Several distinct melanoma syndromes have been defined, and genetic tests are available for the associated causative genes.,Guidelines for melanoma genetic testing have been published as an informal “rule of twos and threes,” but these guidelines apply to CDKN2A testing and are not intended for the more recently described non-CDKN2A melanoma syndromes.,In order to develop an approach for the full spectrum of hereditary melanoma patients, we have separated melanoma syndromes into two types: “melanoma dominant” and “melanoma subordinate.”,Syndromes in which melanoma is a predominant cancer type are considered melanoma dominant, although other cancers, such as mesothelioma or pancreatic cancers, may also be observed.,These syndromes are associated with defects in CDKN2A, CDK4, BAP1, MITF, and POT1.,Melanoma-subordinate syndromes have an increased but lower risk of melanoma than that of other cancer(s) seen in the syndrome, such as breast and ovarian cancer or Cowden syndrome.,Many of these melanoma-subordinate syndromes are associated with well-established predisposition genes (e.g., BRCA1/2, PTEN).,It is likely that these predisposition genes are responsible for the increased susceptibility to melanoma as well but with lower penetrance than that observed for the dominant cancer(s) in those syndromes.,In this review, we describe our extension of the “rule of twos and threes” for melanoma genetic testing.,This algorithm incorporates an understanding of the spectrum of cancers and genes seen in association with melanoma to create a more comprehensive and tailored approach to genetic testing.
The incidence of melanoma among the Asian population is lower compared to that among the Western European population.,These populations differed in their most common histopathologic subtypes, acral lentiginous melanoma being the most common in the Asian population.,Although the dermoscopic features of the melanomas on the acral skin have been thoroughly investigated in the Asian population, studies concerning the dermoscopic patterns of melanomas on the non-acral skin have been scarce.,The aim of this study was to investigate the dermoscopic patterns of melanomas on the trunk and extremities in the Asian population.,To achieve this, we evaluated the dermoscopic patterns of 22 primary melanomas diagnosed at two university hospitals in Korea.,In addition, 100 benign melanocytic lesions were included as the control group for comparative analysis.,A P value less than 0.05 was regarded as statistically significant.,Melanoma-associated dermoscopic features such as asymmetry (odds ratio [OR], 30.00), multicolor pattern (OR, 30.12), blotches (OR, 13.50), blue white veils (OR, 15.75), atypical pigment networks (OR, 9.71), irregular peripheral streaks (OR, 6.30), atypical vascular patterns (OR, 11.50), ulcers (OR, 15.83), atypical dots/globules (OR, 3.15), shiny white lines (OR, 5.88), and regression structures (OR, 7.06) were more commonly observed in patients with melanomas than in patients of the control group.,The mean dermoscopic scores obtained on the 7-point checklist, revised 7-point checklist, 3-point checklist, ABCD rule, and CASH algorithm were 5.36, 3.41, 2.05, 6.89, and 9.68, respectively, in the primary melanomas, and 1.33, 0.93, 0.46, 2.45, and 3.60, respectively, in the control group (all, P < 0.001).,The present study showed that melanoma-related dermoscopic patterns were common in Asian patients.,Dermoscopy is a reliable diagnostic tool for the melanomas of the trunk and extremities in the Asian populations.