CNS Tumors — MCQs

10 questions

Which of the following is the most common cause of a mixed cystic and solid suprasellar mass seen on cranial MR scan of a 10-year-old child:

What is the most common cerebellar tumor in children?

A child presented to the casualty department with fever, unconsciousness, and papilledema. What is the next step?

Which of the following statements about astrocytoma is false?

The most common intracranial tumor in children is –

A 10 year old child presented with headache, vomiting, gait instability and diplopia. On examination he had papilledema and gait ataxia. The most probable diagnosis is –

Amount of ORS to be given in the first 4 hours to a child with some dehydration is

A 2 year old child is seen on a routine visit in the pediatric clinic. Abdominal examination demonstrates a palpable, non-tender mass on the left side of the abdomen. The mother had no idea the mass was present and the pediatrician did not note the presence of the mass at the child's 18-month's visit for immunisation. Physical examination is otherwise unremarkable. If a CT guided biopsy of the mass were performed, which of the following histological patterns would be most suggestive of the likely diagnosis?

Which of the following is the most frequent primary malignant tumor of the CNS?

Q10

A 7 – year old boy presented with abdominal pain, vomiting, oliguria, and periorbital puffiness following chemotherapy. Investigations reveal hyperuricemia, raised creatinine levels, and hyperkalemia. What is the next best step in the management of this condition ?

CNS Tumors Indian Medical PG Practice Questions and MCQs

Question 1: Which of the following is the most common cause of a mixed cystic and solid suprasellar mass seen on cranial MR scan of a 10-year-old child:

A. Optic chiasma glioma
B. Pituitary Adenoma
C. Craniopharyngioma (Correct Answer)
D. Germinoma

Explanation: ***Craniopharyngioma*** * **Craniopharyngiomas** are the most common cause of a mixed cystic and solid suprasellar mass in children, often presenting with calcifications. * These tumors typically arise from Rathke's pouch remnants and can cause symptoms related to **pituitary dysfunction** and **visual field defects**. *Optic chiasma glioma* * **Optic chiasma gliomas** usually present as solid masses, although they can sometimes have cystic components. * They are more commonly associated with **Neurofibromatosis type 1** and primarily cause visual symptoms. *Pituitary Adenoma* * **Pituitary adenomas** are rare in children and typically present as purely solid masses, although cystic degeneration can occur. * They are more common in adults and often cause symptoms of **hormonal overproduction** or hypopituitarism. *Germinoma* * **Germinomas** are usually solid and homogenously enhancing tumors, sometimes with small cystic areas. * They are frequently located in the **pineal region** or suprasellar region and can cause hydrocephalus or endocrine dysfunction.

Question 2: What is the most common cerebellar tumor in children?

A. Ependymoma
B. Medulloblastoma (Correct Answer)
C. PNET
D. Astrocytoma

Explanation: ***Medulloblastoma*** - **Medulloblastoma** is the most common **malignant** cerebellar tumor in children, accounting for about 20% of all childhood brain tumors [2]. - In the context of this question, medulloblastoma is considered the "most common cerebellar tumor" as it is the most frequently encountered **malignant** tumor requiring aggressive treatment. - These tumors arise from neuroectodermal cells in the cerebellum and are typically **highly aggressive**, often spreading through the cerebrospinal fluid (CSF) pathways [1], [2]. - Peak incidence is between 5-9 years of age, with a male predominance [1]. *Astrocytoma* - **Cerebellar pilocytic astrocytomas** are actually the most common **benign** cerebellar tumor in children and represent a significant portion of all cerebellar tumors [1]. - However, in competitive exam contexts, when asking about "most common cerebellar tumor," the question typically refers to **malignant tumors**, where medulloblastoma takes precedence. - **Pilocytic astrocytomas** are usually low-grade (WHO Grade I) and have an excellent prognosis, often presenting as cystic lesions with a mural nodule. *Ependymoma* - **Ependymomas** are the third most common posterior fossa tumor in children (after medulloblastoma and pilocytic astrocytoma). - They typically arise from the ependymal lining of the **fourth ventricle**, making them cerebellar-adjacent rather than primarily cerebellar tumors [3], [4]. - They account for about 10% of pediatric brain tumors and have an intermediate prognosis. *PNET* - **PNET (Primitive Neuroectodermal Tumor)** is a historical term that has largely been replaced by more specific classifications in the current WHO CNS tumor classification. - Medulloblastoma was previously classified as a type of PNET, but is now recognized as a distinct entity. - The term PNET is now rarely used in modern neuropathology practice, having been superseded by molecular and genetic classification systems. **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. 1314-1315. [3] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Manifestations Of Central And Peripheral Nervous System Disease, pp. 726-727. [4] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Central Nervous System, pp. 1312-1313.

