Case report: "auditory neuropathy" in a newborn caused by a cerebellopontine angle arachnoid cyst.

We present a 6-week-old girl, referred because of failed newborn hearing screening in the right ear. Click-evoked oto-acoustic emissions were present in both ears, auditory brainstem responses (ABR) were present in the left but totally absent in the right ear. A magnetic resonance imaging (MRI) study revealed a large arachnoid cyst in the right cerebellopontine angle (CPA) and a diagnosis of "auditory neuropathy/auditory dyssynchrony" was established. A microsurgical resection of the cyst wall and fenestration was performed by a retro sigmoid approach. This is the first case in the literature of auditory neuropathy (AN) in an infant caused by a cerebellopontine angle arachnoid cyst.