ARTICLE
Auteur(s) :, Sangeun Kim, Won Hyoung Kang*
Department of Dermatology, Ajou University School of Medicine, 5
Wonchondong, PaldalKu, Suwon, Korea, 442721
accepté le 31 Août 2004
Congenital melanocytic nevi are nevomelanocytic nevi
apparent at birth and are present in 1-2% of newborn infants.
Congenital melanocytic nevi typically appear as sharply demarcated
plaques with or without coarse hairs and are solitary in 95% of
individuals. These nevi are measured by the largest diameter and
classified as small (< 1.5 cm), medium (1.5-19.9 cm), and large
or giant (> 20 cm). Although congenital nevomelanocytic nevi are
histologically compound or intradermal, they may differ from
acquired nevi by one or more features [1]. For example, nevus cells
of congenital melanocytic nevi are present around and within hair
follicles, in sweat ducts and glands, in sebaceous glands, in
vessel walls, and in the perineum of nerves, and they extend
between collagen bundles in single or double rows, as well as into
the deepest reticular dermis or subcutis. In contrast, nevus cells
of acquired nevi do not possess these characteristics.It is
difficult to remove congenital melanocytic nevi without scarring.
Thus, the main problem in the treatment of these nevi is to obtain
cosmetically good results. At times, removal of these congenital
nevi may produce cosmetic deformities with related psychological
problems. Without treatment, however, there is increased potential
for malignant degeneration. It has been estimated that 6-12% of
giant nevi undergo malignant transformation, compared with 1-3% of
medium and small nevi [2]. There is also the risk of recurrence.A
variety of treatment options have been utilized to treat congenital
melanocytic nevi, including skin graft after surgical excision [3,
4], chemical peeling [5], cryotherapy (liquid nitrogen, dry ice),
and dermabrasion [6, 7]. Although skin grafting after total
excision has been shown to remove the lesion with low recurrence,
it yields cosmetically poor results. Carbon dioxide lasers can
vaporize nevus cells, but they also vaporize surrounding normal
tissue, resulting in post treatment scarring during the removal of
medium to large nevi. For both of these methods, cosmetic results
may be less than desirable, especially for facial lesions where
hypertrophic scarring, hypo/hyperpigmentation, or atrophy remain
worrisome complications.Recently, Q-switched mode lasers have been
utilized to treat many pigmentary lesions, including nevi of Ota
[8-10], lentigines, café au lait macules [11] and benign
melanocytic nevi [12]. Because of their short pulse duration (1-100
ns), these lasers allow selective destruction of pigment-laden
cells while sparing the surrounding normal tissues. Because
Q-switched laser treatment of benign pigmented lesions has a low
potential for scarring, it has aroused the interest of physicians
who treat patients with congenital melanocytic nevi. Although the
Q-switched ruby laser (QSRL) and the Q-switched
neodymium:yttrium-aluminum-garnet laser (QSYAGL) have been used to
treat congenital nevi, [13-19] the Q-switched alexandrite laser
(QSAL) was tested just in one patient [20]. We therefore evaluated
use of the QSAL in the treatment of congenital melanocytic nevi.
Material and methods
Patients
From June 1996 through October 2002, 53 patients with congenital
nevi, ranging in age from 3 months to 45 years (average age, 8.9 ±
9.8 years) were retrospectively recruited from the Department of
Dermatology at Ajou Medical Center. In 42 patients, diagnosis was
confirmed by biopsy, whereas in the other 11, diagnosis was
confirmed by clinical findings and patient history.
Laser treatment regimen
The QSAL (Tatoo laser, Candela laser Co, model TL1) had a pulse
duration of 100 ns and wavelength of 755 nm. It was used at a
fluence of 8.0 J/cm2, with a spot size of 3 mm. The
interval between treatments ranged from 1 to 6 months. The average
number of QSAL treatments per patient was 3.9, with a range of 1 to
10. Of the 53 patients, 16 also received CO2 laser
treatments (Sharplan Inc.) with super-pulsed mode, 2 watts in the
intervals between QSAL treatments. The average number of
CO2 laser treatments was 2.5, with a range of 1 to 4.
