Diagnostic value of dermoscopic findings in the differentiation of atypical nevus from melanoma

Objective: Atypical nevi clinically and histologically demonstrates some features of benign melanocytic nevi and melanoma. Melanoma is one of the most common types of cancer in young adults, and the incidence and mortality rates have increased in recent years. The definitive diagnostic method in skin malignancies is histopathological examination. Dermoscopy is widely used in the screening of pigmented lesions as a method of examination between clinical observation and histopathological examination. The diagnostic accuracy is high when it is done with experienced people. In this study, it was aimed to determine the value of dermoscopic findings at the discrimination of atypical nevus and melanoma. Materials and Methods: In our study, dermoscopic views of lesions that have been histopathologically proven by excision after dermoscopic examinations with preliminary diagnosis of atypical nevus and melanoma in the outpatient clinic of skin and venereal diseases at Cukurova University Faculty of Medicine were analyzed retrospectively. 24 melanomas, 146 atypical nevi were included in the study. Dermoscopic images were examined in terms of benign nevus patterns, melanoma-specific structures, asymmetry, border irregularity, color, and dermoscopic structures. Results: A total of 170 patients (85 female, 85 male) were included in the study. The mean age was found as 31.23 years in the all patient group, 48.59 years in the melanomas and 28.38 years in the atypical nevi. Atypical nevi were found most frequently in the front and back of the trunk, and the melanoma was most commonly located in the head and neck. Benign nevus patterns include patchy reticulary, peripheral reticulary and central hyperpigmentation, peripheral globular, central reticular or homogeneous area; melanoma-specific structures include radial streaming, pseudopods, irregular streaks, blue-white structures in raised areas, blue-white structures in flat areas "regression structures"; and presence of asymmetry, increase in color number and number of dermoscopic structures from general dermoscopic features were found to be statistically significant in the discrimination of the two lesions. Conclusion: Atypical nevi can become a melanoma imitator and potential precursor. A small number of studies have been carried out with regard to the common criteria for distinguishing melanoma and atypical nevus. We think that the data we have found can help dermatologists distinguish atypical nevi from melanoma. In particular, lesions with radial streaming, pseudopods, irregular streaks and regression structures should be carefully examined. Keywords: Atypical nevus, Dermoscopy, Dysplastic nevus, Melanoma