Acoustic Neuroma — MCQs

10 questions

The most common tumor of the cerebellopontine angle is -

A 25-year-old woman presents with episodes of dizziness, tinnitus, and hearing loss in the right ear. What is the most likely diagnosis?

A 35-year-old man presents with progressive right-sided hearing loss, balance difficulties, and headaches. MRI reveals an enhancing mass in the cerebellopontine angle. Most likely diagnosis?

Tests of SNHL are characterized by all EXCEPT

In acoustic neuroma, which cranial nerve is involved earliest?

Most definitive treatment for large symptomatic acoustic neuroma is

True about acoustic neuroma:

A patient has multiple meningiomas, acoustic neuroma and hyperpigmented skin lesions; most likely diagnosis is –

All of the following cranial nerves are involved in Acoustic neuroma, except?

Q10

If in a patient of acoustic neuroma, corneal reflex is absent it implies involvement of cranial nerve:

Acoustic Neuroma Indian Medical PG Practice Questions and MCQs

Question 1: The most common tumor of the cerebellopontine angle is -

A. None of the options
B. Meningioma
C. Acoustic neuroma (Correct Answer)
D. Neurofibroma

Explanation: ***Acoustic neuroma*** - Acoustic neuromas, also known as **vestibular schwannomas**, are the most common tumors of the **cerebellopontine angle (CPA)**, accounting for **80-90%** of CPA tumors. [1] - They arise from the **Schwann cells** of the **vestibular portion of cranial nerve VIII** (vestibulocochlear nerve). [1] - Typical clinical presentation includes **progressive unilateral sensorineural hearing loss**, **tinnitus**, **vertigo**, and in advanced cases, involvement of adjacent cranial nerves (V and VII). *Meningioma* - Meningiomas are the **second most common** CPA tumor (10-15% of cases), originating from the **arachnoid cap cells**. [1] - They typically grow more slowly than acoustic neuromas and may present with different cranial nerve deficits depending on their exact location. - On imaging, they show characteristic **dural tail sign** and homogeneous enhancement. *Neurofibroma* - While neurofibromas can affect cranial nerves, they are **far less common** in the CPA than acoustic neuromas. [1] - They are often associated with **Neurofibromatosis type 1 (NF1)**, whereas bilateral acoustic neuromas are characteristic of **NF2**. [1] - Isolated CPA neurofibromas are rare. *None of the options* - This option is incorrect as **acoustic neuroma** is the well-established most common tumor of the cerebellopontine angle. [1] - This is a fundamental concept in neurology, neurosurgery, and pathology. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Manifestations Of Central And Peripheral Nervous System Disease, pp. 727-728.

Question 2: A 25-year-old woman presents with episodes of dizziness, tinnitus, and hearing loss in the right ear. What is the most likely diagnosis?

A. Labyrinthitis
B. Ménière's disease (Correct Answer)
C. Acoustic neuroma
D. Benign paroxysmal positional vertigo

Explanation: ***Ménière's disease*** - This condition is characterized by a classic triad of **episodic vertigo (dizziness)**, fluctuating **sensorineural hearing loss**, and **tinnitus**, often accompanied by aural fullness, typically affecting one ear. - The symptoms arise from an accumulation of **endolymph** in the inner ear, leading to increased pressure and dysfunction. *Labyrinthitis* - **Labyrinthitis** is an inflammation of the inner ear, usually viral, causing sudden, severe **vertigo** potentially with hearing loss and tinnitus. - Unlike Meniere's disease, **hearing loss** and **tinnitus** in labyrinthitis are usually constant rather than episodic or fluctuating. *Acoustic neuroma* - An **acoustic neuroma** (vestibular schwannoma) is a benign tumor on the eighth cranial nerve, often causing **gradual, progressive unilateral hearing loss**, tinnitus, and **balance issues**, but typically not episodic severe dizziness. - While it can cause hearing loss and tinnitus, the **episodic nature of vertigo** is less common than in Ménière's disease. *Benign paroxysmal positional vertigo* - **BPPV** is characterized by sudden, **brief episodes of vertigo** triggered by specific head movements, caused by dislodged **otoconia** in the semicircular canals. - Critically, BPPV does **not** typically cause associated **hearing loss or tinnitus**, which are prominent symptoms in the presented case.

