Assessment of malignant melanoma lesions using violet‐light dermoscopy: A case report

Abstract

Malignant melanomas often present with irregular shapes and in multiple shades of brown under white light. 1 In pale-toned melanoma, it is often difficult to distinguish the boundary between the lesion and adjacent healthy skin with the naked eye, even with conventional dermoscopy (CDS). The DZ-D100 dermoscope (Casio Computer) is equipped with a violet light-emitting diode (LED), which is a near-ultraviolet (UV) light with a wavelength of 405 nm, in addition to a conventional white LED (Figure 1). Since the absorption wavelength of melanin contains violet light, the combination of CDS and violet-light dermoscopy (VLD) may reveal the distribution of subtle pigmentation of fine melanin in the skin, making it easier to distinguish between lesions and healthy skin.

Clinical study on the comparison of dermoscopic images using two wavelengths of near‐ultraviolet‐visible light

“…Importantly, these grayscale images are meant to complement regular dermoscopic images in the sense that they highlight pale melanin deposition and other features that are not visible on regular dermoscopic images. 5,6 In addition, this is a new technology that is different from the conventionally existing UV-induced fluorescence dermoscopy (UVFD) with similar UV LEDs. 9 In general, UVFD exhibits high refractive index allowing shallow penetration, and evokes UV-induced fluorescence.…”

“…Based on our previous observations, we believe that haemoglobin tones would be enhanced even in P405 images if blocked-up shadows did not cause interference. 6 Regarding photon safety, the visible light range wavelengths used in P405 are considered to have a lower risk of cytotoxicity than those in the UVA range of P385. Unlike UVB, which directly induces DNA damage by forming dimeric photoproducts between adjacent pyrimidine bases on the same strand, UVA and visible light are known to induce oxidative DNA base damage by forming 8-hydroxydeoxyguanosine.…”

“…Consequently, purple light in the near‐UV‐visible region (380–430 nm) also corresponds to the absorption wavelength of melanin, at a relatively high level. Therefore, we jointly developed the DZ‐D100 dermoscopy camera (Casio Computer Co., Ltd.) based on a hypothesis that a dermoscope using both 405 nm purple light‐emitting diode (LED) light and conventional white LED light would be more sensitive for imaging melanin‐containing skin lesions 5,6 . Furthermore, a clinical study was conducted to compare images from a prototype DZ‐D100 equipped with a 385 nm LED (P385), which produces UVA (near UV) light and a 405 nm LED (P405), which emits visible light, to determine which wavelength could more clearly represent dermoscopic structures.…”

Comparison of images obtained using four dermoscope imaging devices: An observational study

“…Therefore, it is desirable to have a dermoscopy device that can easily focus on any lesion and clearly show the findings, and a clear image may be useful for automated dermoscopy diagnoses using machine learning. 2 We conducted a clinical study to compare dermoscopic images of the same skin tumours obtained using a prototype dermoscopy camera, DZ-D100 (DD) (Casio Computer Co., Ltd.), 3,4…”

“…Therefore, it is desirable to have a dermoscopy device that can easily focus on any lesion and clearly show the findings, and a clear image may be useful for automated dermoscopy diagnoses using machine learning 2 . We conducted a clinical study to compare dermoscopic images of the same skin tumours obtained using a prototype dermoscopy camera, DZ‐D100 (DD) (Casio Computer Co., Ltd.), 3,4 and three existing dermoscopy imaging devices (Derma9500S®‐GR [DG], Derma Medical Inc.; DELTA 20® T [DT], HEINE Optotechnik; and DermLite Foto II Pro® [DF], DermLite LLC). The former two are dedicated dermoscopy cameras, and the latter two are imaging devices connected to digital single‐lens reflex (DSLR) cameras (EOS80D; Canon).…”