Meningiomas of the Skull Base — MCQs
In acoustic neuroma, cranial nerve to be involved earliest is
Which of the following statements about meningiomas is true?
Most common optic nerve tumor in children causing blindness:
Which primary brain parenchymal tumor is most commonly associated with calcifications seen on imaging studies?
The most common intracranial tumor in children is –
All of the following statements about cerebellar astrocytomas in paediatric age group are true, EXCEPT:
Statement 1 - A 59-year-old patient presents with flaccid bullae. Histopathology shows a suprabasal acantholytic split. Statement 2 - The row of tombstones appearance is diagnostic of Pemphigus vulgaris.
Which of the following is NOT typically associated with acute bacterial sinusitis?
What is the most common space-occupying lesion in the cerebellopontine angle?
CSF rhinorrhea is most commonly seen in fracture of which of the following bones?
Meningiomas of the Skull Base Indian Medical PG Practice Questions and MCQs
Question 1: In acoustic neuroma, cranial nerve to be involved earliest is
- A. Cranial nerve VIII (Correct Answer)
- B. Cranial nerve VII
- C. Cranial nerve IX
- D. Cranial nerve V
Explanation: ***Cranial nerve VIII*** - Acoustic neuromas (vestibular schwannomas) arise from the **Schwann cells** of the vestibular branch of the **eighth cranial nerve (vestibulocochlear nerve)** [1]. - Due to their origin, symptoms related to CN VIII, such as **unilateral hearing loss**, **tinnitus**, and **vertigo**, are typically the earliest to appear [1]. *Cranial nerve VII* - The **facial nerve (CN VII)** is anatomically close to the eighth nerve within the **internal auditory canal**, but its involvement usually occurs later as the tumor grows and compresses it [1]. - Early involvement of CN VII would primarily manifest as **facial weakness or paralysis** or taste disturbances [1]. *Cranial nerve IX* - The **glossopharyngeal nerve (CN IX)** is located more medially in the **cerebellopontine angle** and is typically affected only by larger tumors. - Symptoms would primarily include **dysphagia (difficulty swallowing)** or loss of taste on the posterior tongue. *Cranial nerve V* - The **trigeminal nerve (CN V)** is also situated in the cerebellopontine angle, further from the initial growth site of an acoustic neuroma. - Involvement of CN V would lead to **facial numbness**, pain, or weakness in the muscles of mastication, which are late manifestations.
Question 2: Which of the following statements about meningiomas is true?
- A. Approximately 5% of meningiomas are malignant.
- B. Arise from the dural layer
- C. Meningiomas are more common in women due to hormonal influences.
- D. 95% cure rate following total surgical resection of benign meningiomas (Correct Answer)
Explanation: ***95% cure rate following treatment*** - Meningiomas generally have a **high cure rate of approximately 95%** following surgical resection, especially when they are completely excised [1]. - They are typically **benign tumors**, resulting in favorable outcomes with appropriate management [1]. *Arise from arachnoid layer* - Meningiomas actually arise from **meningothelial cells** of the **arachnoid layer**, but this statement does not fully explain their pathogenesis. - This mischaracterization does not provide an accurate understanding of the tumor's origin and biology. *50% are malignant* - Most meningiomas are benign; only a small percentage, about **1-5%**, are classified as malignant. - Thus, stating that **50% are malignant** significantly overestimates the incidence of aggressive forms. *More common in men* - Meningiomas are more prevalent in **women**, especially those aged between 30-70 years, with a female-to-male ratio of approximately **3:1**. - This option is incorrect as it misrepresents the demographic distribution of the disease. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Central Nervous System, pp. 1316-1317.
