Clinical and dermoscopic characteristics of melanomas on nonfacial chronically sun-damaged skin.

BACKGROUND: Melanomas on chronically sun-damaged skin (CSDS) can be difficult to identify and often manifest morphologic features that overlap with benign lesions. OBJECTIVE: We describe and analyze the clinical and dermoscopic characteristics of melanomas on nonfacial CSDS. METHODS: Melanoma cases on nonfacial CSDS were retrospectively identified from the biopsy specimen logs of 6 melanoma clinics. Clinical and dermoscopic images were combined into 1 database. Demographics, clinical, dermoscopic, and histopathologic information were analyzed. Descriptive frequencies were calculated. RESULTS: One hundred eighty-six cases met the inclusion criteria: 142 melanomas in situ (76%) and 39 invasive (21%; mean thickness, 0.49 mm). Lentigo maligna was the most common histopathologic subtype (n = 76; 40.9%). The most frequent dermoscopic structures were granularity (n = 126; 67.7%) and angulated lines (n = 82; 44%). Vascular structures were more frequent in invasive melanomas (56% vs 12% of in situ melanomas). Most manifested 1 of 3 dermoscopic patterns: patchy peripheral pigmented islands, angulated lines, and tan structureless with granularity pattern. LIMITATIONS: This was a retrospective study, and evaluators were not blinded to the diagnosis. In addition, interobserver concordance and sensitivity and specificity for dermoscopic structures were not evaluated. CONCLUSION: Outlier lesions manifesting dermoscopic structures, such as granularity, angulated lines, or vessels and any of the 3 described dermoscopic patterns should raise suspicion for melanoma.

The impact of subspecialization and dermatoscopy use on accuracy of melanoma diagnosis among primary care doctors in Australia.

BACKGROUND: Dermatoscopy improves accuracy of melanoma diagnosis, but the impact of subspecialization in skin cancer practice among general practitioners on melanoma diagnostic accuracy is not known. OBJECTIVE: To assess the impact of dermatoscopy use and subspecialization on the accuracy of melanoma diagnosis by general practitioners. METHODS: We did a prospective study on the Skin Cancer Audit Research Database and measured melanoma 'number needed to treat' (NNT), with 21,900 lesions excised to diagnose 2367 melanomas. RESULTS: Melanoma NNT fell from a high of 17.0 (95% confidence interval [CI] 14.5-20.7) among general practitioners with a generalist practice to 9.4 (CI 8.9-10.1) among those with a specific interest in skin cancer, and 8.5 (CI 8.1-9.0) among those practicing only skin cancer medicine (P < .0001). Melanoma NNT fell from a high of 14.6 (CI 12.0-18.6) among dermatoscopy low/non-users to 10.9 (CI 9.8-12.4) among medium users, and 8.9 (CI 8.6-9.3) among high users (P < .0001). The association between NNT and practice type remained (P < .0001) when adjusted for dermatoscopy use and other variables. The association between NNT and dermatoscopy use disappeared (P = .41) when adjusted for practice type and other variables. LIMITATIONS: There is selection bias with respect to participating doctors and completeness and accuracy of data are not independently verified in the Skin Cancer Audit Research Database (SCARD). CONCLUSIONS: General practitioners who subspecialize in skin cancer have a higher use of dermatoscopy and diagnose melanoma with greater accuracy than their generalist counterparts.