Clinical and dermoscopic variation of basal cell carcinoma according to age of onset and anatomic location: a multicenter, retrospective study.

Basal cell carcinoma (BCC) is rare in young individuals and reported to possess different pathogenetic, clinical and histological features from late-onset BCC. However, the dermoscopic variability of BCC according to age of onset has not been investigated. Anatomic location was revealed to be associated with dermoscopic variation of BCC in Western population, but whether it applies to Asian population remains unknown. We evaluated the clinical and dermoscopic features of 448 BCCs and compared each feature by age of onset (age < 50/ > 50 years) and anatomic location. Early-onset BCCs occurred more frequently on non-sun-exposed sites (OR 3.28, P = 0.001) and were less pigmented than late-onset BCCs (P = 0.003). Blue-gray globules (OR 1.74, P = 0.037) and no vessels (OR 2.04, P = 0.021) were independently associated with early-onset BCCs, whereas arborizing telangiectasia (OR 0.30, P < 0.001), large blue-gray ovoid nests (OR 0.38, P < 0.001) and ulceration (OR 0.33, P < 0.001) were less common in early-onset BCCs. Scalp BCCs were significantly more pigmented than BCCs located elsewhere (P = 0.022). Superficial subtype (OR 5.90, P < 0.001), spoke-wheel areas (OR 4.78, P = 0.034), superficial erosions (OR 4.69, P = 0.003) and polymorph vessels (OR 6.86, P = 0.001) were independently associated with trunk BCCs, whereas nodular subtype (OR 5.48, P < 0.001) and arborizing telangiectasias (OR 3.64, P < 0.001) with BCCs on face and neck. Our findings suggest that age of onset and anatomic location are independent factors affecting the dermoscopic appearance of BCC.