Bizakis, John G

Drivas, Emmanouil I

Feritsian, Antzela

Ioannidis, Dimitris G

Papadakis, Chariton E

Skoulakis, Charalampos E

English

PubMed

Dimitris G Ioannidis

Emmanouil I Drivas

Chariton E Papadakis

Antzela Feritsian

John G Bizakis

Charalampos E Skoulakis

Springer - Publisher Connector

Hidrocystoma of the external auditory canal: a case report

BioMed CentralCases Journal
ssOpen AcceCase Report
Hidrocystoma of the external auditory canal: a case report
Dimitris G Ioannidis*1, Emmanouil I Drivas2, Chariton E Papadakis2, 
Antzela Feritsian3, John G Bizakis2 and Charalampos E Skoulakis1
Address: 1Department of Otorhinolaryngology, General Hospital of Volos, Magnesia, 38222, Greece, 2Department of Otorhinolaryngology, 
University of Crete School of Medicine, Heraklion, Crete, Greece and 3Department of Histopathology, General Hospital of Volos, Magnesia, 
38222, Greece
Email: Dimitris G Ioannidis* - dimitrisioann@gmail.com; Emmanouil I Drivas - em_drivas@yahoo.gr; 
Chariton E Papadakis - papch@otenet.gr; Antzela Feritsian - AntzelaFe@hotmail.COM; John G Bizakis - Johnbizakis@hotmail.com; 
Charalampos E Skoulakis - skulakis@hotmail.com
* Corresponding author    
Abstract
Background: Apocrine hydrocystomas arising in the external auditory canal are very rare. In this
report a clinical case of apocrine hydrocystoma located in the cartilaginous part of the external
auditory canal is presented.
Case presentation: A 64-year-old Caucasian female patient presented with a solitary nodule,
located in the outer part of the external ear canal after repeated episodes of external otitis. For
diagnostic purposes, computerized tomography was used. The patient underwent an excisional
biopsy of the mass via an intra-aural incision and the surgical specimen was sent for histopathologic
examination.
Conclusion: An apocrine hidrocystoma inside the auricular canal is uncommon. It can cause
recurrent external otitis and conductive hearing loss and should be treated with wide local excision
and reconstruction of the external auditory canal for diagnostic and therapeutic purposes.
Background
The lateral one-third of the external auditory canal is car-
tilaginous and covered with a thin epithelium, firmly
bound to the perichondrium and with scant subcutane-
ous tissue [1]. Hair follicles formed by invagination of epi-
dermis are numerous in the outer one-third of the
cartilaginous canal but are less noumerous in the inner
two-thirds. Sebaceous glands are plentiful and open into
the follicles of fine vellus hair. Eccrine sweat glands are
not present in the auditory canal, but it is abundantly sup-
plied with modified (ceruminous) glands. The number of
these glands varies considerably, in individuals and in
many races, with the primary concentration in the carti-
laginous part of the canal, but with some sparse distribu-
tion in the osseous portion. These glands secrete at a very
low, constant rate. Histologicaly, the apocrine glands lie
deep in the dermis adjacent to the cartilage. They are com-
prised of an inner columnar, eosinophilic epithelium
which is surrounded by an outer layer of myoepithelial
cells. The secretion of the glands is strongly PAS positive
and is at times stored in the gland lumina in sufficient
quantities to cause glandular dilatation. Whereas the func-
tion of eccrine sweat glands is to help regulate the body
heat and fluid, the apocrine sweat glands have this role to
a lesser degree and indeed, in the ear canal, have a more
protective function. Cerumen itself derives from the seba-
Published: 22 January 2009
Cases Journal 2009, 2:79 doi:10.1186/1757-1626-2-79
Received: 15 December 2008
Accepted: 22 January 2009
This article is available from: http://www.casesjournal.com/content/2/1/79
© 2009 Ioannidis et al; licensee BioMed Central Ltd. 
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), 
which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.Page 1 of 4
(page number not for citation purposes)
Cases Journal 2009, 2:79 http://www.casesjournal.com/content/2/1/79ceous and apocrine glands of the ear canal. The acidity of
these secretion keeps the pH of the auditory canal
between 5,6 – 5,8 near the concha and to 7,3 – 7,5 at a dis-
tance of 5–10 mm within the canal. This acidity helps
combat many organisms implicated in external canal
infections, most of which grow best in an alkaline
medium with a pH between 7,2 – 7,6. In addition, these
glandular secretions provide a protective water proof coat-
ing for the skin. These functions, along with the natural
lateral migration of the meatal skin at the rate of 1,5 mm
per month, play an important part in the antimicrobial
defense mechanism of the ear canal [1].
Hidrocystomas are rare, benign skin adnexal neoplasms,
sometimes presenting as cystic lesions [2]. According to
the histologic characteristics and presumed histogenic
derivation, hidrocystomas have been categorized into two
types (apocrine and eccrine). Eccrine hidrocystomas
present as small, tense, thin-walled cysts, ranging from 1–
6 mm in diameter, and can occur as single or multiple
lesions. They are found predominantly in adult females,
are located mostly on the periorbital and malar regions,
and are prevalent in adults between 30 and 70 years of
age. Apocrine hidrocystomas arise from the proliferation
of apocrine glands and are usually solitary, with a diame-
