Neuropathology Practice Questions

Q: Which of the following is not seen after nerve transection?

Neuroma in continuity. ***Neuroma in continuity*** - A **neuroma in continuity** occurs when a nerve is injured but remains anatomically intact, meaning there is still some *continuity* of the nerve fibers, albeit scarred or dysfunctional. - In a true **nerve transection**, the nerve is completely severed, making a neuroma in continuity impossible as the nerve ends are no longer connected. *Myelin ovoids* - **Myelin ovoids** are characteristic globular remnants of degraded myelin sheath that form in the distal segment of a transected nerve following **Wallerian degeneration** [2]. - They are a normal and expected finding after nerve transection as the axon and myelin distal to the injury degenerate. *Painful neuroma* - A **painful neuroma**, also known as a stump neuroma, can form at the *proximal* end of a transected nerve [1]. - This occurs due to disorganized growth of regenerating nerve fibers into scar tissue, leading to a tangled mass that can be exquisitely sensitive and painful [1]. *Morphologic pattern of Wallerian degeneration* - **Wallerian degeneration** is the *entire process* of axonal and myelin sheath degeneration that occurs in the distal segment of a nerve fiber after it has been severed from its cell body [2]. - This *morphologic pattern* is the primary response of the distal nerve segment to transection, involving breakdown and phagocytosis of debris [2]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Peripheral Nerves and Skeletal Muscles, p. 1232. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Manifestations Of Central And Peripheral Nervous System Disease, pp. 697-698.

Q: Which of the following statements about the pathology in Alzheimer's disease is false?

NFTs appear extracellularly before intracellular appearance. ***NFTs appear extracellularly before intracellular appearance*** - This statement is **false** because **neurofibrillary tangles (NFTs)** are **intracellular accumulations** of hyperphosphorylated tau protein [3]. - They develop within neurons before the cell degenerates and releases the tangles into the extracellular space [1], [4]. *Neuritic Plaques are formed of amyloid protein* - **Neuritic plaques** (also known as **amyloid plaques**) are correctly described as being composed primarily of aggregated **amyloid-beta (Aβ) protein** [3]. - These plaques are extracellular deposits found in the brain parenchyma in Alzheimer's disease. *Number of NFTs correlates with dementia* - The **density and distribution of neurofibrillary tangles (NFTs)** in the brain are strongly correlated with the severity of **cognitive decline and dementia** in Alzheimer's disease [2]. - Unlike amyloid plaques, NFTs are considered a better indicator of the clinical progression of the disease [2]. *Neurofibrillary tangles (NFT) are made of tau protein* - **Neurofibrillary tangles (NFTs)** are indeed hallmark lesions in Alzheimer's disease composed of hyperphosphorylated and aggregated strands of **tau protein** [1], [3]. - Tau protein typically stabilizes microtubules within neurons, but in AD, it detaches and forms insoluble aggregates. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Central Nervous System, pp. 1292-1293. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Central Nervous System, p. 1292. [3] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Manifestations Of Central And Peripheral Nervous System Disease, pp. 721-722. [4] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Central Nervous System, pp. 1292-1294.

Q: Which of the following markers is most commonly associated with neuroblastoma?

Chromogranin A. ***Chromogranin A*** - **Chromogranin A** is a common **neuroendocrine marker** and is often elevated in neuroblastoma, a neuroendocrine tumor. - Its levels can be used for **diagnosis** and **monitoring treatment response** in patients with neuroblastoma. *NMP 22* - **NMP22 (Nuclear Matrix Protein 22)** is a marker primarily used for the **detection and surveillance of bladder cancer**. - It is not typically associated with neuroblastoma. *LDH* - **LDH (Lactate Dehydrogenase)** is a general marker of **tissue damage or high tumor burden**. [1] - While LDH can be elevated in neuroblastoma due to rapid tumor growth, it is **non-specific** and not the most commonly associated specific marker for this cancer. *β2 microglobulin* - **β2 microglobulin** is a protein found on the surface of most nucleated cells and is elevated in conditions such as **lymphomas**, **multiple myeloma**, and **renal dysfunction**. - It is not considered a primary or specific marker for neuroblastoma. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of Infancy and Childhood, p. 486.

Q: Which disease is characterized by protein misfolding and aggregation, particularly involving alpha-synuclein?

Parkinson's disease. ***Parkinson's disease*** - It is characterized by the accumulation of misfolded **alpha-synuclein** protein, forming **Lewy bodies** in neurons [1]. - This protein aggregation leads to neuronal dysfunction and death, particularly in the **substantia nigra**, affecting dopamine production [1]. *Marfan syndrome* - This is a **genetic disorder** affecting connective tissue, caused by mutations in the **FBN1 gene**, which encodes for fibrillin-1. - It does not involve protein misfolding or aggregation of alpha-synuclein but rather structural defects in connective tissues [2]. *Acute intermittent porphyria* - This is a metabolic disorder resulting from a deficiency in **hydroxymethylbilane synthase**, an enzyme in the heme synthesis pathway. - It leads to the accumulation of **porphyrin precursors** like delta-aminolevulinic acid and porphobilinogen, causing neurovisceral attacks. *Wermer syndrome* - This is an older term for **Multiple Endocrine Neoplasia type 1 (MEN1)**, a genetic condition causing tumors in multiple endocrine glands. - It is due to mutations in the **MEN1 gene**, which encodes for menin, and does not involve alpha-synuclein misfolding or aggregation.