Clinical assessment
Photographs were taken before and at 2 to 3 months after treatment
and at each follow up visit. Clinical improvement was based on
comparison of pre- and post-treatment (final visit) photographs of
the nevi.
For each patient, a clinical improvement score was obtained by
comparing, side by side, photographs of treated nevi to reference
photographs taken at baseline. Two blinded physician assessors
independently assigned a numeric score to each nevus on a scale of
0-4. The score was based on the percent improvement, with 0
corresponding to 0-20% improvement, 1 corresponding to 20-40%
improvement, 2 corresponding to 40-60% improvement, 3 corresponding
to 60-80% improvement, and 4 corresponding to 80-100%
improvement.
Complications evaluated included dyspigmentations and scar
formation. Dyspigmentation was described as hyperpigmentation or
hypopigmentation. Scar formation included textural changes,
depressions and hypertrophic scars. The duration of each
complication was recorded (over or under 2 months).
Results
Clinical assessment
Of the 53 patients treated, 25 were male and 28 were female. Their
ages ranged from 3 months to 45 years (mean, 8.9 ± 9.8 years;
median, 9 years). Forty-three of the nevi were on the face, five
were on the trunk, three were on the arm, and two were on the leg.
One patient had a giant nevus, 9 patients had medium-sized nevi,
and 5 patients had small-sized nevi.
The average clinical improvement score of these 53 patients was
2.623 ± 1.13, with 14 patients (26.4%) showing excellent results
(80-100%, score = 4) 48 weeks after 3 or more treatment sessions
(figures 1, 2 and 3). In contrast, only two patients (#4, #11)
showed no clinical improvement (score = 0), with one (#4) having
undergone 10 treatment sessions for a giant congenital nevus( ). The clinical
outcome of the 53 QSAL-treated patients is summarized in table 1(
Table 1 ).
We observed no significant differences in clinical improvement
score by age, with the 36 patients under 9 having an average
improvement score of 2.61 + 1.13 and the 17 patients over 9 having
an average improvement score of 2.65 ± 1.17 (p = 0.458).
We also observed no significant differences in clinical improvement
between patients having compound nevi (23/42, 55%) and those having
intradermal nevi (19/42, 45%) (2.52 ± 1.27 vs. 2.50 ± 1.02; p =
0.391. t test) or between those having deep nevi (> 1.5 mm;
13/42, 31%) and those having shallow nevi (< 1.5 mm; 29/42,
69%) (2.56 ± 1.22 vs. 2.50 ± 1.10; p = 0.46. t-test).
When compared with the 37 patients not treated with the
CO2 laser, the 16 CO2 laser treated patients
had significantly higher clinical improvement scores (3.0625 ±
1.1814 vs. 2.4324 ± 1.0682; p = 0.0393). According to the size of
nevus, there is no difference in the improvement score.
Table 1 Clinical improvement score of congenital nevi
after QSAL treatment
|
Score
|
% improvement
|
Number of patients (%)
|
|
0
|
0-20% (none)
|
2 (3.8%)
|
|
1
|
21-40% (minimal)
|
7 (13.2%)
|
|
2
|
41 60% (moderate)
|
14 (26.4%)
|
|
3
|
61-80% (good)
|
16 (30.2%)
|
|
4
|
81-100% (excellent)
|
14 (26.4%)
|
|
Total
|
|
53 (100%)
|
Complications of treatment
We observed only minor complications throughout these treatments,
including textural change (35/53, 66%) depressed scar formation
(2/53, 3.8%), and hypertrophic changes (4/53, 7.5%). Twelve
patients (23%) had a complete absence of these complications (table
2)( Table 2 ). Of the 41 changed nevi,
27 (66%) showed these changes for over 2 months. Changes in
pigmentation were observed in 32 nevi 48 weeks after the last QSAL
treatment, with 17 nevi showing hypopigmentation and 15 showing
hyperpigmentation (table 2), with these changes present for over 2
months in 13 of the 31 evaluable nevi. Absence of all complications
was observed in 6/53 (11%) patients. Repigmentation to a brown to
black spot was observed in 44/53 (83%) patients within an average
of 5.45 ± 3.93 months.