Question 3: Most common optic nerve tumor in children causing blindness:
- A. Astrocytoma
- B. Craniopharyngioma
- C. Meningioma
- D. Glioma (Correct Answer)
Explanation: ***Glioma*** - **Optic pathway gliomas** (also called optic nerve gliomas) are the **most common primary tumors of the optic nerve in children**, accounting for approximately 66% of all optic nerve tumors in the pediatric population. - These are typically **low-grade pilocytic astrocytomas (WHO Grade I)** and are strongly associated with **neurofibromatosis type 1 (NF1)** in 15-30% of cases [1]. - They cause **progressive visual loss** leading to **blindness**, and may present with **proptosis**, strabismus, and optic disc swelling. - The term "glioma" is the **standard clinical nomenclature** used for these tumors in pediatric ophthalmology and neuro-oncology. *Astrocytoma* - While optic nerve gliomas are histologically **pilocytic astrocytomas** [1], the accepted clinical term for this entity is **"optic nerve glioma"** or **"optic pathway glioma"**, not simply "astrocytoma." - Using "astrocytoma" alone is too generic and could refer to various brain astrocytomas (diffuse, anaplastic, glioblastoma) rather than the specific entity of optic nerve tumors [1]. - In clinical practice and literature, these are consistently referred to as **optic gliomas**. *Craniopharyngioma* - This is a **suprasellar tumor** arising from Rathke's pouch remnants, causing **bitemporal hemianopsia** due to **chiasmal compression**. - It does **not originate from the optic nerve** itself—it compresses the optic chiasm from above. - While common in children, it is a chiasmal/suprasellar lesion, not an optic nerve tumor. *Meningioma* - **Optic nerve sheath meningiomas** are rare in children and primarily affect **adults (peak in 40s)**, especially women. - These arise from meningothelial cells of the optic nerve sheath and cause **progressive painless visual loss** and **optic disc edema**. - In children, meningiomas represent **<2% of CNS tumors**, making them an uncommon cause of pediatric optic nerve pathology. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Manifestations Of Central And Peripheral Nervous System Disease, pp. 724-726.
Question 4: Which primary brain parenchymal tumor is most commonly associated with calcifications seen on imaging studies?
- A. Oligodendroglioma (Correct Answer)
- B. Astrocytoma
- C. Medulloblastoma
- D. Craniopharyngioma
Explanation: ***Oligodendroglioma*** - **Oligodendrogliomas** are highly associated with **calcifications**, which are observed in **70-90% of cases** on imaging studies like CT scans. - The calcifications appear as **coarse, punctate, or nodular** and are typically located in the **cerebral hemispheres** (frontal and temporal lobes most common). - This is the **classic imaging finding** that helps differentiate oligodendrogliomas from other glial tumors. *Astrocytoma* - While some astrocytomas can calcify, especially low-grade forms, they are **not as consistently calcified** as oligodendrogliomas. - Calcifications occur in only **20-30% of cases** and are typically less prominent. *Medulloblastoma* - **Medulloblastomas** are most commonly found in the **cerebellum** (posterior fossa) and primarily affect children. - Calcifications are **infrequent**, occurring in approximately **10-20% of cases**, and are usually small and inconspicuous. *Craniopharyngioma* - **Craniopharyngiomas** are benign tumors arising from Rathke's pouch remnants, located in the **suprasellar region**. - While they do frequently calcify (especially in children), they are **extra-axial tumors**, not primary brain parenchymal tumors. - This question specifically asks about parenchymal brain tumors, making oligodendroglioma the correct answer among glial neoplasms.
Question 5: The most common intracranial tumor in children is –
- A. Meningioma
- B. Lymphangioma
- C. Glioma (Correct Answer)
- D. Medulloblastoma
Explanation: ***Glioma*** - **Gliomas** are the most common type of intracranial tumor in children, accounting for approximately **50-60%** of all pediatric brain tumors. This broad category includes tumors like astrocytomas (e.g., **pilocytic astrocytoma**), ependymomas, and brainstem gliomas. - The most common subtype of glioma in children is the **pilocytic astrocytoma**, which often arises in the cerebellum or optic pathway. - Other common gliomas include **ependymomas** (arising in the ventricular system) and **diffuse brainstem gliomas**. *Meningioma* - **Meningiomas** are tumors arising from the meninges, the membranes surrounding the brain and spinal cord, and are **rare** in children. - These tumors are typically seen in **middle-aged to older adults**, and their occurrence in pediatric populations is uncommon, accounting for less than **2%** of pediatric brain tumors. *Lymphangioma* - A **lymphangioma** is a benign malformation of the lymphatic system, most commonly found in the **head and neck region** (e.g., cystic hygroma), not within the brain parenchyma. - It is a tumor of lymphatic vessels and is **not an intracranial brain tumor** in the typical sense. *Medulloblastoma* - **Medulloblastoma** is the most common **malignant** brain tumor in children and the most common **posterior fossa tumor** in the pediatric population. - However, when considering **all intracranial tumors** (both benign and malignant), **gliomas as a category** are more common overall than medulloblastomas alone. - Medulloblastomas arise from the cerebellum and account for approximately **15-20%** of pediatric brain tumors.
