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