Department of Otorhinolaryngology, Jeju National University School of Medicine, Jeju-do, Republic of KoreaSouth Korea
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The intradermal Melanocytic Nevus (MN) is usually referred to as the nevomela-nocytic nevi and is composed of nevus cells. Although intradermal nevi are common benign pigmented skin tumors, their occurrence within the External Auditory Canal (EAC) is uncom-mon. Recently the author experienced a case of huge intradermal MN which almost completely obstructed EAC orifice without accompanying conductive hearing loss in a 42-year-old female patient. It originated in the inferior wall of cartilaginous portion of left EAC. It was treated by en bloc excision without skin graft by transcanal approach. Here, we report a case of huge intradermal MN arising in the EAC with review of literatures.
Keywords: Melanocytic nevus; External auditory canal; Tumors; External auditory canal, Tumors
This article reports a case of huge intradermal Melanocytic Nevus (MN) of the Exter-
nal Auditory Canal (EAC) orifice. A nevus is a benign melanocytic neoplasm and is the most
common type of skin tumor.1 The intradermal MN is usually referred to as the nevomelanocytic
nevi and is composed of nevus cells. Although intradermal nevi are common benign pigmented
skin tumors, their occurrence within the external auditory canal is uncommon.2 There are 20 3-5 reported cases of MN in the EAC in the English-language literature thus far.3-5 Recently the
author experienced a case of huge intradermal MN which almost completely obstructed EAC
orifice without accompanying conductive hearing loss in a 42-year-old female patient. It origi-
nated in the inferior wall of cartilaginous portion of left EAC. It was treated by en bloc excision
without skin graft by transcanal approach.
A 42-year-old woman presented with 10-year history of a slow-growing mass in the
right external auditory canal (EAC) orifice associated with cosmetic discomfort. She denied
any previous medical history and reported having no hearing impairment. Physical examina-
dome-shaped, pedunculated hair-bearing mass with a mammilated surface which causes almost
the most lateral part of the EAC (Figure 1B). The otoscopic and
three fungating skin lesions with similar character on the right posterior neck area (Figure 2).
However, there were no abnormal findings on the superior portion of the trunk. Although, the
lesions were completely asymptomatic, she underwent excision
for aesthetic reason only. During the pre-operative evaluation,
dermatopathologist’s opinion helped to exclude the possibility
of malignancy such as naevoid melanoma, and confirmed that
the mass appears to be a benign intradermal nevus. High-resolu-
tion computed tomography of the temporal bone demonstrated
normal middle ear cavity and mastoid pneumatization. To ex-
clude the possibilities of vascular tumor, internal auditory canal
Magnetic Resonance Imaging (MRI) and Magnetic Resonance
Angiography (MRA) were performed. Pre-operative imaging
showed about 6×9×9 mm sized mass with high signal, oval in ap-
pearance, with heterogeneous enhancement in the right external
auditory canal orifice after gadolinium administration without
any evidence of temporal bone destruction or abnormalities in
the middle ear and mastoid (Figure 3). In the report of magnetic
resonance angiography, hemangioma was suspected because of
the progressive enhancement in the dynamic scan study and pro-
longed contrast enhancement with slow filling, but, nonetheless,
the embolization of the feeding vessel seemed not to be required
because of the small size. Under local anesthesia, complete tu-
mor excision was performed via transcanal approach. An ellipti-
cal incision was made around the base of the mass with adequate
margins under otomicroscope. The lesion was confined to the
cartilaginous EAC and completely removed. A deep margin was
taken to the level of the perichondrium. The author did not per-
form the frozen section exam during the excision because there
was no evidence of bone destruction on pre-operative images
and intraoperative finding showed well-demarcated mass cov-
ered with normal overlying skin. The skin on the base was cau-
terized to control bleeding and applied with antibiotic ointment.
