Neuropathology Practice Questions

Q: A 50-year-old man presents with a staggering gait and lightning pain in his hands and legs. His past medical history is significant for an aortic aneurysm and aortic insufficiency. Neurologic examination reveals impaired senses of vibration, as well as touch and pain in the lower extremities. The patient subsequently dies of pneumonia. Autopsy discloses obliterative endarteritis of meningeal blood vessels and atrophy of the posterior columns of the spinal cord. What is the appropriate diagnosis?

Tabes dorsalis. ### Explanation **Correct Answer: D. Tabes dorsalis** The clinical presentation and autopsy findings are classic for **Tertiary Syphilis**, specifically **Tabes dorsalis** (neurosyphilis) and **Syphilitic Aortitis**. 1. **Clinical Features:** "Lightning pains" (sharp, stabbing pains in the limbs) and a "staggering gait" (sensory ataxia due to loss of proprioception) are hallmark symptoms. 2. **Neurological Findings:** Impaired vibration and position sense indicate involvement of the **dorsal (posterior) columns** [1]. 3. **Pathology:** The autopsy finding of **obliterative endarteritis** (specifically *vasa vasorum* of the aorta leading to aneurysms/insufficiency) and **atrophy of the posterior columns** confirms the diagnosis. --- ### Why Other Options are Incorrect: * **A. Amyotrophic Lateral Sclerosis (ALS):** Involves both Upper and Lower Motor Neurons. It presents with muscle weakness and spasticity, but **sensory perception remains intact** [2]. * **B. Friedreich Ataxia:** While it involves the posterior columns and causes ataxia, it typically presents in **childhood/adolescence** and is associated with hypertrophic cardiomyopathy and kyphoscoliosis, not aortic aneurysms. * **C. Huntington Disease:** A trinucleotide repeat disorder characterized by **chorea** and progressive dementia due to atrophy of the **caudate nucleus**, not spinal cord atrophy. --- ### NEET-PG High-Yield Pearls: * **Argyll Robertson Pupil:** Often seen in Tabes dorsalis; pupils accommodate but do not react to light ("Prostitute's Pupil"). * **Romberg Sign:** Positive in Tabes dorsalis due to sensory ataxia (loss of proprioception) [3]. * **Charcot Joints:** Neuropathic arthropathy (painless joint destruction) is a common complication due to loss of pain sensation. * **Pathognomonic Pathology:** Look for "Heubner’s endarteritis" and "Gummas" in neurosyphilis questions.

Q: Which of the following gene is associated with Alzheimer's disease?

APOE4. Alzheimer’s Disease (AD) is the most common cause of dementia [1]. Its genetics are divided into early-onset (familial) and late-onset (sporadic) forms. The **APOE (Apolipoprotein E)** gene, located on chromosome 19, is the most significant genetic risk factor for late-onset AD. **Why APOE4 is correct:** The APOE gene has three common alleles: ε2, ε3, and ε4. The **APOE ε4 (APOE4)** allele increases the risk of developing AD and is associated with an earlier age of onset. It impairs the clearance of amyloid-beta (Aβ) peptides, leading to the formation of neuritic plaques, a hallmark of the disease. Inheriting one copy of ε4 increases risk 3-fold, while two copies increase risk 12-fold. **Analysis of Incorrect Options:** * **APOE1:** This is not a recognized common isoform of the Apolipoprotein E gene in human populations. * **APOE:** While this is the name of the gene itself, the question asks for the specific variant associated with the disease. * **APOE3:** This is the most common (neutral) allele. It is considered "risk-neutral" and does not significantly increase or decrease the risk of AD. **High-Yield Clinical Pearls for NEET-PG:** * **Protective Allele:** **APOE ε2** is considered protective against Alzheimer's disease. * **Early-Onset AD (Familial):** Associated with mutations in **APP** (Chr 21), **Presenilin 1** (Chr 14 - most common), and **Presenilin 2** (Chr 1). * **Down Syndrome Connection:** Patients with Trisomy 21 have an extra copy of the APP gene, leading to early-onset AD (often by age 40). * **Pathology:** Characterized by extracellular **Amyloid plaques** and intracellular **Neurofibrillary tangles** (composed of hyperphosphorylated **Tau protein**).

Q: Identify the rosette and its corresponding diagnosis.

Perivascular pseudorosette. ***Perivascular pseudorosette*** - Characterized by **radial arrangement** of tumor cells around blood vessels with **fibrillary processes** extending toward the vessel wall, creating a perivascular pattern. - **Pathognomonic** for **ependymoma**, a glial tumor arising from ependymal cells lining the ventricles and central canal of the spinal cord. *Homer Wright rosette* - Features tumor cells arranged in a **circular pattern** around a **central tangle of neural filaments** without a true lumen. - Classically associated with **neuroblastoma** and **medulloepithelioma**, but not diagnostic as they can be seen in other neural tumors. *True rosette* - Contains a **central true lumen** lined by tumor cells, representing primitive neural tube formation. - Seen in **primitive neuroectodermal tumors (PNET)** and **medulloepithelioma**, but less specific than other rosette types. *Flexner Wintersteiner rosette* - Shows tumor cells arranged around a **central lumen** with terminal bars and **internal limiting membrane**, resembling retinal photoreceptors. - **Pathognomonic** for **retinoblastoma**, the most common primary intraocular malignancy in children.

