Amelanotic/hypomelanotic melanoma: clinical and dermoscopic features.

Background Amelanotic malignant melanoma is a subtype of cutaneous melanoma with little or no pigment on visual inspection. It may mimic benign and malignant variants of both melanocytic and nonmelanocytic lesions. Objectives To evaluate whether dermoscopy is also a useful technique for the diagnosis of amelanotic ⁄ hypomelanotic melanoma (AHM). Methods We conducted a retrospective clinical study of 151 amelanotic⁄hypomelanotic skin lesions from 151 patients with a mean age of 47 years (± 17Æ5 SD). Digitized images of amela- notic ⁄ hypomelanotic skin lesions were converted to JPEG format and sent by e-mail from the five participating centres. Lesions included 55 amelanotic⁄hypomelanotic nonmelanocytic lesions (AHNML), 52 amelanotic⁄hypomelanotic benign melanocytic lesions (AHBML), and 44 AHM, 10 (23%) of which were nonpigmented, truly amelanotic melanomas (AM). The 44 AHM lesions were divided into thin melanomas (TnM) £ 1 mm (29 cases) and thick melanomas (TkM) > 1 mm (15 cases), acco