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Home Topics A–Z Concentric circles dermoscopy
Author: Naomi Ashman, Dermoscopist, Torbay Skin, Auckland, New Zealand; DermNet New Zealand Editor in Chief Adjunct A/Prof Amanda Oakley, Dermatologist, Hamilton, New Zealand. Created January 2019.
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Concentric circles are a specific clue to melanoma on the face (lentigo maligna), but the clue has poor sensitivity as they are rarely present. In a study by Tschandl et al, concentric circles were only found in 4.2% of flat facial melanomas, usually larger lesions [1]. Concentric circles are also referred to as a circle within a circle and the isobar sign.
Concentric circles consist of an asymmetrical pigmented follicular opening with a darker dot located within ostial openings.
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