Table 2 Complications of QSAL treatment of congenital
nevi
|
Surface changes
|
Textural change
|
Depressed Scar
|
Hypertrophic scar
|
None
|
Total
|
|
Color changes
|
|
|
|
|
|
|
Hypopigmentation
|
10
|
1
|
1
|
5
|
17
|
|
|
|
|
|
(32.1%)
|
|
Hyperpigmentation
|
12
|
1
|
1
|
1
|
15
|
|
|
|
|
|
(28.3%)
|
|
None
|
13
|
0
|
2
|
6
|
21
|
|
|
|
|
|
(39.6%)
|
|
Total
|
35 (66%)
|
2 (3.8%)
|
4 (7.5%)
|
12 (22.7%)
|
53
|
|
(100%)
|
Discussion
Q-switched mode lasers are now being utilized to treat many pigment
lesions, including nevi of Ota [8-10], lentigines, café au lait
macules [11], and benign melanocytic nevi [12], because of their
short pulse duration (1-100 ns), allowing for selective destruction
of pigment-laden cells.
Because these lasers have shown a low potential for scarring
during the removal of benign pigmented lesions, they have been
tested in the treatment of congenital melanocytic nevi. Single
treatments of five congenital nevi with a QSRL or a QSYAGL,
however, was found to remove only their superficial portions [15],
suggesting that recurrence may have been due to residual dermal
nevomelanocytes. Using a QSAL, we observed no significant
differences in treatment score between compound and intradermal
nevi or between shallow and deep nevi. Measured from the top of the
papillary dermis, the maximum depth of destruction after a single
treatment was about 0.20 mm for the QSYAG and 0.40 mm for the QSRL.
Since the wavelength of QSAL is 755 nm, we estimate a maximum depth
of destruction after a single QSAL treatment of about 0.20-0.40 mm.
Thus, any difference between QSAL and the other types of Q switched
lasers was not due to nevus depth, but may have been due to the
degree of nevus cell nest reduction.
In evaluating the QSRL as a therapeutic option for small to
medium sized congenital nevi in 18 prepubertal children [14],
clinical lightening of pigmentation was noted between the first and
fourth treatments in all patients, with an average lightening of
57% after the fourth treatment. Following discontinuation of
therapy, however, 11 of these patients (81%) had partial
repigmentation within an average of 4.9 months. We noted similar
results in patients treated with the QSAL, in that, by the fourth
treatment session, there was an average improvement score (2.623)
corresponding to a lightening of 72%, while 44 of 53 patients (83%)
had partial repigmentation within an average of 5.5 months.
Treatment of a 2 year old Hispanic female with a QSRL [16]
resulted in complete removal of a biopsy-documented, medium-sized,
compound, congenital melanocytic nevus after the second treatment,
with no clinical recurrence after 5 years. Moreover, complications,
such as hypertrophic scarring, dyspigmentation, and atrophy, were
not observed. Although we observed no significance difference in
clinical improvement score between patients under 9 years old and
those over 9 treated with the QSAL, we observed transient excellent
results in one patient, who received 10 QSAL treatments, beginning
at 1 month old, for a giant congenital nevus, although there was
some repigmentation 3 months after the last treatment.
In comparing the effects of treatment with various Q-switch mode
lasers on congenital nevi (table 3)( Table
3 ), the QSRL was found to be effective in lightening the
nevi, but it was not able to completely eradicate nevus cell nests.
In addition, complications arising from use of the QSRL were not
reported. In treating congenital nevi with the QSAL, we observed
only minor complications.
Combined use of a normal ruby laser (NMRL) and a QSRL has been
found to be more effective than either alone, in reducing nevus
cell nests of congenital nevi [18]. The effective removal of
epidermis with the NMRL enabled penetration by the QSRL to a
greater degree. Moreover, the NMRL may be more effective than the
QSRL in destroying the nevus cells themselves. We used the
CO2 laser for additional treatment of thick or reccuring
lesions after a previous session. Our finding, that the combination
of a QSAL and a CO2 laser was more effective than a QSAL
alone, provides additional evidence that combination treatment may
be better than treatment with a single laser.
