Correlation of dermoscopic structures of basal cell carcinoma
Leaflike areas and spoke wheel areas
Leaflike areas are brown to blue-gray projections connected radially to a common base, which remind the shape of leaves (Kittler et al., 2016a). Spoke wheel areas are a variant of leaflike areas where radial projections emerge from a dark brown central hub. Sometimes the projections are ill-defined and may resemble concentric structures (clod within a clod). In the absence of pigment network they are highly suggestive of pigmented BCC. (Aimilios Lallas et al., 2015) Histologically, they represent dermal aggregates of pigmented BCC nests at the DEJ and in the papillary dermis (table 6) (Aimilios Lallas et al., 2015).
Blue-gray ovoid nests, multiple blue-gray globules and dots
Ovoid nests are well-circumscribed blue-gray oval clods, larger than globules. Histologically, they reveal large BCC nodules in the dermis. Blue-gray globules and dots (in-focus dots) are multiple non-aggregated oval structures smaller than nests. Histologically, they correspond to small pigmented BCC nests in the dermis (Aimilios Lallas et al., 2015).
Ulcerations and erosions
Ulcerations are larger red to orange structureless areas. Histologically, they correspond with loss of the entire epidermis (reaching the papillary dermis). A single ulceration is highly suggestive of nodular BCC, but can also be observed in melanoma, SCC or traumatized lesions (table 7) (Aimilios Lallas et al., 2015). Erosions are small brown-red to orange-yellow crusts. Histopathologically, they correspond to partial epidermal loss (Aimilios Lallas et al., 2015). Multiple small erosions are associated with superficial BCC, but can also occur in traumatized lesions (Ahnlide et al., 2016).
Shiny white blotches and strands
Shiny white blotches are small to large white homogenous areas. Strands are parallel and linear white areas that usually do not intersect (Liebman et al., 2012). The exact histopathological correlate is unknown, but they seem to correspond to dermal fibrosis. The combined presence of shiny white blotches and strands is associated with a high diagnostic specificity for nonpigmented BCC (Navarrete-Dechent et al., 2016).
Arborizing vessels and serpentine vessels
Arborizing vessels are bright red large-diameter vessels, with distinct treelike branching into finer capillaries, sharply focused on dermoscopy. They are highly suggestive of BCC, especially nodular BCC, but can also be seen in other tumoral and non-tumoral dermatosis such as hypertrophic scars/keloids, epidermal cysts, actinic keratoses intradermal nevi, among others (Jin et al., 2017). Histologically, they may correlate with a major need for vascularization in nodular BCC compared with superficial BCC (Micantonio et al., 2011). Unfocused arborizing vessels can also be observed in BCC, but in a lower proportion (Jin et al., 2017). Other vessels found in BCC, especially superficial BCCs, include serpentine vessels which are short thin vessels that do not branch significantly (Micantonio et al., 2011).
