Dermoscopic island: a new descriptor for thin melanoma

Area of Science:

• Dermatology
• Dermoscopy
• Oncology

Background:

• Dermoscopy enhances melanoma diagnosis, but specific early indicators remain limited.
• The dermoscopic island (DI) is a newly defined feature in pigmented lesions.
• A DI is a distinct, uniform area within a larger lesion with a different pattern.

Purpose of the Study:

• To determine the frequency and characteristics of the dermoscopic island (DI).
• To assess the diagnostic specificity of the DI for melanoma.
• To evaluate the DI's association with melanoma subtypes and clinical features.

Main Methods:

• Dermoscopic images of 96 in situ melanomas, 266 invasive melanomas, and 612 atypical nevi were analyzed.
• The presence and pattern of the DI were recorded.
• Clinical and histological data were correlated with DI presence.

Main Results:

• The DI was observed in 10.4% of in situ melanomas, 4.1% of invasive melanomas, and 3.1% of atypical nevi.
• The odds ratio for melanoma was 1.922, with a specificity of 96.9%.
• Melanomas with a DI were thinner and often arose on a nevus; the DI pattern was typically reticular.

Conclusions:

• The dermoscopic island (DI) is characteristic of thin melanoma, especially when arising on a nevus.
• The DI may serve as an early sign of nevus to melanoma transformation.
• This descriptor aids in identifying early-stage melanomas.