Neuropathology Practice Questions

Q: What is the most common intracranial tumor?

Metastatic tumors. **Explanation:** **Correct Answer: A. Metastatic tumors** In adults, **metastatic tumors** are the most common intracranial neoplasms, accounting for approximately 50% of all brain tumors [1]. They typically reach the brain via hematogenous spread and are often found at the grey-white matter junction. The most common primary sources are the **Lung (most common overall)**, Breast, Skin (Melanoma), Kidney (RCC), and Colon [1]. **Why the other options are incorrect:** * **B. Neuroblastoma:** This is a common extracranial solid tumor in children, usually arising from the adrenal medulla or sympathetic chain. While it can metastasize to the skull (causing "raccoon eyes"), it is not a primary or the most common intracranial tumor. * **C. Schwannoma:** These are benign tumors of the peripheral nerves (most commonly CN VIII). While common among nerve sheath tumors, they represent only about 8% of intracranial neoplasms. * **D. Ependymoma:** These are primary glial tumors arising from the lining of the ventricles. They are more common in children (typically in the 4th ventricle) but are far less frequent than metastases or astrocytomas. **High-Yield Clinical Pearls for NEET-PG:** * **Most common primary CNS tumor in adults:** Glioblastoma Multiforme (GBM). * **Most common primary CNS tumor in children:** Pilocytic Astrocytoma (followed by Medulloblastoma) [1]. * **Most common site for brain metastasis:** The distribution follows blood flow; hence, the **Cerebrum (80%)** is the most common site, followed by the Cerebellum. * **Radiology:** Metastases typically appear as multiple, well-circumscribed, ring-enhancing lesions with significant peritumoral edema. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Central Nervous System, pp. 1317-1320.

Q: What is chromatolysis?

Disappearance of Nissl granules. **Explanation:** **Chromatolysis** is a reactive change seen in the cell body (perikaryon) of a neuron in response to axonal injury (axonal reaction) [1]. It represents a regenerative effort by the cell to increase protein synthesis for axonal repair [1]. 1. **Why Option C is Correct:** The hallmark of chromatolysis is the **disappearance or dispersion of Nissl granules** (which are clusters of Rough Endoplasmic Reticulum and free ribosomes) [1]. Under light microscopy, the cytoplasm appears pale and homogeneous because the basophilic staining of the Nissl substance is lost as it undergoes dissolution and moves toward the periphery. 2. **Why Other Options are Incorrect:** * **A. Disintegration of the nucleus:** In chromatolysis, the nucleus does not disintegrate; instead, it typically becomes **eccentric** (pushed to the periphery) and the nucleolus becomes prominent [1]. * **B. Disintegration of the Golgi apparatus:** While the Golgi may undergo structural changes during cellular stress, it is not the defining feature of chromatolysis. * **D. Decrease in cell size:** Chromatolysis is characterized by **cellular swelling** (increased size) and a rounded contour, not a decrease in size [1]. **NEET-PG High-Yield Pearls:** * **Key Morphological Triad:** 1. Dissolution of Nissl bodies (Chromatolysis), 2. Displacement of the nucleus to the periphery, 3. Swelling of the cell body [1]. * **Significance:** It is a sign of **axonal reaction** (retrograde change) following trauma or axotomy [1]. * **Wallerian Degeneration:** This refers to the changes occurring *distal* to the site of axonal injury, whereas chromatolysis occurs in the *cell body*. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Peripheral Nerves and Skeletal Muscles, pp. 1254-1255.

Q: What is the most common tumor in the lateral hemisphere of the brain?

Astrocytoma. **Explanation:** **Astrocytomas** are the most common primary intra-axial tumors of the central nervous system [1]. In adults, these tumors predominantly occur in the cerebral hemispheres (lateral hemispheres) [1]. They belong to the group of gliomas and range from low-grade (pilocytic astrocytoma) to the highly malignant Glioblastoma Multiforme (GBM), which is the most frequent primary brain malignancy in adults. **Analysis of Options:** * **Meningioma (Option B):** While these are the most common *overall* primary intracranial tumors, they are **extra-axial** (arising from the arachnoid cap cells of the meninges) rather than tumors *in* the brain parenchyma itself. * **Ependymoma (Option C):** These typically arise from the lining of the ventricular system. In children, they are most common in the fourth ventricle (posterior fossa), whereas in adults, they are more frequently found in the spinal cord. * **Medulloblastoma (Option D):** This is a highly malignant embryonal tumor (PNET) that occurs almost exclusively in the **cerebellum** (posterior fossa) of children [1]. It does not typically occur in the lateral cerebral hemispheres. **NEET-PG High-Yield Pearls:** * **Most common primary brain tumor (Overall):** Meningioma. * **Most common primary intra-axial brain tumor:** Astrocytoma (specifically GBM). * **Most common brain tumor (General):** Metastasis (usually multiple, at the grey-white matter junction). * **Rosenthal fibers:** Characteristic of Pilocytic Astrocytoma (Grade I). * **Butterfly Glioma:** Refers to GBM crossing the corpus callosum. **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.

Question 1

What is the characteristic pathological manifestation in rabies?

Accepted Answer

Brainstem encephalitis

Answer

Ventriculitis

Answer

Basal ganglia affection

Answer

Meningitis

Question 2

The morphologic features of neuronal cell death consist of all EXCEPT:

Accepted Answer

Basophilic inclusions

Answer

Shrinkage of cell body

Answer

Disappearance of Nissl's substance

Answer

Pyknosis of the nucleus

Question 3

A WHO grade I tumour is located in the cerebellum. On histological examination, Rosenthal fibres are seen. What is the most probable diagnosis?

Accepted Answer

Pilocytic astrocytoma

Answer

Medulloblastoma

Answer

Craniopharyngioma

Answer

Ependymoma

Question 4

What is the most common intracranial tumor?

Accepted Answer

Metastatic tumors

Answer

Neuroblastoma

Answer

Schwannoma

Answer

Ependymoma

Question 5

All of the following are true about Medulloblastoma except?

Accepted Answer

It arises from the cerebellum

Answer

It is a small round blue cell tumor

Answer

It is an embryonal tumor

Answer

Chang staging system is used

Question 6

What is chromatolysis?

Accepted Answer

Disappearance of Nissl granules

Answer

Disintegration of the nucleus

Answer

Disintegration of the Golgi apparatus

Answer

Decrease in cell size

Question 7

Which of the following intracranial tumors has the best prognosis?

Accepted Answer

Cerebellar astrocytoma

Answer

Glioblastoma

Answer

Medulloblastoma

Answer

Ependymoma

Question 8

Which protein is primarily involved in Alzheimer's disease?

Accepted Answer

All of the above

Answer

Apolipoprotein E gene

Answer

Presenilin II

Answer

Amyloid precursor protein

Question 9

Ependymomas are commonly associated with which of the following conditions?

Accepted Answer

Neurofibromatosis 2

Answer

Tuberous sclerosis

Answer

Neurofibromatosis 1

Answer

All of the above

Question 10

What is the most common tumor in the lateral hemisphere of the brain?

Accepted Answer

Astrocytoma

Answer

Meningioma

Answer

Ependymoma

Answer

Medulloblastoma

Neuropathology — MCQs

Neuropathology — MCQs

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