Shiny white structures
Shiny white structures (SWS) (formerly known as crystalline structures or chrysalis) are only seen with polarized dermoscopy and may require the operator to rotate the dermatoscope over the lesion to see them (angular dependence). SWS include shiny white streaks, shiny white blotches and strands, and rosettes. SWS are white lines oriented orthogonally, parallel or perpendicularly to each other (Kittler et al., 2016a). Histologically, they correlate to stromal alteration and fibrosis (increased dermal collagen), and are secondary to the birefringent properties of collagen bundles (Pizzichetta et al., 2014). Shiny white streaks can be observed in melanomas, atypical genital nevi, Spitz nevi, and LPLKs (Pizzichetta et al., 2014; Shitara et al., 2014). They also correlate with dermal invasion in cases of melanoma (Balagula et al., 2012).
Shiny while lines / streaks
Christalline structures are white shiny linear streaks that are seen under polarized dermoscopy, but not under nonpolarized dermoscopy. The white streaks are oriented parallel, and sometimes also orthogonal (perpendicular) to each other. Chrysalis structures can be seen in scars, dermatofibromas, basal cell carcinomas, and also in melanomas and Spitz nevi. These structures correlate histopathologically with altered collagen in the dermis (fibrosis). The birefringent properties of collagen bundles cause rapid randomization of polarized light. This is the reason collagen appears bright white and more conspicuous under polarized dermoscopy .
An example of shiny white lines as they appear in polarized (right image) as opposed to non-polarized dermoscopy (left image):
Shiny white blotches and strands
This structure can only be seen with polarized dermoscopy and consists of white patches or blotches and linear white areas called strands .
Rosettes (also known as ‘four-clod dots’) are deﬁned as four white points, arranged as a four leaf clover. They are not lesion-speciﬁc and are described in many tumoral and inflammatory lesions, including: scars, dermatofibroma, actinic keratosis, squamous cell carcinoma and melanoma and more. Smaller rosettes are mainly caused by polarizing horny material at infundibular level in adnexal openings and larger rosettes mainly by concentric perifollicular ﬁbrosis .
- Verzi et al.: The diagnostic value and histologic correlate of distinct patterns of shiny white streaks for the diagnosis of melanoma: A retrospective, case-control study. J. Am. Acad. Dermatol. 2018;78:913-919. PMID: 29138058. DOI.
- Navarrete-Dechent et al.: Association of Shiny White Blotches and Strands With Nonpigmented Basal Cell Carcinoma: Evaluation of an Additional Dermoscopic Diagnostic Criterion. JAMA Dermatol 2016;152:546-52. PMID: 26792406. DOI.
- Haspeslagh et al.: Rosettes and other white shiny structures in polarized dermoscopy: histological correlate and optical explanation. J Eur Acad Dermatol Venereol 2016;30:311-3. PMID: 25786770. DOI.