Dermoscopy Essentials: Shiny White Lines

Dermoscopy Essentials: Shiny White Lines

So-called "shiny white lines" (aka, 'chrysalis,' 'orthogonal streaks' or 'crystalline' structures) are shining white lines or streaks that a key sign to look out for when performing dermoscopy. Their association with melanoma underscores the importance of all dermoscopists familiarizing themselves with the sign and its significance. 

Discovery 

A study was performed in 2012 which compared the appearance of dermoscopic features/structures under polarized and non-polarized lighting.1 In some lesions, shiny white lines having parallel and orthogonal orientations were seen, but surprisingly only when using polarized lighting. 

Properties

Various descriptions of these structures have been made, including "bright white lines oriented in both parallel and orthogonal directions." Histopathologically, it's believed that their appearance is due the interaction of polarized light with the birefringent properties of collagen.

Although these lines were visible in both dermatofibromas and basal cell carcinomas. it's their presence in melanoma that causes the greatest concern. In fact, these shiny white lines were noted in more than half of melanomas examined, as well as within a few Spitz nevi. Conversely, shiny white lines are very rare in benign nevi.

Clinical Significance 

The presence of shiny white lines is now widely accepted as a significant finding which should alert the clinician to the possibility of melanoma. As previously described, they can be present in benign, nonmelanocytic lesions (esp. dermatofibroma and lichen planus-like keratosis) as well as nonmelanoma skin cancers (esp. basal cell carcinoma). However, in melanocytic lesions, the presence of shiny white lines is highly concerning clue for melanoma.
In fact, various studies have shown a multifold increased likelihood of a melanoma diagnosis when shiny white lines are visible within melanocytic lesions.

Another benefit of shiny white lines is that they can also serve as a clue to amelanotic melanoma. For example, seeing a pink or light-colored structureless lesion alone may lead the clinician to choose monitoring over biopsy. However, if shiny white/orthogonal lines were noted within that same pink, structureless lesion, the need to biopsy would no longer be in question.

Not only does their presence in pigmented lesions serve as a clue that a lesion is melanoma, but shiny white lines also increase the likelihood that the melanoma is invasive.

"Blink" Sign

For those who find themselves questioning whether they're truly seeing shiny white lines, the "blink" sign can be a useful technique.

The "blink sign" refers to the appearance of shiny white structures "blinking" when the dermoscopist alternates between polarized and non-polarized light mode. Since shiny white structures are only visible under cross-polarized lighting, they will tend to "flash" or "blink" when the dermoscopist switches between non-polarized and polarized light modes.

REFERENCES:

Liebman TN, Rabinovitz HS, Dusza SW, Marghoob AA. White shiny structures: dermoscopic features revealed under polarized light. J Eur Acad Dermatol Venereol. 2012;26(12):1493-1497. doi:10.1111/j.1468-3083.2011.04317.x

Back to blog