Question 3: A child presented to the casualty department with fever, unconsciousness, and papilledema. What is the next step?

A. Oxygenation
B. Intubation (Correct Answer)
C. CT scan
D. All of the options

Explanation: **Intubation** - The presence of **unconsciousness** indicates a compromised airway and breathing, making immediate **airway management** and **ventilatory support** a priority. - Papilledema, fever, and unconsciousness suggest increased **intracranial pressure** which can lead to brainstem herniation and respiratory arrest, necessitating **controlled ventilation** to reduce CO2 and ICP. *Oxygenation* - While **oxygenation** is critical, it is often insufficient alone in an unconscious patient with a compromised airway. - **Intubation** ensures a patent airway and delivers controlled oxygenation and ventilation more effectively than oxygenation via mask in this situation. *CT scan* - A **CT scan** is a diagnostic tool, but it should only be performed after the patient is **stabilized** hemodynamically and respiratory-wise. - Transporting an **unconscious** patient with potential increased ICP for a CT scan without securing the airway carries significant risks. *All of the options* - While all listed steps are important in managing a child with these symptoms, **intubation** (airway and breathing stabilization) is the **most immediate and critical next step**. - The sequence of medical interventions follows the **ABC (Airway, Breathing, Circulation)** protocol, making airway management the top priority before diagnostics or other treatments.

Question 4: Which of the following statements about astrocytoma is false?

A. Low grade tumors are more common in children
B. These are mostly infratentorial in children
C. Pilocytic astrocytoma is most common childhood brain tumor
D. They are more common in males than females (Correct Answer)

Explanation: ***They are more common in males than females*** - This statement is **false** because, while specific types of astrocytomas might show slight sex predominance, astrocytomas as a whole do not consistently show a significantly higher incidence in males compared to females. [1] - The incidence of astrocytomas is generally considered to be **roughly equal** between sexes or with only minor, inconsistent differences depending on the specific subtype and age group. *Low grade tumors are more common in children* - This statement is **true** because pediatric gliomas, including astrocytomas, are predominantly **low-grade (WHO grade I or II)**, accounting for about half of all central nervous system tumors in children. [2] - **Pilocytic astrocytoma (WHO grade I)** is a common example, known for its slow growth and often favorable prognosis. [2] *These are mostly infratentorial in children* - This statement is **true** as astrocytomas in children frequently occur in the **infratentorial region**, particularly the cerebellum, brainstem, and optic pathways. [1], [2] - This contrasts with adults, where supratentorial locations are more common; **cerebellar astrocytoma** is a classic example in children. [1] *Pilocytic astrocytoma is most common childhood brain tumor* - This statement is **true** as **pilocytic astrocytoma (WHO grade I)** is indeed the most common type of pediatric primary brain tumor, accounting for a significant proportion of all childhood CNS neoplasms. [2] - It often presents as a **cystic lesion with a mural nodule** and has a relatively good prognosis compared to higher-grade astrocytomas. **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 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: A 10 year old child presented with headache, vomiting, gait instability and diplopia. On examination he had papilledema and gait ataxia. The most probable diagnosis is –

