Comparison of classical dermatoscopy and acrylic globe magnifier dermatoscopy

Dermatoscopic asymmetry of melanocytic skin lesion is pivotal in most algorithms assessing the probability of melanoma. Larger lesions cannot be assessed by dermatoscopy and the Dermaphot in a single field of vision, but this can be performed using the acrylic globe magnifier. We examined the diagnostic accuracy of the acrylic globe magnifier and compared it with classical dermatoscopy. A total of 119 patients successively referred to our naevus clinics had Dermaphot and acrylic globe magnifier pictures taken. Lesions were excised and assessed by histopathology. Observers blinded to histopathology diagnoses, assessed dermatoscopic and acrylic globe magnifier photo-slides according to the dermoscopic risk stratification. The observed agreement over all categories between acrylic globe magnifier dermatoscopy and classical dermatoscopy was 94% and Cohen's kappa coefficient was 90% (95% confidence interval 83-97%). Sensitivity for melanoma, benign melanocytic naevi and basal cell carcinoma was 100%, 98% and 85%, respectively. Specificity was 95%, 94% and 100% for melanoma, naevi and basal cell carcinoma. Acrylic globe dermatoscopy enables a diagnostic accuracy similar to epiluminescence microscopy.