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Am Fam Physician. 2013;88(7):1-6

Dermoscopic structuresSchematic illustrationDefinitionHistopathologic correlation
Pigment networkGrid-like network consisting of pigmented lines and hypopigmented holesMelanin in keratinocytes or melanocytes along the dermoepidermal junction
Network lines correspond to the rete ridges
Holes correspond to the suprapapillary plate
PseudonetworkDiffuse pigmentation interrupted by adnexal openingPigment in the epidermis or dermis in which the rete ridges are attenuated
Usually seen in facial lesions
Negative pigment networkSerpiginous interconnecting hypopigmented lines that surround irregularly shaped pigmented structures resembling elongated curvilinear globulesRemains unknown
Presumed to be related to bridging of rete ridges or large melanocytic nests in the papillary dermis, resulting in compression of adjacent rete ridges; these nests may correspond to globules that are not spherical in shape
Aggregated globulesMore than three clustered, well- demarcated, round to oval, symmetric structures, or three or more of these structures aligned at the lesion's perimeterNests of melanocytes at the dermoepidermal junction
May be brown, black, or blue
Diameters are greater than 0.1 mm
DotsSmall, round structures of less than 0.1 mm in diameterAggregates of melanocytes or melanin granules
May be black, brown, or blue-gray
Streaks (pseudopods and radial streaming)Streaks are radial projections at the periphery of the lesion, extending from the tumor toward the surrounding normal skin; may be brown or blackConfluent junctional nests of melanocytes
Pseudopods are streaks with finger-like projections with small knobs at the tips
Radial streaming is streaks without knobs at the tips
Peppering (or granularity)Tiny, blue-gray granulesMelanin deposited as intracellular (mostly within melanophages) or extracellular particles in the upper dermis
Structureless areasDevoid of dermoscopic structures within the lesion and without manife sting any regression structuresRelative decreased concentration of melanin or flattening of rete ridges
Tend to be tan to light brown, but have lighter pigment compared with the rest of the lesion
Peripheral light brown or tan structureless areasStructureless areas (as above), located at the periphery of the lesionPartial or complete flattening of the rete ridges
Increased number of pigmented atypical melanocytes predominantly at the dermoepidermal junction
Diffuse scattering of melanocytes in the spinous layer of the epidermis
BlotchesDark brown to black homogeneous areas of pigment that obscure visualization of any other structuresAggregates of melanin in the stratum corneum or throughout all layers of the skin
Regression structuresInclude scar-like depigmentation (lighter than the surrounding uninvolved normal skin; appear shiny white under polarized dermoscopy) often combined with peppering; combination of scar-like depigmentation and peppering gives the appearance of a blue-white veilScar-like changes/white areas: thickened fibrotic papillary dermis
Blue areas: correlate with melanosis type of regression
Blue-white veilConfluent blue pigmentation with an overlying white ground-glass hazeAggregation of heavily pigmented melanocytes or melanophages in combination with compact orthokeratosis of the stratum corneum
White shiny structures (more conspicuous with polarized dermoscopy)Rosettes: appear as four white shiny points creating a pattern reminiscent of a four- leaf clover A4 Histopathologic correlation has not been fully explained
Crystalline structures: short, white, shiny linear streaks that are often parallel or orthogonal to each other A5, A6 Altered collagen or fibrosis in the dermis
White shiny areas: appear as larger structureless areas of shiny white colorAltered stromal matrix
Parallel pigment patternOn volar skin (i.e., palms and soles)Pigmented melanocytes in the furrows (crista limitants) or ridges (crista intermedia) on skin of palms and soles
Parallel rows of pigmentation following the furrows (as seen in nevi) or ridges (as seen in melanoma) of the dermatoglyphics
Dermoscopic structuresSchematic illustrationDefinitionHistopathologic correlation
