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Facts about the skin from DermNet New Zealand Trust. Topic index: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z


Other algorithms for melanocytic lesions

Learning objectives
Introduction
ABCD rule
Menzies method
7-point rule
CASH acronym
CHAOS and clues
BLINCK algorithm
Activity

Learning objectives

Introduction

The first step algorithm identifies whether a lesion is melanocytic or nonmelanocytic. Various algorithms may be used to distinguish benign melanocytic lesions from malignant melanoma:

If these algorithms appear too complicated, use the 3-point checklist to identify malignant pigmented lesions.

ABCD rule

The ABCD rule (Stolz method) is used for the dermoscopic differentiation between benign melanocytic lesions and melanoma. The likelihood of melanoma depends on adding up the scores for different features as shown below.

Criteria Score  X   Factor  =   Results
Asymmetry
In perpendicular axes: contour, colours and structures
0 - 2 1.3 0 - 2.6
Borders
8 segments: abrupt ending of pigment pattern
0 - 8 0.1 0 - 0.8
Colours
White, red, light-brown (tan), dark-brown, blue-grey, black
1 - 6 0.5 0.5 - 3.0
Differential structural components or Dermoscopic structures (pigment network, structureless areas, dots, aggregated globules, branched streaks)
1 - 5 0.5 0.5 - 2.5
Total score Benign <4.76
Suspicious 4.76-5.45
Melanoma >5.45
Dermoscopy
Asymmetry = 0
Dermoscopy
Asymmetry = 1
Dermoscopy
Asymmetry = 2
Dermoscopy
Borders = 0
Dermoscopy
Borders = 4
Dermoscopy
Borders = 8
Dermoscopy
Colours = 1
Tan
Dermoscopy
Colours = 3
Tan, dark brown, black
Dermoscopy
Colours = 5
White, red, tan, dark brown, black

Blum's modified ‘ABC-point list’ is simpler to use:

Menzies method

Menzies method to distinguish the dermoscopic features of benign melanocytic lesions from melanoma.

Negative features (benign lesions):

Dermoscopy
Symmetrical pattern
Dermoscopy
Symmetrical pattern
Dermoscopy
Single colour
Dermoscopy
Single colour

Positive features (melanoma):

Dermoscopy
Blue-white veil
Dermoscopy
Multiple brown dots
Dermoscopy
Pseudopods
Dermoscopy
Radial streaming
Dermoscopy
Scar-like depigmentation
Dermoscopy
Multiple colours (5)
Dermoscopy
Multiple blue/grey dots
Dermoscopy
Broadened network

Seven-point rule

7-point checklist (Argenziano) for the dermoscopic differentiation between benign melanocytic lesions and melanoma (scores in brackets). The scores should be added up. Three or more indicates melanoma.

  1. Atypical pigment network (2)
  2. Blue-whitish veil (2)
  3. Atypical vascular pattern (2)
  4. Irregular streaks (1)
  5. Irregular dots/globules (1)
  6. Irregular blotches (1)
  7. Regression structures (1)

The seven-point rule has been revised (2011) so that each item scores 1 (total is 7). IN patients with atypical naevi, any lesion with a score of one should be carefully examined and excision of such lesions will pick up many early-stage melanomas.

Dermoscopy
Atypical pigment network
Dermoscopy
Blue-whitish veil
Dermoscopy
Atypical vascular pattern
Dermoscopy
Irregular streaks
Dermoscopy
Irregular dots/globules
Dermoscopy
Irregular blotches
Dermoscopy
Regression structures

C.A.S.H. acronym

C.A.S.H. (Kopf et al) is used for the dermoscopic differentiation between benign melanocytic lesions and melanoma (scores in brackets).

Suspicion for melanoma
Low Medium High
Colours: few vs many
Light brown, dark brown, black, red, white, blue
Score 1 point for each colour
1-2 colours (1-2 points) 3-4 colours (3-4 points) 5-6 colours (5-6 points)
Architecture: order vs disorder
Score 0-2 points
None or mild disorder (no points) Moderate disorder (1 point) Marked disorder (2 points)
Symmetry vs asymmetry
Consider contour, colours and structures
Score 0-2 points
Symmetry in 2 axes (no points) Symmetry in 1 axis (1 point) No symmetry (2 points)
Homogeneity vs Heterogeneity
Consider pigment network, dots/globules, blotches, regression, streaks, blue-white veil, polymorphous vessels
Score 1 point for each structure
Only one structure (1 point) 2 types of structure (2 points) 3 or more structures (3-7 points)

Add up the scores for a total C.A.S.H. score (2 to 17).

