Blue-White Veil — SCE Dermatology MCQ

Correct answer: A — Blue-white veil represents a combination of orthokeratosis (white) overlying aggregated melanin and/or melanophages in the upper dermis (blue) — it is strongly associated with invasive melanoma

The correct answer is A: blue-white veil represents a combination of orthokeratosis (white) overlying aggregated melanin and/or melanophages in the upper dermis (blue), and it is strongly associated with invasive melanoma. The white component comes from compact orthokeratosis and acanthosis in the epidermis, while the blue hue arises from the Tyndall effect as light is scattered by heavily pigmented melanocytes, melanophages or melanin deposited deeper in the dermis. This structure is typically focal, irregular and confined to raised or palpable areas of the lesion rather than covering it uniformly, which helps distinguish melanoma from benign mimics. Its presence, especially combined with other atypical dermoscopic features (irregular blotches, atypical network), significantly raises suspicion for invasive melanoma and should prompt urgent excision biopsy per UK skin cancer pathways. Why the other options are wrong: E. Calcification: Calcified deposits produce a chalky white appearance seen in lesions such as pilomatricomas, not the blue-grey haze of blue-white veil, and are unrelated to melanocytic pigment scattering. D. Fibrosis: Dermal fibrosis (as in dermatofibroma) produces white scar-like or crystalline structures on dermoscopy, not the combined orthokeratosis-plus-dermal-pigment appearance that defines blue-white veil. C. Keratin: Keratin alone accounts only for the white milia-like cysts or comedo-like openings seen in seborrhoeic keratoses, not the blue component derived from dermal pigment. B. Inflammation: Inflammatory infiltrates cause erythema or vascular changes on dermoscopy, not the specific blue-grey Tyndall effect produced by pigmented cells in the papillary dermis. Key point: Blue-white veil equals epidermal orthokeratosis (white) plus dermal pigment/melanophages (blue via Tyndall effect), and its focal, irregular presence is a red flag for invasive melanoma warranting urgent excision.

Reference: Dermoscopedia, Blue white veil / Histopathological correlation, https://dermoscopedia.org/Blue_white_veil (dermoscopy teaching resource consistent with BAD and PCDS training material); see also PCDS Dermoscopy Tutorial, Primary Care Dermatology Society, https://www.pcds.org.uk