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Concentric circles dermoscopy
What are concentric circles?
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.
What do concentric circles look like through the dermatoscope?
Concentric circles consist of an asymmetrical pigmented follicular opening with a darker dot located within ostial openings.
In which lesions are concentric circles seen in through the dermatoscope?
- Lentigo maligna
- Pigmented actinic keratosis (rarely).
Concentric circles seen in dermoscopy of a lentigo maligna. Courtesy of Prof Cliff Rosendahl Concentric circles seen in dermoscopy of a lentigo maligna on the ear Concentric circles seen in dermoscopy of lentigo maligna on the face Concentric circles seen in dermoscopy of lentigo maligna on the ear Concentric circles seen in dermoscopy of pigmented actinic keratosis Concentric circles seen in dermoscopy of a pigmented actinic keratosis on the scalp
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Related information
References
- Dermatoscopy, Pattern analysis of pigmented and non-pigmented lesions by Harold Kittler, Cliff Rosendahl, Alan Cameron, Philip Tschandl; 2nd edition, 2016; Facultas Verlags- und Buchandels AG facultas Universitatsverlag, Vienna, Austria. Chapter 8, Special situations, P274.
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