Clinical and Radiological Findings in Children with Anomalous Pontine Cranial Nerves.

ABSTRACT

We retrospectively reviewed the clinical and radiologic findings in 17 children with an aberrant cisternal CN7 and found that these patients had additional anomalies involving other pontine cranial nerves. The hallmark imaging feature identified in all patients was aberrant cisternal segment of an enlarged appearing CN7. The abnormal nerve coursed anteriorly towards the Gasserian ganglion where it fanned out towards the internal auditory canal, Meckel's cave or both. This finding was accompanied by a small cisternal CN5 which often had a lateral bowed appearance. CN5 and CN7 were abnormally close to each other. Meckel's cave appeared widened posteriorly and often was close to or merged with the internal auditory canal. Other abnormalities in the pontine cranial nerves included CN8 deficiency in the majority of children and variable CN6 deficiency. This constellation of findings was most often discovered in children having MR evaluation for sensorineural hearing loss and the majority of patients had preserved facial nerve function. In patients with available genetic testing, no pathogenic variants were observed. Interestingly, in 13 children with available birth history, 9 were notable for maternal or gestational diabetes (69%), suggesting a possible early intrauterine insult to the developing nerves.ABBREVIATIONS CN= cranial nerve; OAVS= Oculo-Auriculo-Vertebral Spectrum; IAC= Internal Auditory Canal; PTCD= Pontine Tegmental Cap Dysplasia; EMR= Electronic Medical Record; SNHL= sensorineural hearing loss.