Question 6: All of the following statements about cerebellar astrocytomas in paediatric age group are true, EXCEPT:
- A. These tumors have a good prognosis
- B. These tumours are more common in females (Correct Answer)
- C. These are usually Low grade tumors
- D. These are more commonly seen in the 1st and 2nd decades
Explanation: ***These tumours are more common in females*** - Cerebellar astrocytomas, particularly **pilocytic astrocytomas (PA)**, show a slight male predominance [1], or equal sex distribution, rather than being more common in females. - This statement is the exception to the generally true characteristics of cerebellar astrocytomas in children. *These tumors have a good prognosis* - **Pilocytic astrocytomas (PAs)**, which constitute the majority of pediatric cerebellar astrocytomas, are generally **low-grade (WHO grade I)** tumors. - They have an **excellent prognosis** following gross total resection, with high 5-year survival rates. *These are usually Low grade tumors* - The vast majority of cerebellar astrocytomas in children are **pilocytic astrocytomas**, which are classified as **WHO grade I** [2]. - This low-grade nature contributes significantly to their favorable prognosis compared to higher-grade astrocytomas. *These are more commonly seen in the 1st and 2nd decades* - Pediatric cerebellar astrocytomas primarily affect **children and young adults**, with the peak incidence observed in the **first two decades of life** [1], [2]. - They are among the most common brain tumors in this age group, typically presenting between the ages of 5 and 15 years. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Manifestations Of Central And Peripheral Nervous System Disease, pp. 725-726. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Central Nervous System, pp. 1319-1320.
Question 7: Statement 1 - A 59-year-old patient presents with flaccid bullae. Histopathology shows a suprabasal acantholytic split. Statement 2 - The row of tombstones appearance is diagnostic of Pemphigus vulgaris.
- A. Statements 1 & 2 are correct, 2 is not explaining 1 (Correct Answer)
- B. Statements 1 and 2 are correct and 2 is the correct explanation for 1
- C. Statements 1 and 2 are incorrect
- D. Statement 1 is incorrect
Explanation: ***Correct: Statements 1 & 2 are correct, 2 is not explaining 1*** **Analysis of Statement 1:** - A 59-year-old patient with **flaccid bullae** and **suprabasal acantholytic split** on histopathology is the classic presentation of **Pemphigus vulgaris** - The flaccid (easily ruptured) nature of bullae distinguishes it from tense bullae seen in bullous pemphigoid - The suprabasal location of the split (just above the basal layer) with acantholysis (loss of cell-to-cell adhesion) is pathognomonic - **Statement 1 is CORRECT** ✓ **Analysis of Statement 2:** - The **"row of tombstones" or "tombstone appearance"** is indeed a diagnostic histopathological feature of Pemphigus vulgaris - This appearance results from basal keratinocytes remaining attached to the basement membrane while suprabasal cells separate due to acantholysis - The intact basal cells standing upright resemble a row of tombstones - **Statement 2 is CORRECT** ✓ **Does Statement 2 explain Statement 1?** - Statement 2 describes a **histopathological appearance** (tombstone pattern) that is a **consequence** of the suprabasal split - However, it does NOT explain the **underlying cause** of the flaccid bullae or the suprabasal split - The true explanation involves **IgG autoantibodies against desmoglein 3 (and desmoglein 1)**, which attack intercellular adhesion structures (desmosomes), causing **acantholysis** - Therefore, **Statement 2 does NOT explain Statement 1** ✗ *Incorrect: Statement 2 is the correct explanation for Statement 1* - While both statements describe features of Pemphigus vulgaris, the tombstone appearance is a descriptive finding, not an explanatory mechanism *Incorrect: Statements 1 and 2 are incorrect* - Both statements are medically accurate descriptions of Pemphigus vulgaris features *Incorrect: Statement 1 is incorrect* - Statement 1 correctly describes the cardinal clinical and histopathological features of Pemphigus vulgaris
Question 8: Which of the following is NOT typically associated with acute bacterial sinusitis?
- A. Purulent nasal discharge
- B. Epistaxis (Correct Answer)
- C. Facial pain
- D. Fever
Explanation: ***Epistaxis*** - While possible due to **mucosal inflammation** or irritation from forceful blowing, **epistaxis (nosebleeds)** is not considered a typical or primary symptom of acute bacterial sinusitis. - The main symptoms revolve around pressure, discharge, and systemic signs of infection. *Purulent nasal discharge* - This is a hallmark symptom of acute bacterial sinusitis, indicating the presence of **bacterial infection** and inflammation in the sinuses. - The discharge is often thick, colored (yellow, green), and can be accompanied by a **foul odor**. *Facial pain* - **Facial pain** or pressure, especially around the cheeks, forehead, or eyes, is a characteristic symptom stemming from inflammation and fluid accumulation within the **sinus cavities**. - This pain often worsens when bending forward. *Fever* - **Fever** is a systemic sign of infection and is commonly present in acute bacterial sinusitis, especially in more severe cases. - It indicates the body's immune response to the bacterial invasion.
