Argon laser treatment of lentiginosis 
Therapeutic report 
LENTIGINOSIS IN 
QUADRANT DISTRIBUTION. 
SUCCESSFUL TREATMENT 
WITH ARGON LASER 
D . Kopera and H. P. Soyer 
SUMMARY 
A 34-year-old woman with numerous lentigines in a quadrant distribution scattered over the lower right 
portion of her body is presented. Removal of multiple lentigines may be crucial. A safe and effective method 
far the removal of multiple lentigines is shown. Differential diagnoses of this unusual distribution pattern of 
lentigines are discussed. Argon laser treatment has been initiated far the management of this pigmentary 
disorder far cosmetic reasons. Lentigines faded within 4 weeks after application of 2 to 4 argon laser light 
impulses each. 
Quadrant distribution of skin lesions represents a rare pattern due to mosaicism in early embryogenesis. 
Treatment of lentigines with argon laser can be regarded as an effective approach in the management of 
multiple lentigines leading to an excellent cosmetical result. 
KEY WORDS 
lentiginosis, treatment, argon laser 
INTRODUCTION 
Simple lentigines are clinically characterized as 
small, rather sharply circumscribed brownish-black 
macules on otherwise regular skin. They are generally 
regarded as precursors of junctional melanocytic 
nevi (1,2). Usually simple lentigines appear scattered 
over trunk and extremities of younger individuals 
with increased susceptibility to sunburn. Besides this 
classical pattern, numerous simple lentigines may 
rarely occur in peculiar distributions, namely genera-
lized (e.g. leopard syndrome), grouped (agminated), 
66 
or segmenta! (zosterifarm) (Tab. 1) (3-8). These 
unusual variants of lentigines, commonly called 
lentiginosis, should be clearly distinguished from 
lentiginous lesions arising on the diffuse brownish 
background of a preexisting nevus ( e.g. speckled 
nevus) (9). 
We report on a female presenting multiple .simple 
lentigines and faur melanocytic nevi scattered over 
the lower right quadrant of her body with special 
emphasis on the treatment modalities. 
acta dermatovenerologica A.P.A. Vol 6, 97, No 2 
Argon laser treatment of lentiginosis 
PATIENT AND METHODS 
Report of a case. 
A 34-year-old woman presented with numerous 
lentigines in unusual distribution. At the age of 5, 
"freckles" on her right leg and the lower right 
portion of the trunk were first noticed by her 
mother. At the same tirne larger whitish patches 
occurred on the neck, right hip and bust. Familial 
history revealed no pigmentary anomalies within the 
last three generations. Clinically numerous brownish-
black macules up to 2 mm in diameter were scattered 
over the lower right quadrant of her skin. The 
"spotted" skin was rather sharply demarcated against 
the rest of the body: from the pubic area to the 
navel, and like a belt around the body to the spine, 
ending in the crena ani (Fig. 1). In addition to the 
numerous lentigines four slightly elevated brown 
lesions with a diameter of 5 mm were situated on 
.. "'· "'. :·. 
·' 
' ·, 
Figure l. Lentiginosis in quadrant distribution: 
Small, non-elevated brownish-black macules up to 2 
mm in diameter scattered over the right thigh. 
acta dennatovenerologica A.P.A. Vol 6, 97, No 2 
the right thigh and on the right suprapubic area. 
Only very few lentigines were present on the other 
body regions. Besides these pigmented lesions, some 
depigmented patches of 4 cm in diameter were 
present on the neck, on the right hip and on the 
chest. 
Histopathology 
Punch biopsies of three small lentigines and one 
white patch were obtained, all four larger pigmented 
lesions were excised totally. 
All three lentigines were histopathologically similar 
and were characterized by a moderately dense melanin 
pigmentation of the basal cell layer. A slightly 
increased number of typically appearing melanocytes 
was present in the basal layer of sections from all 
three specimens. Also in serial sections nests of 
melanocytes could not be observed. No giant melano-
somes were present. Based on these histopathologic 
Figure 2. 
Four months after argon laser treatment of lentiginosis. 
67 
Argon laser treatment of lentiginosis 
Table l. Disorders characterized by numerous lentigines 
Carney syndrome 
Centrofacial lentiginosis (Touraine, Greither) 
Generalized lentigo 
Lentiginous mosaicism 
Lentiginosis perigenito-axillaris 
Lentiginosis profusa syndrome (leopard) 
Lentiginosis with hemangiomas (Bandler) 
Lentiginosis with nystagmus and strabismus (Pimkin) 
Multiple lentigines syndrome 
Partial unilateral lentiginosis 
Periorificial lentiginosis (Peutz-J eghers) 
Pigmented unilateral nevus-like lentigo 
Syndrome of peptic ulcer/hiatal hernia, multiple 
lentigines, cafe-au-lait spots, hypertelorism, myopia 
Tay's syndrome 
features the diagnosis of simple lentigo was established. 
The larger pigmented lesions were diagnosed as 
Clark's nevi, compound type, according to the histo-
pathologic criteria set forth by A. B. Ackerman (1) . 
Histopathologic examination of a punch biopsy 
specimen from a depigmented patch on the right 
hip showed absence of epidermal melanin and a 
very sparse perivascular lymphohistiocytic infiltrate. 
The histopathologic findings were in accordance 
with the clinical diagnosis of vitiligo. 
Argon laser treatment. 
