Internal auditory canal enlargement (Giant IAC) and defective fundus in a child with congenital neurosensorial hearing loss

SummaryA 14-month-old boy with congenital neurosensorial hearing loss and inner ear abnormality is presented. ABR demonstrated 80 dB hearing threshold on both sides. Computerized tomography demonstrated normal semicircular canals, normal vestibule, and normal vestibular aqueduct. At least two turns of cochlea was evident with well-formed basal turn. However, there was a bilateral bulbous enlargement of the internal auditory canal with bony dehiscence at the fundus. T2-weighed MRI demonstrated well-developed eighth nerve on both sides. This rare abnormality was discussed in the light of classifications of cochleovestibular anomalies.