The impact of anatomical location and sun exposure on the dermoscopic recognition of atypical nevi and early melanomas: usefulness of an integrated clinical-dermoscopic method (iDScore)

摘要

Background The anatomical location of atypical melanocytic skin lesion (aMSL) was never combined into an algorithm for discriminating early melanomas (EM) from atypical nevi (AN). Aims To investigate the impact of body location on the intuitive diagnosis performed in teledermoscopy by dermatologists of different skill levels. A further aim was to evaluate how the integration of the body location could improve an algorithm-aided diagnosis. Methods We retrospectively collected 980 standardized dermoscopic images of aMSL cases (663 AN, 317 EM): data on the anatomical location were collected according to 15 body sites classified into 4 macro-areas ofchronically/frequently/seldom/rarelyexposure. Through a teledermatology web platform, 111 variously skilled dermoscopists performed either the intuitive diagnosis and 3 algorithm-assisted diagnostic tests (i.e.iDScore, 7-point checklist, ABCD rule) on each case, for a total of 3330 examinations. Results In therarely photoexposedarea (side, bottom, abdomen), AN were the most tricky (i.e. highest quote of false positives), due to a frequent recognition of dermoscopic features usually considered as suggestive for melanoma in these lesions; the EM at these sites received the highest quote of false negatives, being generally interpreted as 'featureless' according to these traditional parameters, that were more frequently displayed on thechronically photoexposed area. In rarely and seldomphotoexposedarea, intuitive diagnosis fails to achieve adequate accuracy for all aMSLs, as the ABCD rule and the 7-point checklist; by applying theiDScore algorithmthe diagnostic performance was increased by 15% in young and 17% in experts. Conclusions The body location of an aMSL can affect the quality of intuitive dermoscopic diagnosis, especially in sun-protected areas. Accuracy can be improved by using theiDScorealgorithm that assigns a different partial score of each body site.