A 54-year-old man presents to his physician with a 1-year history of progressive hearing loss in his right ear. He also reports a constant, high-pitched hissing sound in the same ear. He denies any episodes of vertigo but mentions a vague sense of imbalance when walking in the dark. Past medical history is significant for hypertension and hyperlipidemia. On physical examination, the Weber test lateralizes to the left ear, and the Rinne test shows air conduction greater than bone conduction bilaterally. Cranial nerve examination reveals slightly decreased sensation to light touch over the right side of his face. There is no facial weakness.
Which of the following is the most likely diagnosis?
The correct answer is:
A) Acoustic neuroma
The patient is presenting with an acoustic neuroma, also called a vestibular schwannoma. This is a benign tumor of the Schwann cells involving the vestibular portion of cranial nerve VIII within the internal auditory canal. The hallmark presentation is asymmetric sensorineural hearing loss and tinnitus. Unlike Meniere disease, vertigo is rarely a prominent feature because the slow growth of the tumor allows the central nervous system to compensate for the gradual loss of vestibular function. As the tumor expands out of the internal auditory canal into the cerebellopontine angle, it can compress the trigeminal nerve (CN V), leading to a diminished corneal reflex or facial numbness, as seen in this patient.
Answer choice B: Cholesteatoma, is incorrect. Cholesteatoma is an overgrowth of desquamated keratinized epithelium in the middle ear. While it causes hearing loss, it is typically conductive, so the Weber test would lateralize to the affected ear. It is often associated with chronic ear drainage (otorrhea).
Answer choice C: Meniere disease, is incorrect. Meniere disease presents with a classic triad of episodic vertigo, fluctuating low-frequency hearing loss, and aural fullness. This patient’s hearing loss is progressive and constant rather than episodic, and he lacks significant vertigo.
Answer choice D: Otosclerosis, is incorrect. Otosclerosis is a condition of bony overgrowth of the stapes footplate, leading to conductive hearing loss. It typically presents in younger patients in their 20s–30s and often has a strong familial component.
Answer choice E: Presbycusis, is incorrect. Presbycusis is age-related sensorineural hearing loss. While common in older adults, it is almost always bilateral and symmetric, affecting higher frequencies first. Asymmetric hearing loss is a red flag that requires imaging to rule out a retrocochlear lesion like a schwannoma.
Key Learning Point
An acoustic neuroma (vestibular schwannoma) should be suspected in any patient with unilateral or asymmetric sensorineural hearing loss and tinnitus. If the tumor is large, it may involve CN V (loss of facial sensation) or CN VII (facial weakness). The gold standard for diagnosis is gadolinium-enhanced MRI of the internal auditory canals. Patients with bilateral acoustic neuromas should be evaluated for Neurofibromatosis type 2.