ter of 3–15 mm. Apocrine lesions are also found mostly
on the head and neck and along the eyelid margin near
the inner canthus. The general distribution of lesions
tends to occur in similar locations on the body for both
types of hidrocystomas [[2,3], and [4]].
We describe a patient with an apocrine hidrocystoma in
the auricular canal. In the English literature, very few cases
of apocrine hidrocystomas originating in the external
auditory canal have been reported. A single, related case
has been identified in the PUBMED database [3] of an
apocrine hidrocystoma involving the pinna and another
one is reported in the Iranian Red Crescent Medical Jour-
nal [5]. The clinical and histological features, the differen-
tial diagnosis, and the treatment of apocrine
hydrocystoma are discussed.
Case presentation
A 64-year-old Caucasian female presented to our depart-
ment with slowly developing left side hearing loss and
recurrent external otitis. Physical examination revealed a
tender solitary, skin-colored, dome-shaped nodule arising
from the inferior and posterior wall of the left external
auditory canal that narrowed the external auditory meatus
and canal (figure 1). Pure tone audiometry revealed a
mild conductive hearing loss on the left side. Computer-
ized tomography (CT) scan of the temporal bone (figure
2) demonstrated a well-circumscribed, soft tissue narrow-
ing most of the external auditory canal. The mass arised
from the inferior and posterior canal wall at the cartilagi-
Photographic image of the apocrine hidrocystoma inside the auricular canal with the use of a rigid 0° 6-cm endoscopeFigure 1
Photographic image of the apocrine hidrocystoma 
inside the auricular canal with the use of a rigid 0° 6-
cm endoscope.
Axial, soft tissue window CT scan demonstrating a polypoid soft tissue mass located at the posterior canal wall extending from the entrance to the bone-cartilage limit of the audit rycan 7.9 mm i diamet rFigure 2
Axial, soft tissue window CT scan demonstrating a 
polypoid soft tissue mass located at the posterior 
canal wall extending from the entrance to the bone-
cartilage limit of the auditory canal, 7.9 mm in diam-
eter.Page 2 of 4
(page number not for citation purposes)
Cases Journal 2009, 2:79 http://www.casesjournal.com/content/2/1/79nous portion of the external auditory canal, with no bone
erosion and no middle ear or mastoid involment.
The patient underwent, under local anesthesia, an exci-
sional biopsy of the mass via an intra-aural incision. The
mass was removed while preserving the osteocartilagi-
nous canal wall and the integrity of the underlying tym-
panic membrane. The external auditory canal was packed
with a Merocel wick to support the skin and to prevent
canal stenosis for two weeks. The patient made an une-
ventful recovery and there was no recurrence during two
years of follow-up.
Histopathologic examination of paraffin sections of the
specimen, stained with haematoxylin-eosin (figure 3),
revealed the presence of a cyst in the dermis lined by a
one-or two-layered cuboidal or flattened epithelium rest-
ing on a layer with spindle myoepithelial cells. In close
vicinity to the cyst were groups of apocrine glands, partly
dilated, showing the typical eosinophilic epithelium with
evidence of decapitation secretion, the pathognomonic
finding of apocrine differentiation [[6,7], and [8]]. The
deepest group of glands was situated close to mature car-
tilage. Immunohistochemistry revealed epithelial mem-
brane antigen (EMA) expression in all the cells of the cyst
wall, while carcinoembryonic antigen (CEA) focally-deco-
rated the luminal cells. Smooth muscle actin (SMA) was
present in the basal layer. Human milk fat globulin 1
(HMFG) and gross cystic disease fluid protein 15
(GCDFP-15), which is regarded as a marker of apocrine
epithelium [7,8], were weakly positive in some cells of the
cyst wall, showing decapitation secretion, while being
strongly positive in the cells of all of the above described
glandular groups. These light microscope findings were
considered diagnostic of the apocrine nature of the lesion
in question.
Discussion
Skin adnexal neoplasms exhibit morphological differenti-
ation towards one or more types of adnexal structures
found in normal skin (pilosebaceous units, eccrine
glands, and apocrine glands) and comprise a wide spec-
trum of benign and malignant tumours, including cylin-
dromas, spiradenomas, trichoepitheliomas,
trichoblastomas, sebaceous adenomas, sebaceomas, seba-
ceous carcinomas, syringomas, microcystic adnexal carci-
noma, papillary eccrine adenomas, tubular apocrine
adenomas, hidradenomas, poromas, digital papillary ade-
nomas/adenocarcinomas, adenoid cystic carcinomas,
syringoid/eccrine carcinomas, apocrine (axillary) carcino-
mas, eccrine and apocrine hidrocystomas, and admixtures
of these entities [6]. Most adnexal neoplasms are uncom-
monly encountered in routine practice, and pathologists
can recognise a limited number of frequently encountered
tumours.
McCalmont [6] offered a logical and systematic approach
to the classification of adnexal neoplasms by dividing
these lesions into two main diagnostic categories: 1)
eccrine and 2) folliculosebaceous-apocrine. The corner-
stone of this classification scheme derives from the
embryology of epidermal development.
