External auditory canal cholesteatoma
Updates to Synonym Attributes
Updates to Article Attributes
A cholesteatomaCholesteatomas may may sometimes occur lateral to the tympanic membrane, in which case it is called a cholesteatoma of the external earauditory canal (EECC cholesteatoma (EACC).
Epidemiology
The EECexternal acoustic canal (EAC) is a rare location for a cholesteatoma with an estimated incidence around 1.2 per 1,000 new otological patients. The overall incidence rate in one large study was 0.30 per year per 100,000 inhabitants 1. For comparison, the annual incidence of middle ear cholesteatoma is around 9.2 per 100.000,000.
Pathology
EECC hasEACC has been first reported by Toynbee in 1850. A distinction from keratosis obliterans has been introduced only in the last few decades. Both mainly consist of epithelial debris in the EECEAC. The most useful findings confirming an EECCEACC are focal osteonecrosis with or without sequestration and lack of epithelial covering of the bony surface 2. The treatment strategies differ with both conditions 3.
Classification
- primary or spontaneous EECC: idiopathic form, the pathogenetic events are unclear (rare)
-
secondary
EECCEEC: postoperative, postinflammatory, posttraumatic, radiation-induced - EECC with congenital atresia of the external auditory canal
Radiographic features
Plain film
Schüller, Stenvers, and Mayer views of the petrous bone have been largely replaced by CT.
CT
High-resolution bone window CT is the method of choice to localise the lesion and to demonstrate bony erosions.
MRI
Can'tCannot show early involvement of compact bone. Its role in EECCEACC is unknown.
Treatment and prognosis
Small lesions can be treated endoscopically under local anaesthesia, whereas larger lesions need surgery to remove the cholesteatoma and affected bone areas. Grafting of defects may be necessary. Prognosis depends on the extent at the time of diagnosis.
Differential diagnosis
General imaging differential considerations include:
-<p>A <a href="/articles/cholesteatoma">cholesteatoma</a> may sometimes occur lateral to the tympanic membrane, in which case it is called a <strong>cholesteatoma of the external ear canal (EECC)</strong>.</p><h4>Epidemiology</h4><p>The EEC is a rare location for a cholesteatoma with an estimated incidence around 1.2 per 1,000 new otological patients. The overall incidence rate in one large study was 0.30 per year per 100,000 inhabitants <sup>1</sup>. For comparison, the annual incidence of middle ear cholesteatoma is around 9.2 per 100.000.</p><h4>Pathology</h4><p>EECC has been first reported by Toynbee in 1850. A distinction from keratosis obliterans has been introduced only in the last few decades. Both mainly consist of epithelial debris in the EEC. The most useful findings confirming an EECC are focal osteonecrosis with or without sequestration and lack of epithelial covering of the bony surface <sup>2</sup>. The treatment strategies differ with both conditions <sup>3</sup>.</p><h5>Classification</h5><ul>- +<p><a href="/articles/cholesteatoma">Cholesteatomas</a> may sometimes occur lateral to the <a href="/articles/tympanic-membrane">tympanic membrane</a>, in which case it is called a <strong>external auditory canal cholesteatoma </strong>(EACC). </p><h4>Epidemiology</h4><p>The external acoustic canal (EAC) is a rare location for a cholesteatoma with an estimated incidence around 1.2 per 1,000 new otological patients. The overall incidence rate in one large study was 0.30 per year per 100,000 inhabitants <sup>1</sup>. For comparison, the annual incidence of middle ear cholesteatoma is around 9.2 per 100,000.</p><h4>Pathology</h4><p>EACC has been first reported by Toynbee in 1850. A distinction from keratosis obliterans has been introduced only in the last few decades. Both mainly consist of epithelial debris in the EAC. The most useful findings confirming an EACC are focal osteonecrosis with or without sequestration and lack of epithelial covering of the bony surface <sup>2</sup>. The treatment strategies differ with both conditions <sup>3</sup>.</p><h5>Classification</h5><ul>
-<strong>primary or spontaneous EECC:</strong> idiopathic form, the pathogenetic events are unclear</li>- +<strong>primary or spontaneous EECC:</strong> idiopathic form, the pathogenetic events are unclear (rare)</li>
-<strong>secondary EECC: </strong>postoperative, postinflammatory, posttraumatic, radiation-induced</li>- +<strong>secondary EEC: </strong>postoperative, postinflammatory, posttraumatic, radiation-induced</li>
-</ul><h4>Radiographic features</h4><h5>Plain film</h5><p>Schüller, Stenvers, Mayer views of the petrous bone have been largely replaced by CT.</p><h5>CT</h5><p>High-resolution bone window CT is the method of choice to localise the lesion and to demonstrate bony erosions.</p><h5>MRI</h5><p>Can't show early involvement of compact bone. Its role in EECC is unknown.</p><h4>Treatment and prognosis</h4><p>Small lesions can be treated endoscopically under local anaesthesia, whereas larger lesions need surgery to remove the cholesteatoma and affected bone areas. Grafting of defects may be necessary. Prognosis depends on the extent at the time of diagnosis.</p><h4>Differential diagnosis</h4><p>General imaging differential considerations include:</p><ul><li><a href="/articles/keratosis-obliterans">keratosis obturans</a></li></ul>- +</ul><h4>Radiographic features</h4><h5>Plain film</h5><p>Schüller, <a title="Stenvers view" href="/articles/stenvers-view">Stenvers</a>, and Mayer views of the petrous bone have been largely replaced by CT.</p><h5>CT</h5><p>High-resolution bone window CT is the method of choice to localise the lesion and to demonstrate bony erosions.</p><h5>MRI</h5><p>Cannot show early involvement of compact bone. Its role in EACC is unknown.</p><h4>Treatment and prognosis</h4><p>Small lesions can be treated endoscopically under local anaesthesia, whereas larger lesions need surgery to remove the cholesteatoma and affected bone areas. Grafting of defects may be necessary. Prognosis depends on the extent at the time of diagnosis.</p><h4>Differential diagnosis</h4><p>General imaging differential considerations include</p><ul>
- +<li><a href="/articles/keratosis-obliterans">keratosis obturans</a></li>
- +<li><a title="Necrotising otitis externa" href="/articles/necrotising-otitis-externa-1">necrotising otitis externa</a></li>
- +</ul>
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