Dr Patrick Treacy shares some of his most challenging cases. This month he talks about a giant congenital melanocytic nevus. The congenital melanocytic nevus is a type of melanocytic nevus (or mole) found in infants at birth. This type of birthmark occurs in an estimated 1% of infants worldwide; it is located in the area of the head and neck 15% of the time.

1. 43
CASE FILES
Aesthetic Medicine • October 2014
S K I N
www.aestheticmed.co.uk
Dr Patrick Treacy shares some of his most
challenging cases. This month he talks about
a giant congenital melanocytic nevus
Dr Treacy’s
CASEBOOK
DR PATRICK TREACY
is chairman of the Irish
Association of Cosmetic
Doctors and Irish regional
representative of the British
College of Aesthetic Medicine
(BCAM). He is European medical
advisor to Network Lipolysis
and Consulting Rooms and
holds higher qualifications in
dermatology, laser technology
and skin resurfacing. In 2012
and 2013 he won awards for
‘Best Innovative Techniques’
for his contributions to
facial aesthetics and hair
transplants. Dr Treacy also
sits on the editorial boards
of three international
journals and features regularly
on international television and
radio programmes. He was a
faculty member at IMCAS
Paris 2013, AMWC Monaco
2013, EAMWC Moscow 2013
and a keynote speaker for
the American Academy of
Anti-Ageing Medicine in
Mexico City this year.
>>
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A
40 year old Indian male presented with a large congenital nevus covering
most of his lower body. The naevus measured 35 cm x 20 cm with a flat
mammilated surface, well-demarcated borders and some degree of
hypertrichosis. Dermoscopic examination showed coarse pigment in
the darker centre of the naevus and deeper pigmentation around its
periphery. The patient said that over time, it had become darker with an increase in
hair growth, and it had acquired a more irregular surface.
It had a major psychological effect on the patient
and he felt it had prevented him finding a mate.
The patient was aware of the possibility of
developing melanoma, within the lesion.
Although the value of the incidence rate of
malignancies in GCMN may still be a matter
of dispute, it is estimated that for these
individualsthelifetimeriskfordeveloping
melanoma is between five and 10%.
Another doctor in India had commenced
the treatment but referred him to my
clinic as we had a more powerful CO2 laser.
When melanoma
arises in GCMN, the
prognosis is poor. One of
the reasons is the fact that
cutaneous melanoma associated
with GCMN typically grows
in the dermis and this makes
it more difficult to detect
in clinical exams
HISTOLOGY
Light microscopy showed well-
formed naevus cell nests with coarse
melanin granules in the papillary
dermis, and surrounding fibrosis.
The histopatholgy report stated
“symmetrical broad proliferation of
melanocytes in papillary and reticular
dermis with maturation, splaying
between collagen bundles, permeation
of muscles of hair erection, blood
vessels, adnexa”.

2. 44 Aesthetic Medicine • October 2014
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CASE FILES SPONSORED BY
DISCUSSION
Congenital melanocytic nevus (CGN) is
primarily a clinical diagnosis. It is usually
defined as a melanocytic lesion present at
birth that will reach a diameter ≥ 20 cm
in adulthood. Its incidence is estimated
in <1:20,000 newborns.1, 2 Despite
its rarity, this lesion is important
because it may associate with severe
complications such as malignant
melanoma, affect the central nervous
system and have major psychosocial
impact on the patient and his family due to
its unsightly appearance.3,4
However, congenital nevi are histologically
distinguished from acquired nevi mainly by
their larger size, the spread of the nevus cells
to the deep layers of the skin and by their more
varied architecture and morphology. Although giant congenital
melanocytic nevus is recognized as a risk factor, the risk of
malignant melanoma in congenital melanocytic naevi (CMN) is a
matter of ongoing debate. In one study, fourteen articles were
chosen for further analysis. The studies varied significantly
with respect to study design (source of cases; retrospective
vs. prospective analysis), age of patients, follow-up time, and
nevus characteristics. The overall risk of melanoma of 0.7% in
all 14 studies5. Although satisfying to this author, this was lower
than many other studies that show the estimated lifetime risk
of developing melanoma varies from 5 to 10%6. On account of
these uncertainties and the size of the lesions, the management
of giant congenital melanocytic nevus needs individualisation.7
The issue of deciding which is the best therapeutic approach
in these cases also causes distress to the medical team, due to
the controversies surrounding the treatment of these lesions
– which stems largely from the uncertainties about the risks of
complications8.Treatmentmayincludesurgicalandnon-surgical
procedures, psychological intervention and/or clinical follow-
up, with special attention to changes in color, texture or on the
surface of the lesion. The only absolute indication for surgery
in giant congenital melanocytic nevus is the development of a
malignant neoplasm on the lesion9. GCMN diagnosis is mainly
clinical. From the histological standpoint, however, CMN is
generally differentiated from acquired nevus mainly by its larger
size,thedisseminationofnevuscellsintothedeeperlayersofthe
skin (including subcutaneous tissues) and its varied architecture
and morphology.10
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When melanoma arises in GCMN,
the prognosis is poor. One of the
reasonsisthefactthatcutaneous
melanoma associated with
GCMN typically grows in the
dermis and this makes it
more difficult to detect in
clinical exams. More than
half of the patients will die
within three years and the
median age at death is 4.5
years.11 Prophylactic surgical
excision is justified based on
the assumption that melanoma
may arise on the nevic lesion.
However, 50% of melanomas found
in patients with GCMN occur elsewhere
and the removal of the nevus does not guarantee
protection against malignancy.12 It is logical
to assume the reduction of melanocytic cells
reduces the incidence of malignancy. However,
the partial removal of GCMN by procedures such
as fractionalised CO2 laser treatment has only
cosmetic purposes, since only the most superficial
cells of the lesion are removed.13
CONCLUSION
The use of CO2 laser in the treatment of GCMN
remainscontroversialasthereissomeconcernthat
nevus cells exposed to doses of energy may have a
higher probability of malignant transformation.14
There is also a suspicion whether laser surgery
that partially removes congenital pigmented
lesions could impair or facilitate the detection
of abnormalities suggestive of melanoma on the
nevus.15 There is also the counter-argument that
reducing the overall number of melanocytic cells
can only reduce the risk of these turning malignant.
However, these effects must be balanced
against the psychological impact that the lesion
has on the patient as there is no doubt that CO2
laser can dramatically improve the gross aesthetic
appearance of these lesions. AM
The use of CO2 laser in
the treatment of GCMN
remains controversial as there
is some concern that nevus cells
exposed to doses of energy may
have a higher probability of
malignant transformation