Question 3: A 35-year-old man presents with progressive right-sided hearing loss, balance difficulties, and headaches. MRI reveals an enhancing mass in the cerebellopontine angle. Most likely diagnosis?

A. Vestibular neuritis
B. Otosclerosis
C. Meniere's disease
D. Acoustic neuroma (Correct Answer)

Explanation: ***Acoustic neuroma*** - The combination of **progressive unilateral hearing loss**, **balance difficulties**, and **headaches**, along with an **enhancing mass in the cerebellopontine angle** on MRI, is highly characteristic of an acoustic neuroma (vestibular schwannoma). - These are benign tumors that arise from the **vestibulocochlear nerve (cranial nerve VIII)**, causing compression of adjacent structures. *Vestibular neuritis* - This condition presents with **sudden onset, severe vertigo** often triggered by head movement, but it is typically **acute and self-limiting**, without a progressive course or an intracranial mass. - **Hearing is usually spared** in vestibular neuritis, which is inconsistent with the patient's progressive hearing loss. *Otosclerosis* - Otosclerosis is a disease of abnormal bone remodeling in the middle ear, leading to **progressive conductive hearing loss**, often bilateral. - It does **not typically cause balance difficulties** or present as a **cerebellopontine angle mass** on MRI. *Meniere's disease* - Characterized by a triad of **fluctuating hearing loss**, **episodic vertigo**, and **tinnitus**, often with a sensation of aural fullness. - While it causes hearing loss and balance issues, it does **not involve an enhancing mass** in the cerebellopontine angle.

Question 4: Tests of SNHL are characterized by all EXCEPT

A. Positive Rinne test
B. Speech discrimination is good (Correct Answer)
C. Weber lateralised to better ear
D. More often involving high frequencies

Explanation: ***Speech discrimination is good*** - In **sensorineural hearing loss (SNHL)**, damage to the cochlea or auditory nerve specifically impairs the processing of complex sound signals. - This typically leads to **poor speech discrimination**, particularly in noisy environments, making it difficult to understand spoken words even when the volume is adequate. - **This is NOT characteristic of SNHL**, making it the correct answer to this EXCEPT question. ***Positive Rinne test*** - A **positive Rinne test** (air conduction > bone conduction) **is characteristic of SNHL**. - In SNHL, both air and bone conduction are reduced equally, but air conduction remains better than bone conduction, maintaining the positive Rinne pattern. - There is **no air-bone gap** in SNHL (unlike conductive hearing loss where Rinne becomes negative). ***Weber lateralised to better ear*** - In **unilateral SNHL**, the **Weber test lateralizes to the better-hearing ear** because the healthy cochlea perceives the sound vibration more strongly. - The damaged ear is less able to detect the bone-conducted sound, causing the perception that the sound is louder in the unaffected ear. - **This is characteristic of SNHL**. ***More often involving high frequencies*** - **SNHL often affects high frequencies first** due to specific vulnerabilities of the **basal turn of the cochlea** to age-related degeneration, noise exposure, and ototoxic drugs. - This pattern of hearing loss is common in **presbycusis** and noise-induced hearing loss. - **This is characteristic of SNHL**.

Question 5: In acoustic neuroma, which cranial nerve is involved earliest?

A. CN V
B. CN VII
C. CN VIII (Correct Answer)
D. CN X

Explanation: ***CN VIII*** - An **acoustic neuroma** (also known as a **vestibular schwannoma**) originates from the **Schwann cells** of the **vestibulocochlear nerve (CN VIII)**. - Due to its origin, symptoms related to **hearing loss**, **tinnitus**, and **balance issues** (all functions of CN VIII) are typically the earliest to manifest [1]. *CN V* - The **trigeminal nerve (CN V)** is responsible for **facial sensation** and **mastication**. - Compression of CN V usually occurs in later stages of acoustic neuroma growth, leading to **facial numbness** or **pain**. *CN VII* - The **facial nerve (CN VII)** controls **facial expressions** and taste sensation in the anterior two-thirds of the tongue. - **Facial weakness** or **paralysis** due to CN VII involvement typically occurs after significant tumor growth, as the nerve runs adjacent to the acoustic neuroma [1]. *CN X* - The **vagus nerve (CN X)** is involved in diverse functions including **swallowing**, **speech**, and **autonomic regulation** of organs like the heart and digestive tract. - **Vagal nerve** symptoms such as **dysphagia** or **hoarseness** are extremely rare in acoustic neuromas and would indicate a very extensive tumor likely compressing structures much more distant from the primary site.