Milia-like cystsRound whitish or yellowish structures that shine brightly (like “stars in the sky”) under nonpolarized dermoscopyIntraepidermal keratin-filled cysts
Further subclassified as small and starry, and as large and cloudy A9
Comedo-like openingsBlackhead-like plugs on the surface of the lesionConcave invaginations in the surface of the epidermis filled with keratin; some of these invaginations may correspond to follicular openings filled with keratin
Fingerprint-like structuresDelicate, thin, light brown parallel running lines that do not interconnect to form a gridEpidermal ridges
Gyri and sulciGyri (ridges or fat fingers) and sulci (fissures) that create a cerebriform surfaceEpidermal ridges with or without keratin filling the invaginations
These invaginations can be filled with keratin, creating crypts
Moth-eaten bordersConcave invaginations of the lesion border
Pigment network–like structureGrid-like pattern that can resemble the pigment network seen in a melanocytic neoplasmRidges, crypts, and comedo-like openings distributed in a manner that gives the appearance of a grid
Correspond to interconnecting epidermal ridges on the skin; the holes correspond to comedones or crypts
Lines tend to appear broader compared with the pigment network seen in nevi
Leaf-like structuresBrown to gray-blue discrete bulbous structures that may coalesce to create a shape that resembles a leafLarge pigmented basal cell carcinoma tumor nests in the upper dermis
Spoke wheel–like/concentric structuresWell-circumscribed brown to gray-blue-brown radial projections meeting at a darker brown central hubBasal cell carcinoma tumor nests radiating from the dermoepidermal junction
Large blue-gray ovoid nestsLarge, well-circumscribed ovoid areas; larger than globulesLarge basal cell carcinoma tumor nests in the dermis
Blue-gray globules or dotsMultiple, nonaggregated, round, well-circumscribed structuresSmall basal cell carcinoma tumor nests in the dermis
LacunaeRed (hemangioma), maroon (hemangioma and angiokeratoma), or black (angiokeratoma) lagoons often separated by septaeDilated vascular spaces
Dermoscopic structuresSchematic illustrationDefinition (morphology)Diagnostic associations
Glomerular vesselsCoiled vessels mimicking the glomerular apparatus of the kidneyBowenoid actinic keratosis, Bowen disease/squamous cell carcinomaA11,A13
Clear cell acanthoma
Hairpin vesselsU-shaped vesselsKeratinizing tumors such as keratoacanthoma and seborrheic keratosisA7,A11,A14
Not infrequently, may be twisted on its axis
Background: white halo common in keratinocytic tumors
U-shaped vesselsIrritated seborrheic keratosis, melanoma, basal cell carcinomaA15
Not infrequently, may be twisted on its axis
Background: pink halo or pink background common in irritated seborrheic keratosis, but can also be seen in cutaneous malignancies
Arborizing vesselsVessels with large diameter, branching irregularly into fine capillariesBasal cell carcinomaA11, A13
Can also be seen in cysts, furuncles, and other adnexal tumors
Crown vesselsBranching or nonbranching vessels radiating toward the center of the lesion but without crossing its centerSebaceous hyperplasiaA11
Molluscum contagiosum
Often associated with white/yellowish popcorn-like globular structures
Dotted or glomerular vessels in “string of pearls” or serpiginous distributionVessels distributed in a serpiginous patternClear cell acanthoma
Strawberry patternWhite-yellow follicular openings surrounded by a white halo, over a red backgroundActinic keratosisA16
Dermoscopic structuresSchematic illustrationDefinition (morphology)Diagnostic associations
Comma-shaped vesselsSlightly curved vesselsDermal nevi, congenital melanocytic neviA11
Dotted vesselsRed dots (0.01 to 0.02 mm)Spitz nevi, early melanoma (dotted over milky-red background)A11
Clark nevi (dotted over tan background)
Serpentine vesselsIrregular linear/undulating short vesselsMelanoma, congenital neviA11
Milky-red globules/vascular blushIll-defined globules of milky-red color and ill-defined areas of milky-red colorAmelanotic melanomaA11
Polymorphous vesselsCombination of two or more vessel morphologiesMelanomaA14
Most common combination is dotted and serpentine vessels
Corkscrew vesselsCoiled and tortuous vesselsCutaneous melanoma metastases, nodular melanoma, desmoplastic melanoma

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