Q: What is the most common site for berry aneurysm rupture?

Anterior circulation of brain. **Anterior circulation of brain** - The **anterior circulation** of the brain, predominantly the **Circle of Willis**, is the most common location for **berry aneurysms**, particularly at arterial bifurcations [4]. - Rupture in this location often leads to **subarachnoid hemorrhage**, causing sudden severe headache, meningismus, and neurological deficits [1], [2]. *Posterior circulation of brain* - While aneurysms can occur in the **posterior circulation** (vertebrobasilar system), they are significantly less common than in the anterior circulation. - Ruptures here may present with brainstem symptoms in addition to typical hemorrhage signs. *Ascending aorta* - Aneurysms of the **ascending aorta** are typically **fusiform** or **saccular** and are associated with connective tissue disorders or atherosclerosis rather than congenital berry aneurysms [3]. - Rupture of an ascending aortic aneurysm causes **aortic dissection** or contained rupture into the pericardium, leading to severe chest pain and cardiovascular collapse. *Descending aorta* - Aneurysms in the **descending aorta** are usually **atherosclerotic** in origin and are often detected incidentally [3]. - Rupture typically presents as severe back or abdominal pain and can lead to massive retroperitoneal hemorrhage.

Q: Rupture of berry aneurysm most commonly results in

Subarachnoid hemorrhage. ***Subarachnoid hemorrhage*** - **Berry aneurysms** are typically located in the **Circle of Willis**, often at arterial bifurcations. [1] - Their rupture leads to bleeding into the **subarachnoid space**, causing severe headache, nuchal rigidity, and altered mental status. [3] *Subdural hemorrhage* - This typically results from the tearing of **bridging veins** between the brain's surface and the dura mater. - It's often associated with trauma, especially in elderly individuals or those on anticoagulants, and not primarily with berry aneurysm rupture. [1] *Extradural hemorrhage* - Also known as **epidural hemorrhage**, it usually results from a traumatic arterial tear, most commonly involving the **middle meningeal artery**. [2], [4] - Blood accumulates between the dura mater and the skull, typically presenting with a lucid interval followed by rapid neurological deterioration. [4] *Intra-parenchymal hemorrhage* - This refers to bleeding within the brain tissue itself and is most commonly caused by **hypertension** leading to rupture of small vessels. [1] - While some aneurysms can rupture into the brain parenchyma, a rupture of a berry aneurysm primarily causes a subarachnoid hemorrhage. [1]

Q: Which of the following is most likely to be seen due to the rupture of a saccular aneurysm?

Subarachnoid hemorrhage. ***Subarachnoid hemorrhage*** - A **saccular aneurysm** (often a **berry aneurysm**) commonly ruptures into the **subarachnoid space**, causing bleeding around the brain [2]. - This leads to a sudden onset of a "thunderclap headache," **meningeal irritation**, and neurological deficits [1]. *Subdural hemorrhage* - A **subdural hemorrhage** is typically caused by the tearing of **bridging veins** between the dura and arachnoid mater, often due to **trauma** [3]. - While it can occur, it is a less common direct consequence of saccular aneurysm rupture compared to subarachnoid hemorrhage. *Intracerebral hemorrhage* - An **intracerebral hemorrhage** involves bleeding directly into the brain parenchyma, most often due to **hypertension** or **amyloid angiopathy**. - Although a ruptured aneurysm can rarely extend into the brain tissue, the primary initial bleeding is usually into the subarachnspace [4]. *Hydrocephalus* - **Hydrocephalus** can be a *complication* of a subarachnoid hemorrhage, resulting from impaired CSF reabsorption or obstruction of CSF flow due to blood clots. - However, it is not the *initial event* caused directly by the rupture of a saccular aneurysm [4].

Q: A 20-year-old man presented with a complaint of a swelling of the wrist for the last two years. Histopathological examination showed spindle-shaped cells and Verocay bodies. What is the diagnosis?

