Chaos and clues

From dermoscopedia
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 Author(s): Harald Kittler
Description This chapter describes the chaos and clues approach
Author(s) Harald Kittler
Responsible author Harald Kittler→ send e-mail
Status unknown
Status update April 24, 2019
Status by Ralph P. Braun

  • It is designed to be applied to any pigmented skin lesion to rapidly detect any type of malignancy, or to guide the clinician in the decision whether a lesion should be excised or biopsied rather than to make a specific diagnosis.
  • The clinical and dermatoscopical examination for chaos is being defined as asymmetry of structure or color.
  • When chaos is discovered, the lesion is being searched for one of eight clues to malignancy.
  • If there are both chaos and at least one clue to malignancy then biopsy is indicated.


  • Definition: asymmetry produced by the pattern of structures or colors within a lesion.
  • Any color other than skin color at the edge of a lesion (such as white) should be regarded as part of the lesion.
  • A lesion with one pattern and one color, regardless of its shape, is symmetrical and therefore does not exhibit chaos. If any line drawn through the center of a lesion has different colors or structures on opposite sides it is asymmetrical and exhibits chaos.
  • Lesions without chaos are not analyzed any further.
  • It is very rare to find perfect symmetry in nature. If a decision cannot be made the lesion should be assessed as exhibiting chaos.

Clues to Malignancy

  • Definition: a feature which indicates that a lesion requires a biopsy to exclude malignancy. One clue is sufficient.
  • There are eight clues to pigmented malignancy (melanoma, pigmented basal cell carcinoma (pBCC), and pigmented Bowen’s disease (pBD).
  1. Eccentric structureless area: any color except skin color.
  2. Gray or blue structures: Gray dots may be seen in pBCC and pBD as well as melanoma. Gray circles occur in noninvasive facial melanomas.
  3. Black dots or clods, peripheral: They are generally produced by melanoma cells or nests, respectively.
  4. Lines radial or pseudopods, segmental: Lines radial may be seen at any location in BCC. Pseudopods or lines radial when circumferential area feature of Reed nevus, but if segmental they are highly specific for melanoma.
  5. Polymorphous vessels: Vessels are called polymorphous when more than one pattern of vessel is seen. They reflect disordered malignant growth pattern and possibly increased metabolic demand of actively growing tumor tissue.
  6. White lines: To qualify as a clue, they must be clearly lighter than perilesional skin.
  7. Lines reticular or branched, thick: To be called thick, the lines must be thicker than the spaces they surround. They are produced by melanoma cells.
  8. Lines parallel, ridges (acral skin): Clue to malignancy even in the absence of chaos. Subcorneal hemorrhage also produces this pattern.

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