Melanoma diagnosed on digital dermoscopy monitoring: A side-by-side image comparison is needed to improve early detection

Background: Digital dermoscopy monitoring (DDM) helps to recognize melanomas lacking specific dermoscopic features at baseline, but the number of melanomas eventually developing specific features is still unknown. Objective: To assess how many melanomas are identified because they develop melanoma-specific criteria over time compared with melanomas recognized by side-by-side image comparison. Methods: A case-control study was conducted collecting 206 melanomas: 103 melanomas diagnosed during DDM follow-up and 103 melanomas diagnosed at baseline. The control group was composed of 309 benign lesions consisting of 103 nevi excised for diagnostic reasons, 103 not excised nevi, and 103 not excised seborrheic keratoses. Dermoscopic images of all 515 lesions were randomly presented to 2 blinded experts to give a diagnosis and to score the criteria of the 7-point checklist. Results: Of the 103 melanomas diagnosed at baseline, 78.6% (n = 81) were correctly identified compared with only 40.8% (n = 42) of melanomas diagnosed after DDM (P <.001). Of the 103 melanomas excised after DDM, 59.2% (n = 61), did not develop melanoma-specific criteria and were identified only because of the side-by-side image comparison. Limitations: The type of morphologic changes considered as suspicious on DDM was not assessed. Conclusions: Most melanomas are diagnosed with DDM by side-by-side image comparison.