Profound bilateral sensorineural hearing loss. Internal Auditory Canal: There is an arachnoid cyst in the right cerebellomedullary cistern that measures up to 20 mm and abuts the vestibular nerve without appreciable displacement. The bilateral vestibular nerves are otherwise unremarkable. The cochlear and facial nerves are intact bilaterally. The bilateral inner ear structures are intact. Brain: The brain parenchyma and pituitary gland appear unremarkable. There is no evidence of intracranial hemorrhage or acute infarct. There is no abnormal intracranial enhancement. The ventricles and basal cisterns are normal in size and configuration. There is no midline shift or herniation. The major cerebral flow voids are intact. The orbits and scalp soft tissues are grossly unremarkable. There is mild scattered paranasal sinus mucosal thickening. There is plagiocephaly.
A right cerebellomedullary cistern arachnoid cyst that measures up to 20 mm and abuts the vestibular nerve without appreciable displacement. Otherwise, no evidence of cochlear nerve deficiency or inner ear anomalies.