Neuropathology Practice Questions

Q: A retraction ball is seen after injury to which organ?

Brain. **Explanation:** **Retraction balls** (also known as axonal bulbs) are the hallmark histopathological feature of **Diffuse Axonal Injury (DAI)** in the **Brain**. [1] 1. **Why Brain is Correct:** When the brain undergoes sudden acceleration or deceleration (as seen in motor vehicle accidents or falls), shearing forces act on the long white matter tracts. This mechanical stress causes the stretching and tearing of axons. The damage disrupts the normal axoplasmic flow; proteins and organelles transported from the cell body begin to accumulate at the site of the break. This leads to the focal swelling of the proximal axonal stump, which appears microscopically as an eosinophilic, rounded, or club-shaped structure called a **retraction ball**. These are best visualized using **Silver stains** or **Beta-Amyloid Precursor Protein (̢̢β-APP)** immunohistochemistry. 2. **Why Incorrect Options are Wrong:** * **Liver, Spleen, and Kidney:** These are solid visceral organs. Injury to these organs typically results in hemorrhage, infarction, or laceration. They do not contain long, myelinated axonal processes that exhibit the specific physiological "retraction" and swelling seen in neural tissue. **NEET-PG High-Yield Pearls:** * **DAI Locations:** Most commonly involves the **Corpus Callosum** and the **Dorsolateral Pons**. [1] * **Clinical Correlation:** DAI is a frequent cause of persistent vegetative state or immediate post-traumatic coma despite a normal initial CT scan. * **Staining:** While H&E shows them after 24–48 hours, **β-APP staining** can detect axonal damage as early as 2–3 hours post-injury. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Central Nervous System, pp. 1261-1264.

Q: All of the following are true about the microscopic appearance of pilocytic astrocytoma, EXCEPT:

Decrease in the number of blood vessels. ### Explanation **Pilocytic Astrocytoma (WHO Grade 1)** is the most common primary brain tumor in children, typically occurring in the cerebellum. **Why Option D is the Correct Answer:** Contrary to the option, Pilocytic Astrocytoma is characterized by **prominent vascularity**. It often exhibits **vascular endothelial proliferation** (glomeruloid bodies). While in other gliomas (like Glioblastoma) this indicates high-grade malignancy, in Pilocytic Astrocytoma, it is a benign feature and does not imply a poor prognosis. Therefore, a "decrease" in blood vessels is incorrect. **Analysis of Incorrect Options:** * **A. Bipolar cells:** These are the hallmark "piloid" (hair-like) cells. They are elongated cells with thin, hair-like bipolar processes, giving the tumor its name. * **B. Rosenthal fibers:** These are thick, elongated, eosinophilic, "corkscrew" shaped structures found within astrocytic processes. They represent degenerated intermediate filaments (ubiquitin and αB-crystallin). * **C. Eosinophilic granular bodies (EGBs):** These are small, proteinaceous droplets found in the tumor. Their presence is a classic marker of slow-growing, low-grade tumors. **NEET-PG High-Yield Pearls:** * **Biphasic Pattern:** Microscopic examination shows a mix of dense (Rosenthal fibers) and loose/microcystic (EGBs) areas. * **Genetics:** Strongly associated with **BRAF gene** alterations (KIAA1549-BRAF fusion). * **Imaging:** Classically presents as a **cystic lesion with an enhancing mural nodule** in the cerebellum. * **Prognosis:** Excellent; usually curable by surgical resection.

Question 1

In Alzheimer's disease, what is the characteristic pathological finding in the brain?

Accepted Answer

Atrophy of parietal and temporal lobes

Answer

Atrophy of temporal lobes

Answer

Atrophy of temporal and occipital lobes

Answer

Atrophy of parietal and occipital lobes

Question 2

A retraction ball is seen after injury to which organ?

Accepted Answer

Brain

Answer

Liver

Answer

Spleen

Answer

Kidney

Question 3

Neurofibrillary tangles with senile plaques are seen in which of the following conditions?

Accepted Answer

Alzheimer's disease

Answer

Parkinson's disease

Answer

Schizophrenia

Answer

Tuberous sclerosis

Question 4

Laminar necrosis and watershed infarcts are most suggestive of which of the following conditions?

Accepted Answer

Shock

Answer

Hypertension

Answer

Fat emboli

Answer

Vascular thrombosis

Question 5

What are the pathological lesions in the CNS in rabies?

Accepted Answer

Brainstem encephalitis

Answer

Cranial nerve arteritis

Answer

Neuronal loss

Answer

Neurofibrillary tangles

Question 6

Which type of herniation leads to brain stem injury?

Accepted Answer

Cerebellar tonsils

Answer

Cingulate

Answer

Hippocampal

Answer

Subfalcine

Question 7

Neuronophagia is seen in which of the following conditions?

Accepted Answer

Poliomyelitis

Answer

Amoebic encephalitis

Answer

Tuberculer meningoencephalitis

Answer

Cerebral malaria

Question 8

A 50-year-old woman undergoes neurosurgery for resection of a well-circumscribed intracranial neoplasm attached to the dura. The tumor compressed the underlying brain parenchyma without infiltration. Which of the following is the most likely diagnosis?

Accepted Answer

Meningioma

Answer

Arteriovenous malformation

Answer

Glioblastoma multiforme

Answer

Medulloblastoma

Question 9

All of the following are true about the microscopic appearance of pilocytic astrocytoma, EXCEPT:

Accepted Answer

Decrease in the number of blood vessels

Answer

Bipolar cells

Answer

Rosenthal fibers

Answer

Eosinophilic granular bodies

Question 10

All of the following are true about meningiomas EXCEPT:

Accepted Answer

They are attached to the pia mater.

Answer

Meningiomas are predominantly benign tumors of adults.

Answer

They arise from the meningothelial cell of the arachnoid.

Answer

They occur in association with eighth nerve schwannomas.

Neuropathology — MCQs

Neuropathology — MCQs

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