To calculate the ABCD
score, the 'Asymmetry, Border, Colors, and Dermoscopic structures'
criteria are assessed semiquantitatively.
Each of the criteria is then multiplied by a given weight factor to
yield a total dermoscopy score (TDS).
TDS values less than 4.75 indicate a benign melanocytic lesion,
values between 4.8 and 5.45 indicate a suspicious lesion, and values
of 5.45 or greater are highly suggestive of melanoma.
Asymmetry
To assess asymmetry,
the melanocytic lesion is bisected by two 90º axes that were
positioned to produce the lowest possible asymmetry score. If both
axes dermocopically show asymmetric contours with regard to
shape, colors and/or dermoscopic structures, the asymmetry score is
2.
If there is asymmetry on one axis only, the score is 1. If asymmetry
is absent with regard to both axes the score is 0.
Border
The lesion is divided
into eighths, and the pigment pattern is assessed. Within each
one-eighth segment, a sharp, abrupt cut-off of pigment pattern at
the periphery receives
a score 1. In contrast, a gradual, indistinct cut-off within the
segment receives a score
of 0. Thus, the maximum border score is 8, and the minimum score is
0.
Color
Six different colors
are counted in determining the color score: white, red, light
brown,
dark brown, blue-gray, and black. For each color present, add +1 to
the score.
White should be counted only if the area is lighter than the
adjacent skin.
The maximum color score is 6, and the minimum score is 1.
Dermoscopic structures
Evaluation of
dermoscopic structures focuses on 5 structural features: network,
structureless (or homogeneous) areas, branched streaks, dots, and
globules.
The presence of any feature results in a score +1 Structureless (or
homogenous) areas must be larger than 10% of the lesion to be
considered present. Branched streaks and dots are counted only when
more than two are clearly visible. The presence of a single globule
is sufficient for the lesion to be considered positive for globules.
Criterion
Description
Score
Weight
factor
Asymmetry
In 0, 1, or 2 axes; assess not
only contour, but also colors and structures
0-2
X 1.3
Border
Abrupt ending of pigment pattern
at the periphery in 0-8 segments
0-8
X 0.1
Color
Presence of up to 6 colors (white,
red, light brown, dark brown, blue-gray, black)
1-6
X 0.5
Dermoscopic structures
Presence of network, structureless
or homogeneous areas, branched streaks, dots, and globules
1-5
X 0.5
Formula for TDS: [ (A score x
1.3) + (B score x 0.1) + (C score x 0.5) + (D score x 0.5) ]
Total Dermoscopy Score (TDS)
Interpretation
<4.75
Benign melanocytic lesion
4.8-5.45
Suspicious lesion; close follow-up
or excision recommended
>5.45
Lesion highly suggestive of
melanoma
False-positive score (>5.45)
sometimes observed in:
Reed and Spitz nevus
Clark nevus with globular
pattern
Congenital melanocytic
nevus
A = 0 (x 1.3);
B = 8 (x0.1);
C = 2
[light-brown, dark-brown]
(x 0.5);
D = 2
[network, globules]
(x 0.5)
--- TDS = 2.8 (benign) ---
Histopathologic diagnosis: Clark nevus
A = 1 (x 1.3);
B = 4 (x 0.1);
C = 3
[light-brown, dark-brown, black]
(x 0.5);
D = 2
[network, dots]
(x 0.5)
--- TDS = 4.2 (benign) ---
Histopathologic diagnosis: Clark nevus
A = 2 (x 1.3);
B = 5 (x 0.1);
C = 5
[light-brown, dark-brown, blue-gray, black, white]
(x 0.5);
D = 4
[homogeneous areas, streaks, dots, globules]
(x 0.5)
--- TDS = 7.6 (malignant) ---
Histopathologic diagnosis: melanoma
A = 0 (x 1.3);
B = 0 (x 0.1);
C = 2
[light-brown, dark-brown]
(x 0.5);
D = 2
[network, dots]
(x 0.5)
--- TDS = 2.0 (benign) ---
Histopathologic diagnosis: Clark nevus
A = 2 (x 1.3);
B = 3 * (x 0.1);
C = 4
[light-brown, dark-brown, blue-gray, black]
(x 0.5);
D = 4
[network, streaks, dots, globules]
(x 0.5)
--- TDS = 6.9 (malignant) ---
Histopathologic diagnosis: melanoma
A = 2 (x 1.3);
B = 3 * (x 0.1);
C = 4
[light-brown, dark-brown, blue-gray, black]
(x 0.5);
D = 4
[network, homogeneous areas, streaks, globules]
(x 0.5)
--- TDS = 6.9 (malignant) ---
Histopathologic diagnosis: melanoma