Question 6: Most definitive treatment for large symptomatic acoustic neuroma is

A. Steroids
B. Radiotherapy
C. Anti-neoplastic drugs
D. Surgery (Correct Answer)

Explanation: ***Surgery*** - **Surgical resection** is the most definitive treatment for **large, symptomatic acoustic neuromas** (typically >3 cm), especially those causing **mass effect** on the brainstem and cerebellum. - It aims for **complete tumor removal** to alleviate symptoms (hearing loss, facial nerve dysfunction, brainstem compression) and prevent further neurological compromise. - Surgical approaches include **translabyrinthine**, **retrosigmoid**, or **middle cranial fossa** approaches depending on tumor size and hearing status. *Steroids* - **Steroids** may be used to manage acute symptoms like **edema** or inflammation associated with the tumor, but they are not a definitive treatment. - They do not address the underlying tumor growth or remove the mass. - Used only as **temporary symptomatic relief** or perioperative adjunct. *Radiotherapy* - **Stereotactic radiosurgery** (Gamma Knife, CyberKnife) is effective for **small to medium-sized tumors** (<3 cm) with good tumor control rates. - For **large tumors**, radiotherapy is **insufficient** as it only aims to **control tumor growth** rather than remove the mass, and cannot provide immediate decompression. - Large tumors with mass effect require **surgical decompression** for definitive management. *Anti-neoplastic drugs* - **Anti-neoplastic drugs** (chemotherapy) are generally **ineffective** against acoustic neuromas, which are **benign vestibular schwannomas**. - They are typically reserved for malignant tumors or specific genetic syndromes (e.g., bevacizumab in NF2-related schwannomas), but not for standard sporadic acoustic neuromas. - Chemotherapy is **not a definitive treatment** for these benign tumors.

Question 7: True about acoustic neuroma:

A. Arises from vestibular nerve (Correct Answer)
B. Malignant tumour
C. Upper pole compresses IX,X,XI nerves
D. Lower pole compresses trigeminal cranial nerve

Explanation: ***Arises from vestibular nerve*** - An **acoustic neuroma**, also known as a **vestibular schwannoma**, is a benign tumor that originates from the **Schwann cells** of the **vestibular nerve (cranial nerve VIII)**. - This tumor typically grows in the **internal auditory canal** and cerebellopontine angle. *Malignant tumour* - Acoustic neuromas are almost always **benign tumors**, meaning they are non-cancerous and do not typically spread to other parts of the body. - While they are benign, their growth can compress adjacent nerves and brain structures, leading to significant neurological deficits. *Upper pole compresses IX,X,XI nerves* - The **glossopharyngeal (IX), vagus (X), and accessory (XI) nerves** originate lower in the brainstem and are more commonly compressed by tumors in the **jugular foramen** region, not typically by the upper pole of an acoustic neuroma. - An acoustic neuroma primarily affects the **vestibulocochlear nerve (VIII)** and, if large enough, the **facial nerve (VII)** and **trigeminal nerve (V)** in the **cerebellopontine angle**. *Lower pole compresses trigeminal cranial nerve* - The **trigeminal nerve (V)** is located more superiorly and medially in the **cerebellopontine angle** relative to the usual growth pattern of an acoustic neuroma. - Compression of the trigeminal nerve by an acoustic neuroma is more likely to occur with a **large tumor** expanding into the superior part of the cerebellopontine angle, rather than by its lower pole.