An argon laser [Cooper Medical Model 25] has 
been used in a single pulse mode. Spot size was 1 
Table 2. Lentiginous lesions within a preexisting nevus 
Mosaic speckled nevus 
N aevus spilus tardus (Becker, s nevus) 
Speckled nevus 
Speckled lentiginous nevus 
Speckled zosteriform lentiginous nevus 
Zosteriform lentiginous nevus 
68 
mm and pulse duration 0.5 sec, at a power level of 
1.5W. In 10 sessions all lentigines were exposed to 
2 to 4 overlapping argon laser light impulses each. 
Anesthesia was not required. 
Immediately after argon laser exposure a 4 mm 
biopsy specimen showed partial epidermal necrosis 
and a moderately dense mixed cell infiltrate in the 
upper dermis. 
RESULTS 
Clinical outcome after argon laser treatment 
Four months after the fina! laser treatment the 
formerly "freckled" lower right quadrant of the 
patient's skin exhibited almost the same homogenous 
complexion as the surrounding normal skin (Fig. 2). 
A now obtained biopsy specimen revealed only 
slight fibrosis of the papillary dermis and a normal 
melanocyte number without increased melanin 
pigmentation of the basal layer. Recurrent pigmentation 
could not be observed in a follow-up period of 
three years. 
DISCUSSION 
Our patient presented with a peculiar variant of 
systemized lentigines, namely numerous small brownish-
black macules scattered over the distal right quadrant 
of her body histopathologically revealing the features 
of lentigo simplex. In addition, four melanocytic 
compound nevi, Clark's type (formerly called dysplastic 
nevi), were observed within this area supporting the 
concept that simple lentigines actually may represent 
precursor lesions of melanocytic nevi (10). 
Lentiginosis in regional distribution on otherwise 
normal skin has been previously described attributing 
various denominations (Tab. 1) (3-8). Lentiginous 
lesions within the diffuse brownish background of a 
pre-existing nevus have to be carefully distinguished 
as differential diagnoses (Tab. 2) (9). In our view, 
the term "lentiginosis in quadrant distribution" reflects 
best the clinical description of the findings in our 
patient. 
The peculiar distribution of the lentigines found 
in this patient is quite comparable to the pattern in 
a patient reported by Sterry and Christophers. Their 
patient, however, presented multiple dysplastic nevi 
(Clark's nevi) and two malignant melanomas in a 
quadrant distribution (11). The quadrant manifostation 
of the skin lesions in the patient presented here 
may be explained by somatic mutation early in 
ontogeny causing mosaicism (12). In the management 
acta dermatovenerologica A.P.A. Vol 6, 97, No 2 
Argon laser treatment of lentiginosis 
of multiple lentigines thorough investigation has to 
exclude the presence of associated symptoms, such 
as cardiac myxomas, gastrointestinal neoplasms and 
organ dysplasias as found in Carney syndrome, 
leopard syndrome, or periorificial lentiginosis (Tab. 
1). 
The treatment of multiple lentigines may be difficult, 
because surgical excision or punching is not suitable 
for a large number of lesions, as scars have to be 
expected. Chemical peeling represents a technique 
able to remove superficial epidermal pigmentation, 
but does not affect pigments of the basal cell layer 
and of the papillary dermis. The application of 
liquid nitrogen promises the achievement of good 
cosmetical results and can be seen as an alternative 
type of treatment. 
In our patient we chose the argon laser for the 
removal of multiple lentigines utilizing the advantages 
of the selective absorption spectrum of melanin 
representing the major absorber of light (wavelengths: 
320 nm-1000 nm) in the epidermis. Thus, different 
types of high energy laser systems have been employed 
for the photothermic destruction of skin pigmentation. 
Blue-green argon laser light (main output at wave-
lengths 488 nm and 514 nm) is highly absorbed by 
melanin and hemoglobin and is able to destroy 
these pigments selectively. Thermal injury of non-
cromophoric connective tissue is minimal. Subsequent 
healing without major clinical evidence of scarring is 
the rule (13). New pigmentation appearing several 
years after argon laser therapy of pigmented lesions 
has been reported reinforcing the necessity for careful 
long tirne follow-up (14). Due to the specific absorption 
of argon laser light by melanin, this source has 
been used instead of the rather unspecific thermal 
destruction achieved by the carbon dioxide laser, 
emitting invisible infrared light (wavelength 10600 
nm) mainly absorbed by water (15) . In melanocytic 
lesions recurrence has also been reported following 
carbon dioxide laser treatment. Histopathological 
classification of recurrent nevi may be difficult and 
reveal pseudomelanoma. The q-switched ruby laser 
(wavelength 694 nm) produces a high peak power 
output with a pulse duration in the nanosecond 
range and is able to provide selective melanosomal 
damage without affecting surrounding tissue structures. 
Clearing of pigmented lesions has been reported 
following experimental ruby laser application (16, 
17). 
In our patient, argon laser treatment led to a 
highly satisfying result in esthetic terms (Fig. 2). 
Recurrent pigmentation could not be observed in a 
follow-up period of three years. 
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AUTHORS' ADDRESSES 
Daisy Kopera MD, Department of Dermatology, University of Graz, Auenbruggerplatz 8, · 
A- 8036 Graz, Austria 
Hans Peter Soyer MD, professor of dermatology, same address 
acta dermatovenerologica A.P.A. Vol 6, 97, No 2