A. Suprasellar tumour
B. Hydrocephalus
C. Brain stem tumour
D. Midline posterior fossa tumour (Correct Answer)

Explanation: ***Midline posterior fossa tumour*** - The combination of **headache, vomiting, papilledema (signs of increased intracranial pressure)**, **gait instability, and ataxia** strongly suggests a **midline posterior fossa tumor** in a child. These tumors often obstruct CSF flow, leading to hydrocephalus and cerebellar symptoms. - Common tumors in this location in children include **medulloblastoma** and **pilocytic astrocytoma**, which frequently present with these symptoms due to their proximity to the **fourth ventricle** and **cerebellum**. *Suprasellar tumour* - **Suprasellar tumors** typically present with **visual field deficits** (e.g., bitemporal hemianopia) due to compression of the optic chiasm, and/or **endocrine dysfunction** (e.g., growth delay, diabetes insipidus). - While they can cause hydrocephalus and increased intracranial pressure if large, the prominent **gait instability and ataxia** point away from a primary suprasellar lesion as the most likely cause. *Hydrocephalus* - **Hydrocephalus** itself explains the **increased intracranial pressure (headache, vomiting, papilledema)** and sometimes **gait instability (ataxia)**. - However, hydrocephalus is usually a *consequence* of an underlying obstruction, and in a child presenting acutely with cerebellar dysfunction, a **tumor blocking CSF flow in the posterior fossa** is the most probable underlying cause, not hydrocephalus as the primary diagnosis. *Brain stem tumour* - **Brain stem tumors** typically cause **cranial nerve deficits** (e.g., facial weakness, dysphagia), **long tract signs (hemiparesis)**, and often **multiple types of ataxia**, alongside signs of increased intracranial pressure if they obstruct CSF flow. - While gait instability and diplopia can occur, the overall picture of prominent **gait ataxia** and papilledema without other focal cranial nerve signs makes a primary midline posterior fossa tumor compressing the cerebellum and fourth ventricle more likely.

Question 7: Amount of ORS to be given in the first 4 hours to a child with some dehydration is

A. 75 ml/kg body wt. (Correct Answer)
B. 50 ml/kg body wt.
C. 100 ml/kg body wt.
D. 200 ml/kg body wt.

Explanation: ***75 ml/kg body wt.*** - For a child with **some dehydration**, the World Health Organization (WHO) and UNICEF recommend administering **75 mL/kg body weight** of ORS over the first 4 hours as part of Plan B. - This volume is calculated to replenish lost fluids and electrolytes, addressing the estimated fluid deficit in **some dehydration**. *50 ml/kg body wt.* - A dose of **50 mL/kg** is generally insufficient for effective rehydration in a child presenting with **some dehydration**. - This amount might be used in milder cases or for maintenance, but not for initial rehydration in the **first 4 hours** with signs of dehydration. *100 ml/kg body wt.* - Administering **100 mL/kg** body weight is typically used for **severe dehydration** (Plan C) when given as **intravenous fluids**. - For **some dehydration** treated with ORS, the recommended dose is 75 mL/kg, not 100 mL/kg. This higher amount could lead to fluid overload if given orally in the first 4 hours. *200 ml/kg body wt.* - A dose of **200 mL/kg** body weight is excessive and potentially dangerous for a child with **some dehydration**. - Such a large volume could lead to **fluid overload**, electrolyte imbalances, and other complications, especially in young children.

Question 8: A 2 year old child is seen on a routine visit in the pediatric clinic. Abdominal examination demonstrates a palpable, non-tender mass on the left side of the abdomen. The mother had no idea the mass was present and the pediatrician did not note the presence of the mass at the child's 18-month's visit for immunisation. Physical examination is otherwise unremarkable. If a CT guided biopsy of the mass were performed, which of the following histological patterns would be most suggestive of the likely diagnosis?

A. Triphasic pattern with tubule formation, spindle cells, and blastemal elements (Correct Answer)
B. Invasive papillary lesions with delicate connective tissue stalk covered with epithelium resembling that lining the bladder.
C. Cords of clear cells with rounded or polygonal shape and abundant clear cytoplasm
D. Small dark cells embedded in a finely fibrillar matrix with formation of numerous rosettes

