Patterns in Malignant Lesions

Atypical pigment network
(Figure 9.4C)

Thickened line segments (broad-width cords) with irregular width size, irregular distribution, and/or abrupt cutoff of atypical network at periphery

Blue-white veil
(Figure 9.4D)

Overlying blue-white haze or ground glass film over focal areas of lesion due to large melanin-containing areas in upper dermis (such as confluent nests of heavily pigmented melanocytes or melanophages); not associated with red-blue lacunes

White scar-like areas representing areas of regression

Radial parallel linear extensions with asymmetric arrangement at periphery of lesion; can represent radial growth phase of melanoma

Curved finger-like dark brown to black projections at periphery of lesion, appear irregular in distribution or focally at edge of lesion; never appear around entire circumstance (like starburst pattern in Spitz nevus); may represent radial growth phase of melanoma

Dark, linear structures with variable thickness at periphery of lesion; represent heavily pigmented junctional nests of atypical melanocytes

Sharply circumscribed pigmented structures with either irregular shape or distribution; represents aggregation of pigmented melanocytes, melanophages, or even “clumps” of melanin

Various shades of diffuse hyperpigmentation obscuring underlying pattern (i.e., pigment network) with irregular shape; dissimilar structures that share melanin pigmentation through epidermis and upper dermis

Rhomboidal-shaped gray-brown structures often seen in lentigo maligna

Asymmetric dark pigmentation around follicular openings; seen mainly in lentigo maligna

Light areas making up lines (cords) with dark “holes”; seen in Spitz nevi, dysplastic nevi, and melanoma

Brown-gray thickened lines within ridges of the skin (white dots also within ridge) seen in acral melanoma

Occurs late in invasive melanoma

Pigmented (blue-gray to brown-gray) ovoid structureless areas seen in pigmented BCC; represents heavily pigmented aggregations of basaloid cells in papillary dermis

Gray-blue leaf-like pattern; represents nests of pigmented BCC cells

Spoke wheel-like structures
(Figure 9.3B)

Tan to gray-blue radial projections, no pigment network

Arborizing vessels
(Figure 9.3A)

Thickened, discrete branching blood vessels (resemble branches of a tree); represents dilated arterial circulation feeding the tumor (rarely seen in intradermal nevi)

Occurs early in BCCs