cochlear aplasia

Cochlear aplasia, or complete absence of the cochlea is a rare anomaly which accounts for only 3% of cochlear malformations.

Radiographic features

• complete absence of the cochlea. Dense otic bone is seen at the anatomical site of the cochlea
• cochlear nerve canal and cochlear nerve are absent
• cochlear promontory is hypoplastic and flattened
• the vestibule and semicircular canals are often malformed, stunted, dilated but may be normal
• vestibular aqueduct is normal
• internal auditory canal usually hypoplastic
• facial nerve canal usually anomalous showing obtuse angle anterior genu
• middle ear is usually normal sized with normal ossicles
• oval window usually normal but may be atretic 

Differential diagnosis

• labyrinthitis ossificans
  • normal-sized bone is seen anterior to the IAC
  • the bulge of the cochlear promontory produced by the basal turn of the cochlea is present
• common cavity deformity
• cystic cochleovestibular anomaly
• labyrinthine aplasia

See also

• cochlear anomalies (classification)

Siehe auch:

• Cochlea
• Mondini-Dysplasie
• Anomalien der Cochlea