Melanoma patterns and structures

From dermoscopedia

Main PageTwo-step algorithmMelanoma patterns and structures
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 Authored by: Ralph P. Braun     ·  Aimilios Lallas     ·  Ashfaq A. Marghoob

 Keywords:   melanoma · two-step algorithm
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Description This chapter describes dermoscopyThe examination of [skin lesions] with a 'dermatoscope'. This traditionally consists of a magnifier (typically x10), a non-polarised light source, a transparent plate and a liquid medium between the instrument and the skin, and allows inspection of skin lesions unobstructed by skin surface reflections. Modern dermatoscopes dispense with the use of liquid medium and instead use polarised light to cancel out skin surface reflections. pattern of melanomaThis glossary term has not yet been described. that require contextThis glossary term has not yet been described.
Author(s) Ralph P. Braun · Aimilios Lallas · Ashfaq A. Marghoob
Responsible author Ash Marghoob→ send e-mail
Status released
Status update July 2, 2018
Status by Ralph P. Braun


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MelanomaThis glossary term has not yet been described. patternsThis glossary term has not yet been described.:

Melanomas will usually manifest a disorganized distribution of structuresThis glossary term has not yet been described. and colorsThis glossary term has not yet been described. making their identification quite easy. These lesions will reveal at least one, but usually more than one, of the melanoma specific structures listed below. On rare occasions melanomas will present with a symmetric and organized pattern but these tumors will almost always reveal one of the following features: starburst patternThis pattern consists of peripheral globules, pseudopods or streaks (or a combination of them), located around the entire perimeter of the lesion, negative networkSerpiginous interconnecting broadened hypopigmented lines that surround elongated and curvilinear globules., blue-black or gray colorColor (American English) or colour (Commonwealth English) is the characteristic of human visual perception described through color categories, with names such as red, yellow, purple, or blue., shiny white structuresThis glossary term has not yet been described., vesselsThis glossary term has not yet been described. or ulceration.

A few melanoma patterns deserve special mention.
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  • Featureless or structureless (non-specific or feature poor) lesions are lesions that have no dermoscopic structuresThis glossary term has not yet been described. or do have dermoscopic structures but the structures present cannot be used to differentiate benignis any condition that is harmless in the long run from malignantThis glossary term has not yet been described.. If such lesions are non-palpable then they can be digitally monitored or can be biopsied. If such a lesion is palpable then digital monitoring is contraindicated and the lesion should be biopsied.
  • Melanoma should be in the differential diagnosisis the identification of the nature and cause of a certain phenomenon. Diagnosis is used in many different disciplines with variations in the use of logic, analytics, and experience to determine "cause and effect". In systems engineering and computer science, it is typically used to determine the causes of symptoms, mitigations, and solutions for any blue-black nodule.
  • Melanoma in situThis glossary term has not yet been described. can manifest a pattern comprised of small foci of hyperpigmentation. The hyperpigmented areas differ from blotches in that they are small (cover <10% surface area), multiple and do not obscure the ability to see underlying structures. These melanomas will also often reveal prominent skin markings.
  • Melanoma on sun damaged non-facial skinThis glossary term has not yet been described. (lentigo malignaThis glossary term has not yet been described.) is associated with the following patterns: patches of peripheral networkThis glossary term has not yet been described. islands, tan structureless areas with granularityThis glossary term has not yet been described., and a lesion with angulated linesSyn: polygons, zig-zag pattern Gray-brown lines that are connected at an angle or coalescing to form polygons.

Melanoma specific structures:

StructuresThis glossary term has not yet been described.

Almost all melanomas will reveal at least one of the following structures/features:

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  • Atypical networkNetwork with increased variability in the color, thickness, and spacing of the lines of the network; asymmetrically distributed; gray color

Typical networkNetwork with minimal variability in the color thickness and spacing of the lines; symmetrically distributed consists of brown lines with minimal variability in their color and thickness. The holes of the network are of similar size. Atypical network consists of lines with increased variability in color and thickness. The atypical lines are often broadened, smudgy in appearance and often have a grayish color.

  • Angulated linesSyn: polygons, zig-zag pattern Gray-brown lines that are connected at an angle or coalescing to form polygons
  • Negative networkSerpiginous interconnecting broadened hypopigmented lines that surround elongated and curvilinear globules.
  • Atypical streakslines radial (always at periphery) streaks Reed nevus melanoma recurrent nevus

Typical streaks consist of streaks arranged symmetrically around the entire perimeter of the lesion as seen in Reed’s neviThis glossary term has not yet been described..
Atypical streaks consist of streaks that are only focally present at the periphery.

  • Atypical dots and globulesThis glossary term has not yet been described.

Typical dots consist of dots that are centrally located within an otherwise organized lesion or dots associated with a typical networkNetwork with minimal variability in the color thickness and spacing of the lines; symmetrically distributed. The typical dots associated with a typical network are located on the network lines or in the holes of the network. Any other manifestation of dots is considered atypical.
Atypical dots are distributed asymmetrically, are not clustered in the center and are associated with an atypical networkNetwork with increased variability in the color, thickness, and spacing of the lines of the network; asymmetrically distributed; gray color. Typical globules are those found in nevi described in step-1 of this algorithmIn mathematics and computer science, an algorithm (Listeni/ˈælɡərɪðəm/ AL-gə-ri-dhəm) is a self-contained sequence of actions to be performed. Algorithms can perform calculation, data processing and automated reasoning tasks.. Globules of similar shape, size and color distributed throughout the lesion (including cobblestone), at the periphery of an otherwise reticular nevusThis glossary term has not yet been described., or in the center of an otherwise reticular pattern nevus are considered typical.
Any other manifestation of globules would be considered atypical.

  • Peripheral tan structureless areas
  • Atypical blotches

Typical blotchDark structureless areas consists of one round to oval homogeneous blotch in the center of an otherwise reticular pattern nevus.
Atypical blotch consists of an off center blotch or the presence of multiple blotches. The blotches can have irregular shapes and hues.

  • Multiple small hyperpigmented areas of irregular shape
  • Accentuated skin markings
  • Blue-white veil over raised areas
  • Regression structuresThis glossary term has not yet been described. (flat, non-palpable areas)
  • GranularityThis glossary term has not yet been described. / pepperingGray dots
  • Scar like depigmentation
  • Blue-white veil over flat area
  • Shiny white linesstreaksThis glossary term has not yet been described.

Atypical vessels

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  • Comma vesselslinear curved short vessels dermal nevi in flat lesions (not IDNThis glossary term has not yet been described.)
  • Dotted vesselstiny pinpoint vessels
  • Serpentine or linear vesselsLinear mildly curved vessels considered irregular when different sizes shapes and curves with a haphazard or random distribution are presented and considered regular when short and fine (thin) linear vessels prevail various diagnoses
  • Milky red areasMilky-white appearance or pinkish structureless areas ("strawberry and ice cream"-like), consisting a red vascular blush with no specific distinguishable vessels and globules
  • Polymorphous pattern - The most common pattern is one with both dotted and serpentine vesselslinear irregular vessels with multiple bends. Seen with flat BCC and melanoma
  • Corkscrew vesselstwisted looped vessels with bends twisted along a central axis melanoma metastasis