Dermoscopic Detection of Melanoma on the Palms and Soles
Monday, July 30, 2012
The diagnostic technique of dermoscopy is widely used in the
clinical evaluation of pigmented and non-pigmented skin lesions.
Dermoscopic detection is particularly useful for the diagnosis of
melanoma in pigmented lesions on the palms and soles.1
The most common melanoma, in non-white populations, affecting
these anatomical sites is acral melanoma.2 Melanoma on the palms
and soles shows a unique dermoscopic pattern called the parallel
ridge pattern (PRP); this feature is diagnostically useful for
differentiating early melanoma from benign pigmented lesions at
these sites.3,4 In
this article, the dermoscopic evaluation of melanoma and other
pigmented lesions on the palms and soles is described.
Acral Melanoma on the Palms and Soles
Dermoscopic patterns characteristically observed in melanoma on
the palms and soles include the PRP, which exhibits band-like
pigmentation on the ridges of the surface skin markings (Figure 1a)
and irregular diffuse pigmentation (IDP), which shows structureless
pigmentation in variable shades of brown.4,5
The diagnostic sensitivity and specificity of the PRP are 86%
and 99%, respectively, not only in invasive melanoma but also in
in situ melanoma on the palms
and soles.4 This
highlights the importance of the PRP in distinguishing palmoplantar
melanoma in its early stages, when the melanoma is more likely to
be treated successfully.6
The specificity of IDP is comparable to that of the PRP. The
sensitivity of IDP in invasive palmoplantar melanoma is also very
high, at 97%. However, the sensitivity of IDP in in situ
melanoma in lower than that of the PRP, at 69%.4 This means that IDP
becomes more apparent in advanced lesions of palmoplantar
In more advanced palmoplantar melanoma, many other dermoscopic
findings seen in other subtypes of advanced melanoma are detected,
such as irregular dots/globules, irregular streaks, regression
structures, blue-white veil, and polymorphous vessels.3 However, an atypical
pigment network is rarely found in palmoplantar melanoma.
patterns seen in melanocytic lesions on the palms and soles. The
parallel ridge pattern (a) is characteristically detected in early
melanoma. The parallel furrow (b), lattice-like (c), and (d)
fibrillar patterns are major features observed in acquired
melanocytic nevus on the palms and soles.
Melanocytic Nevus on the Palms and Soles
The majority of melanocytic nevi observed on the palms and soles
are acquired nevi. Histopathologically, most of them are of
junctional or compound type with a minor intradermal component.
Major dermoscopic patterns seen in acquired melanocytic nevus on
the palms and soles include the parallel furrow pattern (PFP),
lattice-like pattern (LLP), and fibrillar pattern (FP) (Figure
The PFP is distinguished by parallel linear or curvilinear
pigmentation along the furrows of the skin markings.1 This pattern, observed
in 50-60% of palmoplantar nevi, is the prototype of the three major
dermoscopic patterns.7 In the LLP, transverse
pigmented lines bridging the parallel pigmented lines of the PFP
are seen, producing a lattice-like pigmentation pattern.1 This pattern is mainly
detected in acquired nevi, located on the arch areas of the sole
and peripheral portions of the palms and soles.8 The LLP is detected in
approximately 15% of palmoplantar nevi.
The FP exhibits densely packed, fine fibrillar pigmentation,
usually arranged in a direction crossing the skin markings.1 This pattern is caused
by the oblique arrangement of the thick cornified layer resulting
from mechanical pressure exerted through body
weight.8 The incidence of the FP is variable among
current studies, accounting for 6-21% of palmoplantar nevi.7 A combination of two
or three of these major patterns is not uncommon because LLP and FP
are anatomical or artifactual modifications of the PFP.7
In addition, dots/globules - mostly arranged on the ridges in a
regular fashion - can be detected in melanocytic nevus on the palms
and soles. It is worth noting that acral nevi located on the
transitional zones between the glabrous and non-glabrous skin or on
the interdigital areas occasionally show non-specific dermoscopic
patterns, eg densely packed linear or reticular pigmentation.
Histopathologically, these nevi on the transitional zones often
exhibit random proliferation of melanocytes within the epidermis,
mimicking the histopathologic features of melanoma.9
Dermoscopic features of congenital nevus on the palms and soles
are not essentially different from those of acquired nevus, with
PFP being the most common feature.10 However, a few
additional characteristic dermoscopic patterns are detected. One
such pattern is the crista dotted pattern, which shows multiple
globules arranged regularly on the ridges of the skin marking
Another is the "peas in a pod" pattern consisting of the PFP and
the crista dotted pattern (Figure 2b).10 In addition, rather
diffuse grayish blue pigmentation can be detected in congenital
palmoplantar nevus, reflecting the predominant intradermal
component commonly seen in congenital nevus.
