Key points in dermoscopy for diagnosis of melanomas, including difficult to diagnose melanomas, on the trunk and extremities.

Early diagnosis and prompt surgical excision are the most important aims in the secondary prevention of cutaneous melanoma. Dermoscopy has increased the accuracy in the detection of melanoma because of dermoscopic-specific features that can be easily detected by trained dermoscopists. However, the classical melanoma-specific criteria such as multicomponent pattern, atypical pigmented network, irregular dots/globules, irregular streaks, multiple colors, blue-whitish veil or regression structures may not be present in all of these lesions. For some early melanomas change, as evidenced by sequential dermoscopic monitoring, may be the only feature suggesting malignancy. At present, even with dermoscopy, the diagnosis of these early melanomas remains to be a challenge for dermatologist. Patient education, digital dermoscopic follow up and consensus diagnosis have been proposed to overcome this problem.