Mondini Malformation and Vestibular Aqueduct Syndrome
Findings:
Axial CT of the right temporal bone shows a globular
appearing cochlea and a markedly dilated vestibular aqueduct.
Discussion:
Mondini malformation is the term often used to describe
any inner ear dysplasia, but more precisely it refers to lack of normal
2.5 turns of the cochlea. In this malformation, the cochlea has a cystic
appearance with variable development of the basal turn and absent normal
development of the middle and apical turns.Vestibular aqueduct syndrome
is characterized by a enlargement of the vestibular aqueduct with or without
enlargement of the vestibule. VAS is the most commonly missed cause of
congenital deafness. Clinically, these patients hear normally during the
first few years of life, with progressive SNHL developing as late as the
teenage years. VAS may be unilateral or bilateral. Michel aplasia represents
the most severe form of otic capsule dysplasia, in which there is complete
cochlear agenesis.
reference: Harnsberger, H. Handbook of Head and Neck Imaging. 1995: Mosby Year Book. p. 451.