Figure 2. Dermoscopic patterns seen in
congenital melanocytic nevus on the palms and soles: (a) the crista
dotted pattern and (b) the peas in a pod
Other Pigmented Lesions Showing the PRP or Similar
The PRP is a useful dermoscopic finding for detecting early
melanoma on the palms and soles. However, several conditions other
than melanoma also show the PRP or similar patterns on
For example, pigmented macules on the digits in Peutz-Jeghers and
Laugier-Hunziker syndromes exhibit the PRP.13 These syndromes can
be correctly diagnosed by their characteristic clinical features
such as multiple small macules on multiple digits and on the lip.
The PRP can also be detected in palmoplantar pigmentation induced
by drugs such as 5-fluorouracil, or in volar melanotic macules
mainly seen in black persons.11 Pigmented ridged
warts also shows dermoscopic features mimicking the PRP.14 This type of wart
must be carefully differentiated from the rare verrucous type of
Dermoscopic features of hemorrhage or hematoma on the palms and
soles are essentially the same as those seen in lesions on
non-glabrous skin, ie bluish-red or reddish-black homogeneous
areas. However, subcorneal hemorrhage in the acral skin sometimes
demonstrates a pebble-like appearance or band-like pigmentation on
the ridges of the skin markings, mimicking the PRP.11 Sharp demarcation and
a reddish hue of the pigmentation are differentiating features from
the authentic PRP. The PlayStation purpura, ie subcorneal purpura
of the fingers induced by repetitive friction with the controller
of computer game devices, also shows PRP-like pigmentation.16 Accidental staining
of the palmoplantar skin with a foreign body, such as
paraphenylendiamine or self-tanning products, could also
cause the PRP-like pigmentation.12
A Three-Step Algorithm for the Detection of Melanoma on the
Palms and Soles
Our study group has proposed a three-step algorithm for the
management of acquired melanocytic lesions on the palms and
soles,17 based on
our dermoscopic data and the 7 mm criterion we proposed
algorithm is shown in Figure 3.
Figure 3. A three-step algorithm for the management
of acquired melanocytic lesions on the palms and soles. Reproduced
with permission from Tanioka M et al. Clin Exp
One possible problem with this algorithm could be in the
evaluation of the regularity of the FP in the second step. Overall,
symmetric distribution of the fibrillar pigmentation is important
in the judgment of regular FP. Another indication of the regular FP
is that starting points of the fibrillar pigmentation are mostly
arranged in a linear fashion, corresponding to the furrows of the
We expect that, by using this algorithm, most palmoplantar
melanomas will be detected effectively in the early curable stages
and the number of unnecessary excision of benign nevi substantially
Using dermoscopy, we can effectively detect early melanoma on
the palms and soles based on the finding of the PRP, which differs
completely from the findings seen in melanocytic nevus at these
sites. Although several pigmented lesions on the palms and soles
can show the PRP or similar patterns, they are easily
differentiated from melanoma upon careful clinical and/or
- Ishihara K, Saida T, Otsuka F,et al. Statistical profiles of
malignant melanoma and other skin cancers in Japan: 2007 update.
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- Oguchi S, Saida T, Koganehira Y,et al. Characteristic
epiluminescent microscopic features of early malignant melanoma on
glabrous skin: a videomicroscopic study. Arch Dermatol.
- Saida T, Miyazaki A, Oguchi Set al. Significance of dermoscopic
patterns in detecting malignant melanoma on acral volar skin:
results of a multicenter study in Japan. Arch Dermatol.
- Kawabata Y, Tamaki K. Distinctive dermoscopic features of acral
lentiginous melanoma in situ from plantar melanocytic nevi and
their histopathologic correlation. J
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- Ishihara Y, Saida T, Miyazaki A,et al. Early acral melanoma in
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- Saida T, Koga H. Dermoscopic patterns of acral melanocytic
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- Miyazaki A, Saida T, Koga H,et al. Anatomical and
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- Saida T, Kawachi S, Koga H. Anatomical transition and the
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- Minagawa A, Koga H, Saida T. Dermoscopic characteristics of
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- Saida T, Koga H, Uhara H. Key points in dermoscopic
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- Tanioka M, Matsumura Y, Utani A, et al. Occupation-related
pigmented macules on the sole with parallel-ridge pattern on
dermoscopy. Clin Exp
- Sendagorta Cudos E, Feito Rodriguez M, Ramirez Marin P,et al.
Dermoscopic findings and histopathological correlation of the acral
volar pigmented maculae in Laugier-Hunziker syndrome. J Dermatol. 2010;37:980-984.
- Arpaia N, Filotico R, Mastrandrea V,et al. Acral viral wart
showing a parallel ridge pattern on dermoscopy. Eur J Dermatol.
- Dalmmau J, Abellaneda C, Puig S,et al. Acral melanoma
simulating warts: dermoscopic clues to prevent missing a melanoma.
- Robertson S, Leonard J, Chamberlain AJ. PlayStation
purpura. Australas J
- Koga H, Saida T. Revised 3-Step dermoscopic algorithm for the
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- Saida T, Yoshida N, Ikegawa S,et al. Clinical guidelines for
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