Case #3

CT

• Symmetric developmental anomalies of the bilateral temporal bones:
  • External ears:
    • Abnormal axis of the temporal bone, which is downward sloping laterally
    • Elongated, stenotic appearance of the external auditory canals, which measure a minimum of 1 mm in diameter on the right and 2.5 mm on the left near the junction of the cartilaginous and bony segments
    • The tympanic membrane is not clearly visualized on either side. Tympanostomy tube on the left
  • Middle ears/mastoids:
    • Partial opacification bilaterally
    • Underpneumatized, opacified bilateral mastoid air cells
    • Dysplastic appearance of the malleus and incus with mild widening and abnormal anteroposterior orientation of the malleoincudal joint. Possible fusion of the incus to the medial wall of the epitympanum
    • The stapes is not clearly visualized on the right and is severely dysplastic appearing on the left
    • The oval window is atretic on the right and stenotic on the left
    • The round windows are hypoplastic/stenotic bilaterally (left, right)
    • Elongated bilateral labyrinthine segments of the facial nerves with poor delineation of the tympanic and mastoid segments
  • Inner ears:
    • Narrowed appearance of the bilateral internal auditory canals
    • Bilateral cochlear hypoplasia with poor development of the apical turns
    • Severely stenotic bilateral cochlear apertures (left, right)
    • Hypoplastic vestibule bilaterally with underformed and dysplastic appearing elements of bilateral semicircular canals
  • Additional findings:
    • Hypoplastic bilateral jugular foramina with multiple prominent emissary veins
    • Hypoplasia of the central skull base
    • Basilar invagination with protrusion of the odontoid process through the foramen magnum
    • Cleft palate with bony defects both anteriorly and posteriorly
    • Incomplete vomer with deficiency of the posterior bony nasal septum inferiorly
    • No discernible parotid glands

MRI

• Only two nerves are identified in the internal auditory canal bilaterally. The nerves are posteriorly positioned bilaterally and are favored to represent the superior and inferior vestibular nerves with no cochlear or facial nerve identified