Neuropathology Practice Questions

Q: In the provided histopathology image of a schwannoma, what does the arrow-marked lesion represent?

Antoni A tissue with Verocay body. ***Antoni A tissue with Verocay body*** - **Antoni A tissue** is the densely cellular component of schwannoma with **spindle-shaped Schwann cells** arranged in compact fascicles. - **Verocay bodies** are pathognomonic features consisting of **nuclear palisading** around **acellular eosinophilic zones**, exclusively found in Antoni A areas. *Rosettes* - **Rosettes** are circular arrangements of cells around a central lumen, typically seen in **ependymomas** and other CNS tumors. - They are **not characteristic** of schwannomas and represent a different histological pattern entirely. *Antoni B tissue with Verocay body* - **Antoni B tissue** consists of **loose, myxoid, hypocellular areas** with scattered Schwann cells in a mucoid matrix. - **Verocay bodies are never found** in Antoni B tissue - they are **exclusive to Antoni A areas** only. *Palisading* - **Palisading** refers to the general arrangement of nuclei in parallel rows, seen in various tumors including **glioblastoma** and **fibrous histiocytoma**. - While palisading occurs in Verocay bodies, the **complete structure** (palisading nuclei + acellular eosinophilic center) defines the **Verocay body**, not just palisading alone.

Q: Which of the following conditions is characterized by cafe-au-lait spots, non-encapsulation, and potential for malignant transformation?

Neurofibroma. ### Explanation **Neurofibroma** is the correct answer because it fits the classic triad mentioned in the question: 1. **Association with Café-au-lait spots:** Multiple neurofibromas are a hallmark of Neurofibromatosis Type 1 (NF1/von Recklinghausen disease), which is characterized by $\geq 6$ café-au-lait macules. 2. **Non-encapsulated:** Unlike Schwannomas, neurofibromas are not encapsulated. They consist of a mixture of cell types (Schwann cells, fibroblasts, perineural cells) and an abundant myxoid matrix that infiltrates the nerve fascicles. 3. **Malignant Transformation:** While most are benign, plexiform neurofibromas have a significant risk (approx. 5–10%) of transforming into **Malignant Peripheral Nerve Sheath Tumors (MPNST)**. --- ### Analysis of Incorrect Options: * **A. Neurilemmoma (Schwannoma):** These are **encapsulated** tumors composed purely of Schwann cells. They do not typically transform into malignancy and are not the primary association for café-au-lait spots. * **C. Traumatic Neuroma:** This is a reactive proliferation of nerve fibers following injury, not a true neoplasm. It is often painful but lacks malignant potential and systemic associations like café-au-lait spots. * **D. Solitary Plasmacytoma:** This is a plasma cell neoplasm of the bone or soft tissue. It is unrelated to neural tumors or the cutaneous markers of neurofibromatosis. --- ### High-Yield Clinical Pearls for NEET-PG: * **Button-hole sign:** Pathognomonic for neurofibromas (the tumor can be pushed back into the dermis with a finger). * **Crowe’s Sign:** Axillary or inguinal freckling (another major diagnostic criterion for NF1). * **Lisch Nodules:** Hamartomas of the iris seen in NF1. * **Histology:** Neurofibromas show a "shredded carrot" appearance of collagen bundles.

Q: A 70-year-old male patient presented with forgetfulness of keys and difficulty performing household chores. The patient has trouble driving and takes longer to recognize family members' faces. On examination, the Mini-Mental State Examination (MMSE) score was 20/30. Consciousness was intact, and no focal neurological deficits were present. A Bielschowsky stain revealed characteristic findings. Which anatomical region typically shows the earliest pathological changes in this condition?

