Anzalone, Charles L

Objective: To describe a novel case of congenital profound bilateral sensorineural hearing loss in a patient with bilateral nodular internal auditory canal and labyrinthine enhancement and temporal bone dysplasia. Patients: A 76-day-old female was referred to the authors’ center for evaluation of congenital deafness. Behavioral observations and objective audiometric evaluation demonstrated bilateral profound sensorineural hearing loss and a comprehensive multidisciplinary evaluation identified compound heterozygous pathogenic variants in MYO7A , a gene associated with Usher Syndrome Type 1B or DFNB2. Computed tomography and contrast-enhanced magnetic resonance imaging studies demonstrated bilateral temporal bone anomalies with unique middle and inner ear malformations, as well as unique contrast enhancement in the membranous labyrinth, internal auditory canals, and cranial nerves, which have not been previously described with MYO7A variants. Interventions: Given the potential risk for progressive bilateral labyrinthitis ossificans, bilateral simultaneous cochlear implantation was performed at 4 months of age. Main Outcome Measures: Subsequent audiologic follow up after implantation shows significantly improved access to auditory information and increased vocalizations. At last testing, speech and language skills for both receptive and expressive language abilities were found to be commensurate with her chronological age. Conclusion: We report a novel presentation and imaging findings of congenital bilateral profound sensorineural hearing loss in a patient with nodular internal auditory canal and labyrinthine enhancement and coexisting inner ear dysplasia. Despite the multiple radiologic abnormalities, the patient has demonstrated good benefit from cochlear implantation. Future study of rare variants of congenital deafness, such as this, is critical toward defining new disease processes and determining optimal treatment.

Objective: To describe a unique case of an asymptomatic arteriovenous lesion of the internal auditory canal (IAC) and present the associated imaging findings. Methods: Retrospective case report and review of the literature. Results: A 55-year-old man presented for further evaluation of a left-sided sudden sensorineural hearing loss that occurred 8 years earlier. Careful review of outside serial magnetic resonance (MR) imaging revealed a contralateral, ill-defined right-sided IAC mass with low T2 signal and subtle peripheral enhancement on postcontrast T1-weighted sequencing. The patient had no history of right-sided otologic symptoms. Subsequent dedicated IAC MR imaging confirmed the presence of a space-occupying lesion adjacent to a complexity of vasculature. The presence of prominent flow voids, paucity of avid enhancement on previous studies, and marked signal within the lesion on time-of-flight MR angiography and MR venography was consistent with the diagnosis of a solitary arteriovenous lesion of the IAC. There was no radiological evidence of recent or remote parenchymal or subarachnoid hemorrhage or stroke. Conclusion: We report a novel case of an occult asymptomatic IAC arteriovenous lesion. Vascular anomalies confined to the IAC are rare. To date, there have been only four reports in the literature of IAC arteriovenous lesions and our case is the first to present asymptomatically. A high index of suspicion and dedicated imaging is required to identify and accurately diagnose these lesions to guide appropriate counseling and potential intervention.