Chaos and clues
From dermoscopedia
- 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.
Chaos
- 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).
- Eccentric structureless area: any color except skin color.
- Gray or blue structures: Gray dots may be seen in pBCC and pBD as well as melanoma. Gray circles occur in noninvasive facial melanomas.
- Black dots or clods, peripheral: They are generally produced by melanoma cells or nests, respectively.
- 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.
- 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.
- White lines: To qualify as a clue, they must be clearly lighter than perilesional skin.
- 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.
- Lines parallel, ridges (acral skin): Clue to malignancy even in the absence of chaos. Subcorneal hemorrhage also produces this pattern.
