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The presence of distinct patterns of shiny white streaks (SWS) on polarized dermoscopy is an important sign of malignancy in melanocytic neoplasms and should prompt biopsy, according to results of a recent retrospective, case-control study published in the Journal of the American Academy of Dermatology.
The investigators sought to evaluate the frequency and specificity of SWS in melanoma in 1507 consecutive melanocytic lesions chosen for biopsy and for which a dermoscopic image was available. The specificity of different patterns of SWS for melanoma and the specificity of SWS for melanoma when combined with other melanoma-specific features was also assessed.
The histology of all lesions with SWS and all detected melanomas were assessed in order to better characterize the histologic changes associated with SWS.
Of 1507 melanocytic neoplasms, SWS were detected in 22% (31 of 144) of melanomas and 1.6% (22 of 1363) of benign neoplasms (P <.001). The overall sensitivity of SWS for melanoma was 22% (31 of 144) and the specificity was 98% (1341 of 1363). The positive predictive value (PPV) was 58% and the negative predictive value (NPV) was 92%.
A diffuse distribution of SWS was detected in 12% of melanomas and 0.51% of benign melanocytic neoplasms (P<.001). Diffuse SWS had the greatest diagnostic value for melanoma, with a sensitivity of 11.8% and a specificity of 99.5%.
Focal central SWS and peripheral SWS were both comparable in diagnostic significance, with PPV and NPV values of 70.8% and 91.4%, respectively. Focal SWS were observed in 9.7% (14 of 144) of melanomas and in 1.1% (15 of 1363) of benign melanocytic neoplasms (P <.001). The types of melanomas included 4 melanomas in situ, 9 T1 melanomas, and 1 T2 melanoma.
The investigators concluded that the presence of diffuse SWS in this population was the most predictive for the presence of melanoma. Lesions with this finding should be biopsied to rule out the presence of melanoma.
Reference
Verzi AE, Quan VL, Walton K, 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 [published online November 11, 2017]. J Am Acad Dermatol. doi:10.1016/j.jaad.2017.11.021
