Monday, April 25, 2011

Benign tumours of External Ear Canal تومورهای خوش خیم از کانال گوش خارجی




Exostosis
Osteoma
Definition
Most common bony abnormality of the EAC
True callus / hyperostosis of the bone at tympanic plate
Is a true neoplasm with fibrovascular channel

Multiple ,sessile, flat protuberance
Single , bony hard, pedunculated with stalk

Bilateral
Unilateral / slow growing
Position
Anterior and posterior canal walls. More near to TM.
At bony-cartilaginous junction , usually tympanosquamous suture
Etiology
Exact unknown
Cold-water – causes vasoconstriction of preiosteal blood vessel and reflex vasodilation leading to increase bone deposition
Swimmers ear / surfers
True neoplasm
No link to swimming
Histology
Onion like layers of compact lamella bone
No blood vessels
Cancellous bone
Fibrovascular channels
Clinical features
M:F 3:1
Small asymptomatic
Large – wax,CHL, bleeding while cleaning
Pain intermittently
Same
CT-scan
Densely solid bone
Increased heterogeneous
Treatment
If symptomatic
Post-auricular incision (due to multiple) excision
Use drill
A canalplasty can be performed to remove the offending lesions
Permeatal
Curette, drill

Can recur with re-exposure to cold water
Recurrence is unusual

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