Hippocampus. **Explanation:** The clinical presentation of progressive memory loss, executive dysfunction (difficulty with chores), and prosopagnosia (difficulty recognizing faces) in an elderly patient with an MMSE score of 20/30 is classic for **Alzheimer’s Disease (AD)**. The mention of **Bielschowsky silver stain** is a high-yield histological clue, as it is used to visualize **Senile (Neuritic) Plaques** and **Neurofibrillary Tangles (NFTs)**, the pathological hallmarks of AD. **Why Hippocampus is Correct:** In Alzheimer’s Disease, the neurodegenerative process follows a predictable anatomical progression. The earliest pathological changes (NFTs) typically begin in the **entorhinal cortex**, followed rapidly by the **hippocampus** (part of the medial temporal lobe). This explains why episodic memory impairment is the earliest clinical symptom. **Analysis of Incorrect Options:** * **A. Mammillary body:** Atrophy of the mammillary bodies is a hallmark of **Wernicke-Korsakoff Syndrome** (due to Thiamine deficiency), not AD. * **B. Thalamus:** While involved in various dementias and metabolic encephalopathies, it is not the primary or earliest site of pathology in AD. * **D. Caudate nucleus:** Atrophy of the caudate nucleus is the characteristic finding in **Huntington’s Disease**, leading to boxcar ventricles on imaging. **NEET-PG High-Yield Pearls:** * **Pathology:** Extracellular Amyloid-beta plaques and Intracellular Tau protein (hyperphosphorylated) tangles. * **Genetics:** Early-onset AD is associated with APP (Chr 21), Presenilin 1 (Chr 14), and Presenilin 2 (Chr 1). Late-onset is associated with **ApoE4**. * **Neurochemistry:** Significant decrease in **Acetylcholine** levels due to degeneration of the **Nucleus Basalis of Meynert**. * **Imaging:** MRI shows bilateral hippocampal atrophy and compensatory ventriculomegaly.

Question 1

Which is the most common type of brain tumor?

Accepted Answer

Metastatic tumors (secondaries)

Answer

Medulloblastoma

Answer

Glioblastoma

Answer

Craniopharyngioma

Question 2

Which tumor has the best prognosis?

Accepted Answer

Cerebellar astrocytoma

Answer

Ependymoma

Answer

Medulloblastoma

Answer

Glioblastoma multiforme

Question 3

Which of the following structures is most prone to hypoxic injury?

Accepted Answer

Hippocampus

Answer

Thalamus

Answer

Caudate nucleus

Answer

Cerebellum

Question 4

Elongated filaments in Pick's disease consist of?

Accepted Answer

Hyperphosphorylated tau

Answer

Ubiquitin

Answer

Alpha-synuclein

Answer

Beta-synuclein

Question 5

Which of the following is NOT a neoplasm that patients with neurofibromatosis are prone to develop?

Accepted Answer

Retinoblastoma

Answer

Gliomas

Answer

Schwannoma

Answer

Meningioma

Question 6

Onion bulb appearance on nerve biopsy is seen in which of the following conditions?

Accepted Answer

Chronic inflammatory demyelinating polyneuropathy (CIDP)

Answer

Amyloid neuropathy

Answer

Diabetic neuropathy

Answer

Leprous neuritis

Question 7

In the provided histopathology image of a schwannoma, what does the arrow-marked lesion represent?

Accepted Answer

Antoni A tissue with Verocay body

Answer

Rosettes

Answer

Antoni B tissue with Verocay body

Answer

Palisading

Question 8

Which of the following conditions is characterized by cafe-au-lait spots, non-encapsulation, and potential for malignant transformation?

Accepted Answer

Neurofibroma

Answer

Neurilemmoma

Answer

Traumatic Neuroma

Answer

Solitary plasmocytoma

Question 9

A 20-year-old man presents with numerous pigmented patches and pedunculated skin tumors. Biopsy of a tumor reveals a benign neoplasm of Schwann cells. The patient has no family history of this condition. The patient is at increased risk of developing which of the following malignant neoplasms?

Accepted Answer

Neurofibrosarcoma

Answer

Ganglioneuroma

Answer

Glioblastoma multiforme

Answer

Serous cystadenocarcinoma

Question 10

A 70-year-old male patient presented with forgetfulness of keys and difficulty performing household chores. The patient has trouble driving and takes longer to recognize family members' faces. On examination, the Mini-Mental State Examination (MMSE) score was 20/30. Consciousness was intact, and no focal neurological deficits were present. A Bielschowsky stain revealed characteristic findings. Which anatomical region typically shows the earliest pathological changes in this condition?

Accepted Answer

Hippocampus

Answer

Mammillary body

Answer

Thalamus

Answer

Caudate nucleus

Neuropathology — MCQs

Neuropathology — MCQs

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