blum, JF Kreusch, J. Bauer, C. Garbe Dermatoscopy of skin tumors: reflected light microscopy - dermatoscopy - digital image analysis ; Springer-Verlag, 2013; ISBN 978-3-6425-7446-7
  • H. Kittler, P. Tschandl. Dermoscopy: pattern analysis of pigmented and unpigmented skin lesions ; Facultas 2015; ISBN 978-3-7089-1142-7
  • H. Schulz, M. Hundiker, J. Kreusch. Compendium of Dermoscopy ; Springer-Verlag, 2016; ISBN 978-3-6624-9491-2
  • W. Stolz, H. Hänßle, E. Sattler, J. Welzel. Imaging diagnostics in dermatology: dermatoscopy, confocal laser scanning microscopy, optical coherence tomography, sonography ; Georg Thieme Verlag, 2018; ISBN 978-3-1324-0238-6

Web links

  • Article reflected light microscopy in: P. Altmeyer: Encyclopedia of Dermatology, Venereology, Allergology and Environmental Medicine . Springer 2008.