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External Auditory Canal Cholesteatoma: An
Unusual Complication of Tympanoplasty
Borligegowda Viswanatha* and Maliyappanahalli Siddappa Vijayashree
Department of Otorhinolaryngology, Bangalore Medical College &Research Institute, India
Submission: June 23, 2018; Published: July 13, 2018
*Corresponding author: BorligegowdaViswanatha, Department of Otorhinolaryngology, Bangalore Medical College & Research Institute, India,
Tel: 91-9845942832; Email: email@example.com
How to cite this article: Borligegowda V, Maliyappanahalli S V. External Auditory Canal Cholesteatoma: An UnusualComplication of Tympanoplasty
. Glob J Oto, 2018; 16(4): 555942. DOI: 10.19080/GJO.2018.16.555942
Cholesteatoma of the external auditory canal is very uncommon. Most cases occur spontaneously or after surgery (tympanoplasty, middle ear surgery, or mastoid surgery) and/or trauma in the auditory canal. Previous tympanoplasty is one of several known predisposing factors for external auditory canal cholesteatoma. In this article, the author reports 36 cases of external auditory canal cholesteatoma that occurred following a tympanoplasty. The mass was excised, and it was diagnosed on histopathology.
Schofield introduced the term external auditory canal cholesteatomain 1893 in describing a cholesteatoma that had been caused by an insect .In 1854; Toynbee was the first author to describe that cholesteatoma originates from external auditory canal as epidermal sheets. Till 1980, cholesteatoma external auditory canal and keratosis obturans were considered as different presentation of the same disease . Piepergerdes described cholesteatoma of the external auditory canal and keratosis obturans as two different pathological processes; keratosis obturans as keratin accumulation in the external auditory canal; and external auditory canal cholesteatoma as bone erosion resulting from squamous tissue on a specific spot of the external auditory canal . In this article, the author reports 36 cases of external auditory canal cholesteatoma that occurred following a tympanoplasty. The mass was excised, and it was diagnosed on histopathology.
This prospective research study was done during the period 2002 to 2017.During this period there were 36 cases of external auditory canal cholesteatoma that occurred following tympanoplasty surgery, were treated at teaching hospital. 25 patients had undergone tympanoplasty and 11 patients had undergone cortical mastoidectomy with tympanoplasty.
Presenting symptoms were otorrhea in all 36 patients; chronic
dull pain was the presenting symptom in 27 patients,3 patients
had hearing loss.25 patients had undergone tympanoplasty
and 11 patients had undergone cortical mastoidectomy with tympanoplasty.
All the patients underwent examination under microscope. In all the patients, mass was excised and external auditory canal cholesteatoma was diagnosed on histopathology(Figures 1 & 2). In 30 patients, lesion was small and mastoid air cells were not involved (Figure 3). For these patients canaloplasty was done. 5 patients had a small posterior wall defect without involving the middle ear cavity. For these patients, canal-wall up mastoidectomy and canal wall reconstruction was done. One patient had a large posterior wall defect with involvement of the middle ear cavity and in this case, canal-wall down mastoidectomy was done. Postoperative period was uneventful. All the patients were followed up for one year and there was no recurrence.
The exact etiology of external auditory canal cholesteatoma
is unclear [4,5].Cholesteatoma of the external auditory canal is
very uncommon, as it is seen in only 0.1 to 0.5% of patients who
present with an otologic disorder [2,5,6].The cholesteatoma of the
external auditory canal may arise through several mechanisms.
Occlusion or narrowing of the external auditory canal is the
basic cause .Most cases occur spontaneously or after surgery
(tympanoplasty, middle ear surgery, or mastoid surgery) and/or
trauma in the auditory canal; preexisting ear canal stenosis or
obstruction has also been described as a causative factor [8,9].
Brookes and Graham opined that when there is obstruction of
the canal, desquamation of the epithelium continues, and the
collection of impacted squamous debris may ultimately modify
the canal lining and lead to cholesteatoma formation .Several
classifications based on the Pathophysiological mechanism and
the etiologies have been reported .Farrior  classified
cholesteatoma of the external auditory canal into four groups:
a) Complicating congenital aural artesia and stenosis of
the external auditory canal;
b) Following tympanoplasty, middle ear surgery or
trauma to the skin of the external auditory canal;
c) Related to keratosis obturans;
d) Associated with focal osteitis, sequestrisation of bone
and inflammation of the skin of theexternal auditory canal.
In 1992, Holt  speculated upon the causes of cholesteatoma
of the external auditory canal and listed five groups in which
this entity may be seen:
a) Postoperative patients.
b) Post-traumatic patients.
c) Patients with ear canal stenosis (often congenital).
d) Patients with ear canal obstruction due to tumor or
e) A large group of patients in which cause is unknown.
Affected patients typically present with otorrhea and a
chronic, dull pain secondary to the local invasion of squamous
tissue into the bony external auditory canal. Hearing loss is not
common unless the cholesteatoma invades the middle ear or
attic. Rarely cholesteatoma debris form in the ear canal to cause
conductive hearing loss [3,7].The diagnosis is based on the
history, clinical examination, and audiometric findings. Although
external auditory canal cholesteatoma has characteristic imaging
features (its defining feature on computed tomography is a softtissue
attenuating mass in the canal with erosion of the adjacent
bone), imaging is usually not performed for diagnosis[4,7].It
is required when there is extension beyond external auditory
canal .CT scan is important to evaluate for disease extension
into the middle ear cavity and for the integrity of the facial
nerve canal, tegmen tympani, and mastoid air cells, because
these features may change the surgical management of external
auditory canal cholesteatoma .
The reported complications of an external auditory
canal cholesteatoma include facial palsy, ossicle erosion, and
labyrinthine fistula These complications can occur as a
result of an extensive cholesteatoma extending to the mastoid
or the middle ear  Extensive invasion in to the mastoid cavity
has a propensity to involve the vertical segment of the facial
nerve[2,7,12,13]. Those external auditory canal cholesteatomas
that occur as a complication of surgery or trauma are more
likely than other forms to violate the middle ear cavity, and
they commonly require surgical treatment . The choice of
procedure is determined by the extent of the cholesteatoma.
Canaloplasty is sufficient for small lesions that do not involve
the mastoid air cell. For patients with a small posterior wall
defect that does not involve the middle ear cavity, canal-wall up
mastoidectomy and canal wall reconstruction should be done. For
patients who have a large posterior wall defect and involvement
of the middle ear cavity, canal-wall down mastoidectomy is