External Auditory Canal Atresia

Also known as congenital aural dysplasia, or microtia, this condition is characterised by bony atresia of the external auditory canal (EAC) and a dysplastic auricle. Findings in the middle ear are variable and the inner ear and internal auditory canal are typically normal.
The incidence is 1 in 10,000 births and is thought to be due to an in-utero insult, with epithelial cells of the first branchial groove failing to split and canalize. The condition may be associated with inherited syndromes such as Crouzon, Goldenhar or Pierre-Robin syndromes where the EAC atresia is frequently bilateral.
A normal morphology and location of the stapes is important for surgical reconstruction of ossicular function. EAC atresia may be complicated by congenital cholesteatoma formation behind the atresia plate.
A number or key points should be looked for and specifically mentioned in reports as it impacts on surgical reconstruction: the ossicles especially stapes; inner ear structures; course of carotid - if abnormal can be hazardous during surgery; course of jugular - if abnormal can be hazardous during surgery; course of facial nerve - often abnormally anterior and can be damaged during reconstruction.
For a coronal image of this same case please visit Radiopaedia.org here.
Reference:
1. Harnsberger, et al. Pocket Radiologist: Head and Neck. Top 100 Diagnoses. Amirsys 2002.
Credit: Dr Frank Gaillard
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