Dermoscopy of cutaneous melanoma metastases: A color-based pattern classification

Dermoscopic studies about cutaneous metastases of malignant melanoma (CMMM) are few. Our objective was to analyze the dermoscopic features of CMMM and propose a new dermoscopic pattern classification based on color pigmentation and some specific dermoscopic features. A retrospective evaluation of 150 dermoscopic images of CMMM taken from 40 patients was performed. One hundred CMMM images were individually evaluated by six dermatologists in order to classify them according to four dermoscopic patterns: (i) blue pattern; (ii) pink pattern; (iii) brown pattern; and (iv) mixed pattern. One hundred and fifty dermoscopic images including 50 CMMM and 100 benign lesions were evaluated by five dermatologists to calculate the accuracy of these patterns in the recognition of CMMM. An intra- and interobserver reproducibility agreement study between all different dermoscopic pattern classifications was performed. Seventy-five percent of our cases of CMMM showed a monochromatic pattern. Light brown pigmented halo, peripheral gray spots and polymorphic atypical vessels were the most significant focal dermoscopic structures. The reproducibility of the color-based dermoscopic pattern classification was superior to previous dermoscopic pattern classification. In summary, a dermoscopic pattern classification based on color pigmentation and some specific dermoscopic features may be useful in recognizing early cutaneous melanoma metastasis. Multicentric studies are recommended in order to lower the impact of interobserver variability.