NEET-PG 2015 - Pathology Practice Questions

Q: Medulloblastoma arises exclusively from the cells of

Immature embryonal cells. ***Immature embryonal cells*** - **Medulloblastoma** is a malignant **embryonal tumor** of the cerebellum, exclusively arising from primitive neuroectodermal cells. - These tumors are thought to originate from remnants of the **external granular layer** of the cerebellum or other primitive neuroectodermal cells. *Ependymal cells* - Tumors arising from **ependymal cells** are called **ependymomas**, which typically occur within the ventricles of the brain or spinal cord. - Ependymomas have distinct histological features and clinical behavior compared to medulloblastomas. *Neurons* - Tumors primarily composed of neurons or with significant neuronal differentiation include **gangliogliomas** and **central neurocytomas**. - **Medulloblastomas** largely consist of undifferentiated, small round cells with minimal evidence of neuronal maturation. *Spindle-shaped cells* - **Spindle-shaped cells** are characteristic of various tumor types, including some **gliomas** (e.g., pilocytic astrocytoma) or mesenchymal tumors. - While some medulloblastoma variants can show desmoplastic features, the hallmark cell type is a small, round, blue embryonal cell.

Q: Blebs are associated with which type of cell injury?

Both. ***Correct: Both*** - Blebs (surface membrane protrusions) are associated with **both reversible and irreversible cell injury** - In **reversible injury**: cellular swelling causes cytoskeletal disruption leading to bleb formation; these blebs can resolve if the injurious stimulus is removed - In **irreversible injury**: more extensive and widespread blebbing occurs during apoptosis and necrosis, associated with cell death pathways - The key difference is in the **extent and reversibility**, not the presence or absence of blebs *Incorrect: Reversible* - While blebs do occur in reversible injury, this option is incomplete as it excludes their occurrence in irreversible injury - Blebs are seen in both types of cellular injury, making "reversible" alone an inadequate answer *Incorrect: Irreversible* - While blebs are prominent in irreversible injury (apoptosis and necrosis), they also occur in reversible injury - Standard pathology texts (Robbins) describe bleb formation as a feature of cellular swelling in reversible injury - This option is incomplete as it excludes reversible injury *Incorrect: None of the options* - This is incorrect because blebs are definitively associated with cell injury (both reversible and irreversible types) - Bleb formation is a well-recognized morphological change in cellular pathology

Q: Investigation of choice for confirming Henoch Schönlein Purpura is

Renal Biopsy. ***Renal Biopsy*** - **Biopsy (renal or skin)** showing **IgA deposition** is the **confirmatory investigation** for Henoch-Schönlein Purpura (HSP) when histological confirmation is needed [1]. - **Renal biopsy** demonstrates characteristic **IgA-dominant immune deposits** in the mesangium and glomerular capillaries, along with **mesangial proliferation** [1]. - While HSP is primarily a **clinical diagnosis** based on palpable purpura, age < 20 years, abdominal pain, and renal involvement, biopsy provides **definitive confirmation** in atypical presentations or when diagnosis is uncertain. - Immunofluorescence showing **IgA deposition** is the pathognomonic finding [1]. *Serum IgA levels* - Serum IgA levels may be elevated in approximately **50% of HSP cases**, but this is **neither sensitive nor specific**. - **Normal serum IgA does NOT exclude HSP**, making it unreliable as a confirmatory test. - Elevated IgA can occur in many other conditions (IgA nephropathy without vasculitis, liver disease, infections). - Provides only supportive evidence, not confirmation. *CRP levels* - **C-reactive protein (CRP)** is a **non-specific inflammatory marker** that may be elevated in HSP. - Cannot distinguish HSP from other inflammatory or infectious conditions. - Has no role in confirming the diagnosis. *DTPA* - **DTPA scan** assesses **renal perfusion and function** but does not provide diagnostic information about the underlying pathology. - Cannot detect the characteristic **IgA-mediated vasculitis** of HSP. - Not useful for confirming the diagnosis. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Diseases Of The Urinary And Male Genital Tracts, pp. 526-527.

Q: Fat necrosis is common in:

Breast. ***Breast*** - **Fat necrosis** in the breast is a relatively common benign condition, often resulting from trauma, surgery, or radiation. - It presents as a palpable lump that can mimic malignancy, making its differentiation crucial. *Retroperitoneal fat* - While fat necrosis can occur in the retroperitoneum, particularly in cases of **acute pancreatitis**, it is not considered "common" in this location independently [1]. - The primary tissue affected in pancreatitis is the pancreas itself, with necrosis extending to surrounding fat [1]. *Omentum* - **Omental fat necrosis** can occur but is rare and usually associated with torsion of the omentum or, less commonly, blunt abdominal trauma. - It is not a common site for isolated fat necrosis compared to the breast. *All of the options* - Although fat necrosis can occur in all these locations under specific circumstances, it is not "common" in all of them when considering the typical incidence of the condition. - **Breast fat necrosis** is more frequently encountered in clinical practice than in the omentum or retroperitoneal region. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Pancreas, p. 895.

Q: Which of the following is the most frequent primary malignant tumor of the CNS?