Most adnexal tumors are benign, but many have definite
recurrence and malignant potential if incompletely
excised. Therefore, the presence of any atypical or malig-
nant features, such as asymmetric growth, jagged/infiltra-
tive borders, irregular arrangement of neoplastic cells,
cytonuclear atypia, increased mitotic activity, tumour
necrosis, and superficial ulcerations in a given case should
be accessed, and complete excision for lesions that are
only partially sampled is recommended to facilitate com-
plete evaluation and to prevent future recurrence and rare
malignant transformation [6,7].
Both benign and malignant tumors grow along the path
of least resistance, extending laterally out the meatus or
medially through the tympanic membrane and into the
middle ear [9]. Invasive malignant tumors also extend
radially through auricular cartilage and the fissures of San-
torini into the parotid gland or into surrounding periau-
ricular tissue. Medial extension with erosion of tympanic
membrane or temporal bone is also indicative of malig-
nancy. Diagnosis is made on the basis of microscopic
Histopathologic section of the surgical specimen demonstrat-ing a cyst in the d rmis lined by a one-or two-layered cuboi-dal or flattened epithelium resting on a layer with spindle myoe ithelial cellsFi u e 3
Histopathologic section of the surgical specimen 
demonstrating a cyst in the dermis lined by a one-or 
two-layered cuboidal or flattened epithelium resting 
on a layer with spindle myoepithelial cells. In close 
vicinity to the cyst are groups of apocrine glands, partly 
dilated, showing the typical eosinophilic epithelium with evi-
dence of decapitation secretion (H&E, original magnification 
10×).Page 3 of 4
(page number not for citation purposes)
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examination of biopsy specimens. To distinguish between
benign and malignant tumors, biopsy specimens should
be large enough to identify deep tissue invasion. HRCT of
the temporal bone and MRI of soft tissue around the lat-
eral skull base can be helpful in this respect also [9,10].
Benign tumors are treated with wide local excision and
reconstruction of the external auditory canal. Because of
high recurrence rates, especially in cases of adenoid cystic
carcinoma, treatment of malignant lesions should be
aggressive. Lateral temporal bone resection with parotid-
ectomy and postoperative radiation therapy is appropri-
ate for early lesions. Larger malignant tumors require a
more extensive temporal bone resection and cervical
lymph node dissection in addition to parotidectomy and
postoperative radiation therapy [9,10].
Conclusion
We have described an unusual appearance of an apocrine
hidrocystoma inside the auditory canal of a female patient
that caused occlusion, conductive hearing loss and sec-
ondary otitis externa. Although diagnosis relies on biopsy
with histologic examination, diagnostic imaging by CT-
scan is necessary for defining the characteristics, extension
of the lesion and for planning the therapeutic approach.
Localized excisional biopsy is the treatment of choice for
external auditory canal apocrine hydrocystomas via intra
aural or rertoauricular approach while preserving the adja-
cent structures.
Abbreviations
ENT: ear, nose, throat; CT: computerized tomography;
FNA: fine needle aspiration; PAS: periodic acid Schiff;
CEA: carcinoembryonic antigen; EMA: epithelial mem-
brane antigen; GCDFP-15: gross cystic disease fluid pro-
tein 15; HMWK: high molecular weight keratin; LMWK:
low-molecular weight cytokeratin; SMA: smooth muscle
actin
Consent
Written informed consent was obtained from the patient
for publication of this case report and accompanying
images. A copy of the written consent is available for
review by the Editor-in-Chief of this journal.
Competing interests
The authors declare that they have no competing interests.
Authors' contributions
CES was responsible for diagnosing and performing sur-
gery on the patient. DGI drafted and prepared the manu-
script. CEP was responsible for review of the literature.
EID reviewed the patient's medical record in order to col-
lect all the available information. JGB was involved in
revising the article for intellectual details. AF performed
the histologic examination of the surgical specimen. All
authors read and approved the final manuscript.
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A Call for Logic of Adnexal Neoplasms in the Classification.

Apocrine hidrocystadenoma of the ear. Otolaryngol Head Neck Surg

Apocrine hidrocystoma: a case report and analysis of 167 Japanese cases.

Apocrine hidrocystoma: report of a case.

Azarpira N: Apocrine hidrocystoma in the external auditory canal. Iranian Red Cresc Med J

Cassarino DS: Cutaneous Adnexal Neoplasms With Eccrine or Apocrine Differentiation: Diagnostic Distinction, and Does It Really Matter? Pathol Case Rev

EM: Adenoid Cystic Carcinoma of the External Auditory Canal. Laryngoscope

Khachemoune A: Hidrocystomas – a brief review. MedGenMed

Neoplasms of the Ear and Lateral Skull Base.

Tumors arising from the glandular structures of the external auditory canal. Laryngoscope

http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=2637255

Hidrocystoma of the external auditory canal: a case report

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