In a comparison of a QSAL and a QSYAGL in the treatment of
benign melanocytic nevi [12], both laser systems resulted in
significant improvement (lightening) of treated nevi, although the
QSAL produced slightly better global assessment scores.
In conclusion, we have shown that the QSAL was as effective as
other Q-switched lasers in providing clinical improvement without
severe complications in the treatment of congenital melanocytic
nevi. Repeated treatments with the QSAL provided cosmetic benefit
by reducing the pigmentation of congenital nevi without severe
complications. These findings suggest that QSAL treatment may be an
alternative therapeutic option for the treatment of congenital
nevi, but repigmentation is a problem. So, the cosmetic improvement
may be temporary. It is not known whether the risk of malignant
transformation is increased or not.
Table 3 Effect of Q-switch mode lasers on congenital
melanocytic nevus
|
Treatment modality
|
Patient information
|
Number of treatments and treatment intervals
|
Clinical improvement
|
Histologic changes
|
Repigmentation
|
|
1995, Goldberg & Stampien[13]
|
|
QSRL
|
n = 4 (under 6 years old)
|
2~4 times over a 1 year period
|
2: markedly inproved 2: minimally improved
|
Persistence of histologic congenital nevus
|
Minimal repigmentation (3 year follow up in one patient)
|
|
1996, Waldorf et al.[14]
|
|
QSRL
|
n = 18 (prepubertal/small to medium sized)
|
2~28 times (Average 7.7) / 2 to 4 weeks interval
|
Average 57% clearance
|
Fibrosis in the papillary dermis and upper dermis
|
Partial repigmentation (average 4.9 months after last treatment in
81% of patients)
|
|
1997, Grevelink et al.[15]
|
|
QSNdYL, QSRL
|
n = 5 (19~32 years old/medium sized))
|
Single treatment
|
Reduced pigmentation
|
Residual nevomelanocyte
|
Not reported
|
|
1999, Nelson and Kelly[16]
|
|
QSRL
|
n = 1 (2 month old/ 10cm diameter)
|
2 times, with a 3 month interval
|
Complete fading of the entire lesion
|
No evaluation
|
No repigmentation after 5 years
|
|
2001, Kono et al.[17]
|
|
NMRL + QSRL
|
n = 2 (3 year old, 24 year old/medium sized)
|
Normal mode; single pass/ QSRL; 4 or 5 passes, 4 weeks interval
|
Significant lightening (13 months after last treatment)
|
No evaluation
|
No repigmentation after 6 and 13 months
|
|
2002, Kono et al.[18]
|
Not reported
|
|
NMRL(20 J/cm2, 30 J/cm2), NMRL + QSRL
(combined)
|
n = 15 (average 16.8 years; 1~55 years old/1~5 cm in
diameter)
|
NMRL:single pass NMRL + QSRL: single NMRL+ 3 or 4 QSRL (4 weeks
interval)
|
- 1) NMRL (20 J/cm2): lightened by 42.61 ± 16.34%
Combined: 72.43 ± 15.33%
- 2) NMRL (30 J/cm2): lightened by 30.38 ± 13.95 %
Combined: 64.45 ± 13.30%
|
Marked reduction of intradermal nests of nevomelanocytes after
combination treatment
|
|
|
2003, Kang & Sangeun
|
|
QSAL (8 J/cm2 (± Liq N2, ± CO2 laser)
|
n = 53 (average 8.9 years; 3 months~45 years old/small to
giant size)
|
Average 4 times (112 times), 1~6 month interval. 16 patients
received CO2 laser treatment. (combined)
|
Average socre: 2.623 ± 1.13 (2:4160% lightening, 3:6180%
lightening)
|
mid~upper dermal fibrosis, residual nest or cells
|
44 of 53 patients had repigmentations within average 5.45 ± 3.93
months.
|
Acknowledgements
This study was supported by a grant of the Korea Health 21 R&D
Project, Ministry of Health & Welfare, Republic of Korea.
(02PJ1PG3205990021)
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|
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