Pitfalls in the diagnosis of acoustic neuroma

Abstract

The patient with an acoustic neuroma may present to the otologist with a variety of clinical features. Classically these include a retrocochlear pattern of sensorineural hearing loss, reduced vestibular response on caloric testing and radiological asymmetry of the internal auditory canals (IAC). The absence of any or all of these features, however, does not exclude the presence of tumour. Five cases are presented to illustrate the potential for diagnostic delay unless a routine battery of investigations is undertaken in patients with neuro-otological disorders. All patterns of subjective audiometry are encountered, auditory brain stem response testing may be unreliable where hearing loss is profound, vestibular testing is normal in half of small tumours and the intracanalicular tumour may be radiologically undetectable unless IAC meatography is employed.

Diagnostic delays in vestibular schwannoma

“…The symptoms can often be considered mundane, especially when compared with the rarity of vestibular schwannoma. Also, screening tests used to indicate the need for MRI can be misleading; audiometry and calorimetric testing of vestibular function can be normal, especially in the case of small tumours, and testing for brainstem auditory evoked potentials may be unreliable when hearing loss is profound 10 …”