Question 8: A patient has multiple meningiomas, acoustic neuroma and hyperpigmented skin lesions; most likely diagnosis is –

A. Neurofibromatosis (Correct Answer)
B. Von Hippel lindau disease
C. Sturge weber syndrome
D. Tuberous sclerosis

Explanation: ***Neurofibromatosis*** - The combination of **multiple meningiomas**, **acoustic neuroma** (specifically bilateral in NF2) [1], and **hyperpigmented skin lesions** (cafe-au-lait spots in NF1, or multiple cutaneous neurofibromas) is highly characteristic of neurofibromatosis. - This presentation suggests either **Neurofibromatosis type 1 (NF1)** with meningiomas (less common but possible) or, more strongly, **Neurofibromatosis type 2 (NF2)** due to the bilateral acoustic neuromas and the presence of meningiomas, with hyperpigmentation being a variable feature [1]. *Von Hippel-Lindau disease* - This disorder is characterized by **hemangioblastomas** of the retina and central nervous system, **renal cell carcinoma**, and **pheochromocytomas**. - It does not typically involve meningiomas, acoustic neuromas, or hyperpigmented skin lesions. *Sturge-Weber syndrome* - This is a neurocutaneous disorder featuring a **port-wine stain (facial nevus flammeus)**, leptomeningeal angioma, and **glaucoma**. - The clinical picture of meningiomas, acoustic neuroma, and hyperpigmented skin lesions does not align with Sturge-Weber syndrome. *Tuberous sclerosis* - This condition is characterized by the growth of numerous **benign tumors in many different organs**, including the brain (tubers, subependymal giant cell astrocytomas), skin (facial angiofibromas, shagreen patches, ash-leaf spots), kidneys (angiomyolipomas), and heart (rhabdomyomas). - While it has **skin lesions** and **brain tumors**, these are distinct from meningiomas and acoustic neuromas, which are not typical features.

Question 9: All of the following cranial nerves are involved in Acoustic neuroma, except?

A. Vagus
B. Oculomotor (Correct Answer)
C. Glossopharyngeal
D. Facial

Explanation: ***Oculomotor*** - The **oculomotor nerve (CN III)** is located in the midbrain, far from the cerebellopontine angle where acoustic neuromas typically grow. - Its involvement is not characteristic of an acoustic neuroma and would suggest a different intracranial pathology. *Vagus* - The **vagus nerve (CN X)** exits the brainstem near the cerebellopontine angle, and can be affected by larger acoustic neuromas. - Compression can lead to symptoms like **dysphagia**, **hoarseness**, or **vocal cord paralysis**. *Glossopharyngeal* - The **glossopharyngeal nerve (CN IX)** is also in close proximity to the cerebellopontine angle. - Compression can result in symptoms such as **dysphagia**, **loss of taste** in the posterior tongue, or **loss of gag reflex**. *Facial* - The **facial nerve (CN VII)** is anatomically very close to the vestibulocochlear nerve (CN VIII) within the internal auditory canal. - **Facial nerve palsy**, characterized by **facial weakness** or **paralysis**, is a common symptom of acoustic neuromas due to direct compression or surgical manipulation.

Question 10: If in a patient of acoustic neuroma, corneal reflex is absent it implies involvement of cranial nerve:

A. None of the options
B. 5th (Correct Answer)
C. Both
D. 7th

Explanation: ***5th*** - The **corneal reflex** tests the integrity of the **trigeminal nerve (CN V)** for the afferent (sensory) pathway, detecting touch on the cornea [1]. Its absence indicates dysfunction of this nerve. - An **acoustic neuroma**, growing in the **cerebellopontine angle**, can compress adjacent cranial nerves, including the trigeminal nerve, leading to sensory deficits like an absent corneal reflex. *None of the options* - This option is incorrect because the **corneal reflex** directly evaluates specific cranial nerves, and its absence strongly points to involvement of one or more of them. - The symptoms described are classic neurological findings that can be localized to a specific nerve. *Both* - While both the trigeminal (CN V) and facial (CN VII) nerves are involved in the corneal reflex, the **afferent limb (sensory perception)** is primarily mediated by the trigeminal nerve [1]. - The efferent limb (motor response of blinking) is mediated by the facial nerve, but the absence of the reflex points to the sensory input problem [1]. *7th* - The **facial nerve (CN VII)** is responsible for the **efferent (motor) component** of the corneal reflex, causing the eyelids to close [1]. - While a lesion of the facial nerve would impair the blinking response, the primary issue when the stimulus is not perceived (leading to an absent reflex altogether) is generally a problem with the **trigeminal nerve's sensory function**.

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