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Background The number needed to treat ratio is an effective method for measuring accuracy in melanoma detection. Dermoscopy reduces the number of false positives and subsequently unnecessary excisions. In vivo confocal microscopy is a non-invasive technique which allows the examination of the skin with cellular resolution. Objectives To assess the impact of RCM analysis on the number of equivocal lesions, assumed to be melanocytic, excised for every melanoma. Methods Consecutive patients (n=343) presenting with doubtful lesions, were considered for enrolment. The lesions were analysed by dermoscopy and RCM and histopathological assessment was considered the reference standard. The main outcome was the number needed to treat, calculated as the proportion of equivocal lesions, excised for every melanoma. Results Dermoscopy alone obtained a hypothetical NNT of 3.73, the combination of dermoscopy and RCM identified 264 equivocal lesions that qualified for excision, 92 of which were confirmed to be a melanoma; resulting in a NNT of 2.87; whereas the analysis of RCM images classified as melanoma 103 lesions with a consequent NNT of 1.12; the difference in the reduction of this ratio was statistically significant (p< 0.0001) between the three groups. There was no significant improvement in sensitivity when comparing the combination of dermoscopy and RCM and RCM alone (94.56% vs. 97.82%; p = 0.043). However, the differences between specificities were statistically significant (p <0.000001), favouring RCM alone. Conclusion The addition of RCM analysis to dermoscopy reduces unnecessary excisions with a high diagnostic accuracy and could be a means for reducing the economic impact associated with the management of skin cancer.

Background: Cutaneous melanoma spreads preferentially through the lymphatic route and sentinel lymph node (SLN) status is regarded as the most important predictor of survival. Aims: To evaluate whether tumour lymphangiogenesis and the expression of vascular endothelial growth factor C (VEGF-C) is related to the risk of SLN metastasis and to clinical outcome in a case-control series of patients with melanoma. Methods: Forty five invasive melanoma specimens (15 cases and 30 matched controls) were investigated by immunostaining for the lymphatic endothelial marker D2-40 and for VEGF-C. Lymphangiogenesis was measured using computer assisted morphometric analysis. Results: Peritumorous lymphatic vessels were more numerous, had larger average size, and greater relative area than intratumorous lymphatics. The number and area of peritumorous and intratumorous lymphatics was significantly higher in melanomas associated with SLN metastasis than in non-metastatic melanomas. No significant difference in VEGF-C expression by neoplastic cells was shown between metastatic and non-metastatic melanomas. Using logistic regression analysis, intratumorous lymphatic vessel (LV) area was the most significant predictor of SLN metastasis (p = 0.04). Using multivariate analysis, peritumorous LV density was an independent variable affecting overall survival, whereas the intratumorous LV area approached significance (p = 0.07). Conclusions: This study provides evidence that the presence of high peritumorous and intratumorous lymphatic microvessel density is associated with SLN metastasis and shorter survival. The intratumorous lymphatic vessel area is the most significant factor predicting SLN metastasis. The tumour associated lymphatic network constitutes a potential criterion in the selection of high risk patients for complementary treatment and a new target for antimelanoma therapeutic strategies.

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