Question 9: What is the most common space-occupying lesion in the cerebellopontine angle?
- A. Meningioma
- B. Glioma
- C. Neurofibroma
- D. Acoustic neuroma (Correct Answer)
Explanation: **Explanation:** The **Cerebellopontine Angle (CPA)** is a potential space in the posterior cranial fossa. The correct answer is **Acoustic Neuroma** (also known as Vestibular Schwannoma), which accounts for approximately **80–85%** of all CPA tumors. 1. **Acoustic Neuroma (Correct):** These are benign, slow-growing tumors arising from the Schwann cells of the vestibular nerve (most commonly the inferior vestibular nerve). They typically present with unilateral sensorineural hearing loss, tinnitus, and dysequilibrium. 2. **Meningioma (Incorrect):** This is the **second most common** CPA lesion, accounting for about 10–15% of cases. Unlike acoustic neuromas, they often do not widen the internal auditory canal (IAC) and may show calcification or a "dural tail" on MRI. 3. **Epidermoid Cyst (Incorrect):** These are the third most common CPA lesions (approx. 5%). They are congenital and characterized by a "pearly" appearance and restricted diffusion on MRI. 4. **Neurofibroma (Incorrect):** While associated with Neurofibromatosis Type 1, the tumors in the CPA (specifically in NF-2) are actually **Schwannomas**, not neurofibromas. 5. **Glioma (Incorrect):** These are primary brain parenchyma tumors (e.g., brainstem gliomas) and are rarely primary occupants of the CPA space. **NEET-PG High-Yield Pearls:** * **Gold Standard Investigation:** Contrast-enhanced MRI (Gadolinium) is the investigation of choice. * **Bilateral Acoustic Neuromas:** Pathognomonic for **Neurofibromatosis Type 2 (NF-2)**. * **Audiometry Finding:** Characterized by "Retrocochlear" pathology (Poor speech discrimination score out of proportion to pure tone loss and absence of recruitment). * **Order of Frequency in CPA:** Acoustic Neuroma > Meningioma > Epidermoid > Facial Nerve Schwannoma.
Question 10: CSF rhinorrhea is most commonly seen in fracture of which of the following bones?
- A. Cribriform plate (Correct Answer)
- B. Temporal bone
- C. Nasal bone
- D. Occipital bone
Explanation: **Explanation:** **Cribriform plate (Option A)** is the correct answer because it is the thinnest part of the anterior skull base and is intimately fused with the underlying dura mater. Due to this anatomical fragility, even minor head trauma can result in a dural tear. Since the cribriform plate forms the roof of the nasal cavity, any breach allows Cerebrospinal Fluid (CSF) to leak directly into the nose, manifesting as **CSF rhinorrhea**. **Analysis of Incorrect Options:** * **Temporal bone (Option B):** Fractures here (especially longitudinal) more commonly lead to **CSF otorrhea** (leakage through the ear). While CSF rhinorrhea can occur if the tympanic membrane is intact and fluid drains via the Eustachian tube, it is statistically less common than leaks from the anterior cranial fossa. * **Nasal bone (Option C):** These are the most common facial fractures, but they are extracranial. Unless the fracture extends superiorly into the frontal or ethmoid bones, it does not involve the dural sac. * **Occipital bone (Option D):** Fractures here involve the posterior cranial fossa. These are more likely to cause cranial nerve palsies or cerebellar injury rather than rhinorrhea. **High-Yield Clinical Pearls for NEET-PG:** * **Most common site of spontaneous CSF leak:** Tegmen tympani or Ethmoid roof. * **Most common site of traumatic CSF leak:** Cribriform plate/Ethmoid bone. * **Confirmatory Test:** **Beta-2 Transferrin** (most specific) or Beta-trace protein. * **Target Sign/Halo Sign:** Seen when CSF is mixed with blood on a paper/linen (CSF migrates further, forming a clear outer ring). * **Management:** Initial conservative management (bed rest, head elevation, avoiding straining). If persistent, endoscopic endonasal repair is the gold standard.
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