And the patient asked three masses with similar features on her
right posterior neck to be removed simultaneously during the
operation. Following surgical excision, the patient experienced
an uneventful recovery. Cutaneous wound healing occurred with
complete re-epithelialization of the EAC skin defects by regular
dressing (Figure 4). Histologic analysis revealed melanocytes
arranged in round to ovoid nests or clusters located completely
within the upper dermis, the intradermal type (Figure 5A). The
nevus cells are strong positive for S-100 immunohistochemical
stain, and they are focal positive for HMB (Human melanoma
black)-45, and positive in less than 1% for Ki-67 which is cellu-
lar marker for proliferation (Figure 5B). At the 2-year follow-up
after operation, there was no sign of recurrence.
MN is the most common benign skin tumor which is
composed of nevus cell. It may be found anywhere on the skin,
but its presence in the EAC is very uncommon.2
Histologically, MN is recognized by the presence of ne-
vus cells, which, although they are melanocytes, differ from or-
dinary melanocytes by being arranged at least partially in cluster
or nests and has been classified into three subtypes depending on
the distribution of the melanocytes. A collection of nevomelano-
cytes located along the junction of the epidermis and the under-
lying dermis or remain in contact with the lower epidermis can
be classified as a junctional nevus, situated in the upper dermis
only and no longer contact the epidermis as intradermal nevus,
and a mixture which display the features of both junctional and
intradermal proliferation in both areas as a compound nevus.2 In
this case, the result was an intradermal MN. Most papillomatous
lesions and almost all dome-shaped and pedunculated lesions
represent intradermal MN.3
The nevus evolved by a process of nevus cells from the
epidermis “dropping down” into the dermis. MN in adults is pri-
marily of the intradermal type, and MN in children is primarily
of the junctional type.4
Some authors asserts that overexposure to ultraviolet
light from the sun may play a role in the skin damage that can
lead to melanoma and the formation of acquired MN.6 And the
number of moles a person has was found to have a correlation
with telomere length which may be of significance in the ageing
process.7
The common clinical manifestations of MN of the EAC
have been reported to include frequent itching, ear fullness, for-
eign body sensation, conductive hearing loss, otalgia and exces-
sive accumulation of wax with difficulty in cleaning,5,8 but most
cases were asymptomatic and were found incidentally. In this
case, although it was a completely asymptomatic, she removed
the lesion for aesthetic purpose only.
MN in EAC has the tiny risk of transformation into cu-
taneous melanoma. However, the author recommends that MN
in EAC be treated as soon as possible to prevent progression to
more advanced-staged EAC cholesteatoma. It is also believed
to be important to obtain pathological confirmation of all nevus
looking masses within the EAC by excisional biopsy when a
nevus becomes symptomatic or when all of its features cannot
be observed.1 It is known that complete scalpel excision of all
clinically atypical nevi permits the histological assessment of
the entire lesion and spares the patient the need for further surgi-
cal intervention.9
Clinical and histologic differential diagnosis include
benign lesions such as lentigo, viral wart, seborrheic keratosis,
dysplastic nevus, inflammatory polyp, encephaloceles and squa-
mous papilloma and other malignant lesions such as squamous
cell carcinoma, malignant melanoma, basal cell carcinoma.
Unlike melanomas that progress over time, MN enlarges to a
point, stabilize, and then involute.2
MN should be considered to be early diagnosed and to
be managed with early complete surgical resection for aesthetic,
functional and preventive purposes. Because MN in EAC has
the possibility of developing into an EAC cholesteatomas, espe-
cially when it is large enough to obstruct the lumen of the EAC
and the tiny risk of transformation of any single melanocytic
nevus into cutaneous melanoma. As a matter of course, the treat-
ment of choice of a symptomatic pigmented nevus in the EAC
is complete excision. The possibility of malignancy should be
excluded all the time.1 Occasionally, to avoid postsurgical scar
contracture, the auditory canal could be covered with split-thick-
ness skin graft. The prognosis of MN is substantially favorable;
however, the risk of progression to malignancy in benign mela-
nocytic lesions was recently studied in a meta-analysis,11 which
revealed a 2% incidence for melanoma, especially for congenital
nevi >40 cm located on the trunk.12
The author has received written informed consent from the pa-
tient described in this case report.