Schwannoma. ***Schwannoma*** - Characterized by the presence of **spindle-shaped cells** and **Verocay bodies**, typical of schwannomas, which are tumors of peripheral nerve sheath origin [1,3]. - Commonly presents with **pain** and **local swelling** in affected areas, aligning with the patient's symptoms [2]. *Dermoid cyst* - Usually presents as a **cystic lesion** containing skin appendages but does not feature spindle-shaped cells. - Lacks the characteristic **Verocay bodies**, which help differentiate schwannomas [1]. *Lipoma* - Composed of **mature adipocytes**, presenting as soft, movable masses, but not associated with spindle-shaped cells. - Histopathological examination would not reveal **Verocay bodies**, making it distinct from schwannoma [1]. *Neurofibroma* - Typically associated with **plexiform growth patterns** and lacks the classic **Verocay bodies** seen in schwannomas [1]. - Often occurs in patients with **neurofibromatosis** and presents differently than the clinical scenario here [3]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Peripheral Nerves and Skeletal Muscles, p. 1250. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Manifestations Of Central And Peripheral Nervous System Disease, pp. 727-728. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Peripheral Nerves and Skeletal Muscles, pp. 1248-1249.

Q: Which receptors are blocked in Myasthenia Gravis?

ACh receptors. ***Ach receptors*** - Myasthenia Gravis is an **autoimmune disease** where **antibodies** block, alter, or destroy the **nicotinic acetylcholine receptors** at the **neuromuscular junction** [1], [2]. - This blockage prevents **acetylcholine** from binding to the receptors, leading to impaired muscle contraction and **muscle weakness** [1]. *Ca++ receptors* - **Calcium channels** (not "receptors" in this context) are involved in the release of **acetylcholine** from the presynaptic terminal, but they are not the primary target in Myasthenia Gravis [1]. - While calcium influx is crucial for neurotransmitter release, the problem in Myasthenia Gravis lies postsynaptically, at the **acetylcholine receptor** [2]. *Na+ receptors* - **Sodium channels** are essential for generating and propagating **action potentials** in muscle fibers after acetylcholine binds and opens the acetylcholine receptor. - They are not directly targeted by autoantibodies in Myasthenia Gravis; the issue occurs upstream, preventing the initial depolarization signal [2]. *Opioid receptors* - **Opioid receptors** are involved in pain modulation and other central nervous system functions, primarily binding endorphins and exogenous opioids. - They have no role in the pathophysiology of Myasthenia Gravis, which is a disorder of the **neuromuscular junction** [2]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of the Immune System, pp. 213-214. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Peripheral Nerves and Skeletal Muscles, pp. 1237-1239.

Question 1

Which of the following is not seen after nerve transection?

Accepted Answer

Neuroma in continuity

Answer

Myelin ovoids

Answer

Painful neuroma

Answer

Morphologic pattern of Wallerian degeneration

Question 2

What is the primary pathophysiological mechanism of Lambert-Eaton syndrome?

Accepted Answer

IgG antibodies against voltage-gated calcium channels.

Answer

With continuous stimulation, there is a marked decrease in the amplitude of action potentials.

Answer

There is an increase in the release of presynaptic acetylcholine.

Answer

IgG antibodies against postsynaptic acetylcholine receptors.

Question 3

Which of the following statements about the pathology in Alzheimer's disease is false?

Accepted Answer

NFTs appear extracellularly before intracellular appearance

Answer

Neuritic Plaques are formed of amyloid protein

Answer

Number of NFTs correlates with dementia

Answer

Neurofibrillary tangles (NFT) are made of tau protein

Question 4

Which of the following markers is most commonly associated with neuroblastoma?

Accepted Answer

Chromogranin A

Answer

NMP 22

Answer

LDH

Answer

β2 microglobulin

Question 5

Which disease is characterized by protein misfolding and aggregation, particularly involving alpha-synuclein?

Accepted Answer

Parkinson's disease

Answer

Marfan syndrome

Answer

Acute intermittent porphyria

Answer

Wermer syndrome

Question 6

What is the most common site for berry aneurysm rupture?

Accepted Answer

Anterior circulation of brain

Answer

Posterior circulation of brain

Answer

Ascending aorta

Answer

Descending aorta

Question 7

Rupture of berry aneurysm most commonly results in

Accepted Answer

Subarachnoid hemorrhage

Answer

Subdural hemorrhage

Answer

Extradural hemorrhage

Answer

Intra-parenchymal hemorrhage

Question 8

Which of the following is most likely to be seen due to the rupture of a saccular aneurysm?

Accepted Answer

Subarachnoid hemorrhage

Answer

Subdural hemorrhage

Answer

Intracerebral hemorrhage

Answer

Hydrocephalus

Question 9

A 20-year-old man presented with a complaint of a swelling of the wrist for the last two years. Histopathological examination showed spindle-shaped cells and Verocay bodies. What is the diagnosis?

Accepted Answer

Schwannoma

Answer

Lipoma

Answer

Dermoid cyst

Answer

Neurofibroma

Question 10

Which receptors are blocked in Myasthenia Gravis?

Accepted Answer

ACh receptors

Answer

Opioid receptors

Answer

Na+ receptors

Answer

Ca++ receptors

Neuropathology — MCQs

Neuropathology — MCQs

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