Explanation: ***Triphasic pattern with tubule formation, spindle cells, and blastemal elements*** - The presence of a **palpable, non-tender abdominal mass** in a 2-year-old, previously undetected, is highly suggestive of **Wilms tumor (nephroblastoma)**. - Wilms tumor characteristically exhibits a **triphasic histological pattern** consisting of **blastemal**, **stromal (spindle cells)**, and **epithelial (tubule formation)** elements. *Invasive papillary lesions with delicate connective tissue stalk covered with epithelium resembling that lining the bladder.* - This description typically refers to **papillary urothelial carcinoma**, a tumor of the **bladder or urinary tract**, which is rarely seen in young children and presents with hematuria, not primarily an abdominal mass. - The absence of urinary symptoms and the age of the patient make this an unlikely diagnosis for an abdominal mass. *Cords of clear cells with rounded or polygonal shape and abundant clear cytoplasm* - This histological pattern is characteristic of **clear cell renal carcinoma**, an adult kidney malignancy, not a common pediatric abdominal tumor. - While clear cell renal cell carcinoma can present as an abdominal mass, it is exceptionally rare in a 2-year-old child. *Small dark cells embedded in a finely fibrillar matrix with formation of numerous rosettes* - This description is highly suggestive of **neuroblastoma**, a small round blue cell tumor that arises from neural crest cells (e.g., adrenal gland or sympathetic chain). - While **neuroblastoma** is the second most common abdominal mass in children after Wilms tumor, it typically presents with different histological features and may be associated with systemic symptoms like weight loss, fever, or bone pain. - The **triphasic pattern** described in option A is more specific for Wilms tumor.

Question 9: Which of the following is the most frequent primary malignant tumor of the CNS?

A. Glioblastoma multiforme (Correct Answer)
B. Oligodendroglioma
C. Medulloblastoma
D. Meningioma

Explanation: ***Glioblastoma multiforme*** - **Glioblastoma multiforme (GBM)** is the most common and aggressive primary malignant brain tumor in adults [1]. - It is a **grade IV astrocytoma**, characterized by rapid growth, necrosis, and microvascular proliferation [1]. *Oligodendroglioma* - **Oligodendrogliomas** are primary glial tumors but are less common than GBM. - They typically have a more indolent course than GBM and are often characterized by **IDH mutations** and **1p/19q co-deletion**. *Medulloblastoma* - **Medulloblastoma** is the most common malignant brain tumor in children, but it is rare in adults [2]. - It arises in the **cerebellum** and is a type of embryonal tumor [2]. *Meningioma* - **Meningiomas** are the most common primary brain tumors overall, but they are typically **benign** and originate from the meninges. - While they can be symptomatic due to compression, they are not primarily malignant in the way GBM is. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Central Nervous System, pp. 1308-1310. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Manifestations Of Central And Peripheral Nervous System Disease, pp. 725-726.

Question 10: A 7 – year old boy presented with abdominal pain, vomiting, oliguria, and periorbital puffiness following chemotherapy. Investigations reveal hyperuricemia, raised creatinine levels, and hyperkalemia. What is the next best step in the management of this condition ?

A. Hydration (Correct Answer)
B. Probenecid
C. Allopurinol
D. Rasburicase

Explanation: ***Hydration*** - This patient presents with **tumor lysis syndrome (TLS)**, characterized by rapid tumor cell breakdown releasing intracellular contents (uric acid, potassium, phosphate) following chemotherapy. - **Aggressive intravenous hydration** is the **first-line and most critical initial step** in TLS management, aiming to maintain urine output at 2-3 mL/kg/hour to prevent uric acid crystal precipitation in renal tubules. - Even with oliguria present, optimizing intravascular volume and renal perfusion is essential before other interventions can be effective - without adequate hydration, rasburicase-generated allantoin cannot be excreted. - **Hydration forms the foundation** upon which all other TLS therapies depend, making it the priority "next best step." *Probenecid* - **Probenecid** is a uricosuric agent that increases renal uric acid excretion by blocking tubular reabsorption. - It is **contraindicated in tumor lysis syndrome** as it increases uric acid concentration in renal tubules, potentially worsening uric acid nephropathy and crystal formation. *Allopurinol* - **Allopurinol** is a xanthine oxidase inhibitor that prevents new uric acid formation by blocking purine metabolism. - While valuable for **prophylaxis** in high-risk patients before chemotherapy, it **does not reduce existing hyperuricemia** in established TLS. - Less effective than rasburicase for treating active, symptomatic hyperuricemia. *Rasburicase* - **Rasburicase** is a recombinant urate oxidase that rapidly converts uric acid to allantoin (5-10 times more soluble). - Highly effective for **treating established hyperuricemia** in TLS and often used in severe cases. - However, as the "next best step," **hydration must be established first** to ensure adequate renal perfusion and allow excretion of metabolites - rasburicase is typically administered **after or concurrent with** hydration initiation. - In clinical practice, both are often started together, but hydration is the foundational intervention.

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