Q: Which chromosome mutation is associated with medulloblastoma?

Chromosome 17. **Explanation:** **Medulloblastoma** is the most common malignant brain tumor in children, typically arising in the cerebellum. The most characteristic cytogenetic abnormality associated with this tumor is **Isochromosome 17q (i17q)**. This mutation involves the loss of the short arm (17p) and the duplication of the long arm (17q). The loss of 17p is significant because it houses the **TP53** tumor suppressor gene (though TP53 mutations are specifically linked to the SHH subgroup), and i17q is a hallmark of the Group 3 and Group 4 molecular subtypes of medulloblastoma, carrying a poorer prognosis. **Analysis of Incorrect Options:** * **Chromosome 16:** Mutations here are more commonly associated with renal pathologies (like ADPKD - PKD1) or certain leukemias, but not classically with medulloblastoma. * **Chromosome 18:** Trisomy 18 (Edwards Syndrome) is a multisystem genetic disorder. While it increases the risk of some tumors (like Wilms tumor), it is not the primary association for medulloblastoma. * **Chromosome 19:** Codeletion of 1p/19q is the diagnostic molecular marker for **Oligodendrogliomas**, not medulloblastoma. **High-Yield Clinical Pearls for NEET-PG:** * **Location:** Always arises in the **cerebellum** (vermis in children, hemispheres in adults). * **Histology:** Characterized by **Homer-Wright Rosettes** and "small round blue cells." * **Drop Metastasis:** It has a high propensity to spread via CSF to the spinal cord [2]. * **Molecular Subgroups:** WNT (best prognosis), SHH, Group 3 (worst prognosis), and Group 4. * **Genetic Syndromes:** Associated with **Turcot Syndrome** (APC gene) and **Gorlin Syndrome** (PTCH1 gene) [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Neoplasia, pp. 306-307. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Central Nervous System, pp. 1314-1315.

Question 1

Peripheral nerve sheath tumors include all of the following except:

Accepted Answer

Synovial sarcoma

Answer

Schwannoma

Answer

Neurofibroma

Answer

Malignant peripheral nerve sheath tumor (MPNST)

Question 2

Spongiform changes in astrocytic tumor with neuronal loss is seen in?

Accepted Answer

Prion disease

Answer

Alzheimer's disease

Answer

Parkinson's disease

Answer

Amyloidosis

Question 3

A 50-year-old man presents with a staggering gait and lightning pain in his hands and legs. His past medical history is significant for an aortic aneurysm and aortic insufficiency. Neurologic examination reveals impaired senses of vibration, as well as touch and pain in the lower extremities. The patient subsequently dies of pneumonia. Autopsy discloses obliterative endarteritis of meningeal blood vessels and atrophy of the posterior columns of the spinal cord. What is the appropriate diagnosis?

Accepted Answer

Tabes dorsalis

Answer

Amyotrophic lateral sclerosis

Answer

Friedreich ataxia

Answer

Huntington disease

Question 4

Which of the following gene is associated with Alzheimer's disease?

Accepted Answer

APOE4

Answer

APOE1

Answer

APOE

Answer

APOE3

Question 5

A neuropathologist is performing an autopsy on a 65-year-old man who had resting tremor, rigidity, and akinesia. Histologic sections of the substantia nigra reveal neurons containing round eosinophilic inclusions. Such inclusions most likely represent?

Accepted Answer

Lewy bodies

Answer

Granulovacuolar degeneration

Answer

Hirano bodies

Answer

Lafora bodies

Question 6

Genetic alteration in which of the following chromosomes can lead to oligodendroglioma?

Accepted Answer

Chromosome 19q

Answer

Chromosome 3p

Answer

Chromosome 9q

Answer

Chromosome 13q

Question 7

A 50-year-old woman presents with a 5-year history of headaches, generalized tonic-clonic seizures, and bilateral leg weakness. Skull films reveal hyperostosis of the calvarium. Biopsy of the responsible lesion shows a whorling pattern of the cells. Which of the following is the most likely diagnosis?

Accepted Answer

Meningioma

Answer

Arachnoid cyst

Answer

Glioblastoma multiforme

Answer

Metastatic breast cancer

Question 8

Identify the rosette and its corresponding diagnosis.

Accepted Answer

Perivascular pseudorosette

Answer

Homer Wright rosette

Answer

True rosette

Answer

Flexner Wintersteiner rosette

Question 9

All of the following are neuronal tumors, EXCEPT:

Accepted Answer

Ependymoma

Answer

Gangliocytoma

Answer

Ganglioglioma

Answer

Neurocytoma

Question 10

Which chromosome mutation is associated with medulloblastoma?

Accepted Answer

Chromosome 17

Answer

Chromosome 16

Answer

Chromosome 18

Answer

Chromosome 19

Neuropathology — MCQs

Neuropathology — MCQs

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