 C.A.S.H. in melanoma  C.A.S.H. in melanoma  C.A.S.H. in melanoma
C: 4 colours/points; A: marked disorder, 2 points; S: no symmetry, 2 points; H: 5 structures/points. Total=13 C: 5 colours/points; A: marked disorder, 2 points; S: no symmetry, 2 points; H: 4 structures/points. Total=13 C: 4 colours/points; A: marked disorder, 2 points; S: no symmetry, 2 points; H: 2 structures/points. Total=10
 C.A.S.H. in melanoma  C.A.S.H. in melanoma  C.A.S.H. in melanoma
C: 4 colours/points; A: marked disorder, 2 points; S: no symmetry, 2 points; H: 3 structures/points. Total=11 C: 3 colours/points; A: moderate disorder, 1 point; S: no symmetry, 2 points; H: 3 structures/points. Total=9 C: 4 colours/points; A: marked disorder, 2 points; S: no symmetry, 2 points; H: 4 structures/points. Total=12
C.A.S.H. in melanoma

CHAOS and clues

A modified form of pattern analysis (Kittler, Rosendahl et al) looks for CHAOS (asymmetry of structure and/or colour) and at least one clue to diagnose malignancy. It can be applied to melanocytic and non-melanocytic lesions.

Patterns are described by multiple elements of the same type: lines, dots, clods, circles, pseudopods (a line with a bulbous end) and structureless areas. Structureless areas are made up of colours: black, dark brown, light brown, grey, blue, orange, yellow, white, red and purple.

Symmetrical dermoscopic pattern Symmetrical dermoscopic pattern Symmetrical dermoscopic pattern Symmetrical dermoscopic pattern
Symmetrical dermoscopic pattern Symmetrical dermoscopic pattern Symmetrical dermoscopic pattern Symmetrical dermoscopic pattern
Symmetry of structure

Asymmetrical patterns should lead to looking for specific clues to malignancy. The clues to malignancy (melanoma and no-nmelanocytic tumours) are:

  1. Thick reticular lines
  2. Grey or blue structures of any kind
  3. Pseudopods or radial lines at the periphery
  4. Black dots in the periphery
  5. Eccentric structureless area of any colour
  6. Polymorphous vascular pattern
  7. White lines
  8. Parallel lines on ridges
All images display CHAOS. Clues to malignancy are described under each lesion (numbered as above).
CHAOS and clues in melanoma CHAOS and clues in melanoma CHAOS and clues in melanoma Asymmetrical dermoscopic pattern
Clues: 2, 5 Clues: 1, 5 Clues: 5, 6 Clues: 2, 5, 6
CHAOS and clues in melanoma CHAOS and clues in melanoma CHAOS and clues in melanoma Asymmetrical dermoscopic pattern
Clues: 1, 2, 3, 4, 5, 6 Clues: 1, 4, 5 Clues: 1, 5, 6 Clues: 1, 2, 5, 7
CHAOS and clues in melanoma

Some of these images are poor quality, but the algorithm still works.

The BLINCK algorithm

The BLINCK algorithm has been devised to identify malignant lesions, particularly nodular melanoma, as this tumour often lacks conventional dermatoscopic features. It can also be used for nonmelanocytic lesions.

Benign If not, then consider the following:
Lonely An ugly duckling Score 1
Irregular Asymmetrical pigmentation pattern or >1 colour Score 1
Nervous Nervous patient OR changing lesion Score 1
Known Known clues to malignancy Score 1

Clues to malignancy are:

  1. Atypical network
  2. Segmental streaks
  3. Irregular black dots, globules, clods
  4. Eccentric structureless zone
  5. Irregular blue or grey colour
  6. Polymorphous, arborising, glomerular vessels
  7. Parallel ridge pattern or diffuse irregular brown/black pigmentation in acral lesion

A score of ≥2 requires biopsy.

No lesions are Benign; Some are Lonely. All are Irregular. Some are Nervous/changing. Known clues to malignancy are described under each lesion (numbered as above).
BLINCK in melanoma BLINCK in melanoma BLINCK in melanoma
Clues: 4, 5 Clues: 3, 4 Clues: 3, 4
BLINCK in melanoma BLINCK in melanoma BLINCK in melanoma
Clues: 1, 3, 4 Clues: 2, 4 Clues: 1, 4
BLINCK in melanoma

Some of these images are poor quality, but the algorithm still works.

Activity

Find the evidence to support the use of the algorithms. Which is the best?

 

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Author: Clin Assoc Prof Amanda Oakley

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