Intracochlear schwannoma : Tumor removal via subtotal cochleoectomy and partial cochlear reconstruction with preservation of semicircular canal function.

ABSTRACT

We report about a patient, who in 2005, as a 37-year-old, experienced a sudden, mild to moderate, mid-frequency sensorineural hearing loss in the right ear, along with tinnitus and mild dizziness. MRI of the temporal bone revealed a very small (1 mm) enhancing lesion in the second turn of the right cochlea after injection of contrast medium. Hearing gradually deteriorated, with complete hearing loss in 2015. At this time, an MRI scan showed a lesion completely filling the cochlea.The tumor was removed through a subtotal cochleoectomy. The cochlea was partially reconstructed with cartilage and fascia. A cochlea implant dummy electrode was inserted as a placeholder in order to try to preserve a channel within the most likely fibrosing "neocochlea" during follow-up MRI examinations.Vestibular function tests 2 months postoperatively showed preserved caloric excitability and a normal vestibulo-ocular reflex (video head impulse test, vHIT) in all three planes. The patient is free of vertigo.Intralabyrinthine schwannomas (ILS) are a rare differential diagnosis of sudden hearing loss. Surgical removal of an intracochlear ILS through partial or subtotal cochleoectomy with preservation of vestibular function is possible.