Glioblastoma multiforme. ***Glioblastoma multiforme*** - **Glioblastoma multiforme (GBM)** is the most common and aggressive primary malignant brain tumor in adults [1]. - It is a **grade IV astrocytoma**, characterized by rapid growth, necrosis, and microvascular proliferation [1]. *Oligodendroglioma* - **Oligodendrogliomas** are primary glial tumors but are less common than GBM. - They typically have a more indolent course than GBM and are often characterized by **IDH mutations** and **1p/19q co-deletion**. *Medulloblastoma* - **Medulloblastoma** is the most common malignant brain tumor in children, but it is rare in adults [2]. - It arises in the **cerebellum** and is a type of embryonal tumor [2]. *Meningioma* - **Meningiomas** are the most common primary brain tumors overall, but they are typically **benign** and originate from the meninges. - While they can be symptomatic due to compression, they are not primarily malignant in the way GBM is. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Central Nervous System, pp. 1308-1310. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Manifestations Of Central And Peripheral Nervous System Disease, pp. 725-726.

Q: Autosomal recessive Polycystic kidneys - all are true except -

USG shows salt and pepper appearance. ***USG shows salt and pepper appearance*** - The **"salt and pepper" appearance** on imaging is characteristic of **autosomal dominant polycystic kidney disease (ADPKD)** due to multiple renal cysts of varying sizes and associated vascular calcifications, not autosomal recessive polycystic kidney disease (ARPKD). - ARPKD typically presents with **enlarged, hyperechoic kidneys** with loss of corticomedullary differentiation on ultrasound due to numerous small cysts. *Defective gene is PKHD1* - The dysfunctional gene in **autosomal recessive polycystic kidney disease (ARPKD)** is indeed **PKHD1**, located on chromosome 6. - This gene encodes for **fibrocystin/polyductin**, a protein primarily found in renal and biliary epithelial cells, whose mutation leads to cyst formation. *Both kidneys show innumerable cysts* - ARPKD is characterized by **bilateral involvement** with diffuse dilation of the collecting ducts, leading to innumerable small cysts in both kidneys. - These cysts cause significant **renal enlargement** and can lead to severe renal dysfunction. *Seen in adults* - **Autosomal recessive polycystic kidney disease (ARPKD)** typically manifests in **infancy or childhood**, often prenatally or neonatally. - While some milder forms may present later in childhood, it is **not generally seen in adults**; adult-onset polycystic kidney disease is usually autosomal dominant (ADPKD) [1].

Q: Effect of hypoparathyroidism on bones include -

None of the Above. ***None of the Above*** - **Hypoparathyroidism** leads to **decreased parathyroid hormone (PTH)** levels, resulting in **hypocalcemia** and **hyperphosphatemia**. [3] - Unlike hyperparathyroidism, which causes bone resorption, hypoparathyroidism is generally associated with **increased bone density** due to reduced osteoclastic activity. *Brown tumours* - **Brown tumors** are focal lesions caused by **osteoclastic activity** and fibrous tissue replacement in severe **hyperparathyroidism**, which is the opposite of the condition described. [1], [2] - They are a manifestation of **osteitis fibrosa cystica**, a skeletal complication of prolonged excess PTH. [2] *Subperiosteal Resorption of Bone* - **Subperiosteal bone resorption** is a classic radiographic sign of **hyperparathyroidism**, where excessive PTH causes osteoclasts to erode bone, particularly in the phalanges. [1] - This process is driven by **elevated PTH**, which is absent in hypoparathyroidism. *Multiple Cysts in Bone* - **Multiple cysts in bone** (also known as osteitis fibrosa cystica) are characteristic of **severe hyperparathyroidism**, resulting from excessive bone remodeling and fibrous tissue proliferation. [2] - Hypoparathyroidism does not cause bone cysts; instead, it tends to lead to **increased bone mineral density**. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, pp. 1194-1195. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Endocrine System, pp. 1105-1106. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Endocrine System, pp. 1106-1107.

Question 1

Medulloblastoma arises exclusively from the cells of

Accepted Answer

Immature embryonal cells

Answer

Ependymal cells

Answer

Neurons

Answer

Spindle-shaped cells

Question 2

Blebs are associated with which type of cell injury?

Accepted Answer

Both

Answer

Reversible

Answer

Irreversible

Answer

None of the options

Question 3

Investigation of choice for confirming Henoch Schönlein Purpura is

Accepted Answer

Renal Biopsy

Answer

Serum IgA levels

Answer

CRP levels

Answer

DTPA

Question 4

Fat necrosis is common in:

Accepted Answer

Breast

Answer

Retroperitoneal fat

Answer

Omentum

Answer

All of the options

Question 5

Which of the following is the most frequent primary malignant tumor of the CNS?

Accepted Answer

Glioblastoma multiforme

Answer

Oligodendroglioma

Answer

Medulloblastoma

Answer

Meningioma

Question 6

Autosomal recessive Polycystic kidneys - all are true except -

Accepted Answer

USG shows salt and pepper appearance

Answer

Defective gene is PKHD1

Answer

Both kidneys show innumerable cysts

Answer

Seen in adults

Question 7

Effect of hypoparathyroidism on bones include -

Accepted Answer

None of the Above

Answer

Brown tumours

Answer

Subperiosteal Resorption of Bone

Answer

Multiple Cysts in Bone

NEET-PG 2015 — Pathology