NEET-PG 2025 - Pathology Practice Questions

Q: The pedigree chart shown in the image demonstrates a specific pattern of inheritance. Which of the following conditions is most likely to follow this pattern of inheritance?

Kearns-Sayre syndrome. ***Kearns-Sayre syndrome*** - This condition is caused by large-scale deletions in **mitochondrial DNA (mtDNA)**, leading to a pattern of **maternal inheritance** (non-Mendelian) [1]. - Mitochondrial disorders are passed exclusively from the mother, affecting all offspring, which defines this specific inheritance pattern [1]. *Duchenne muscular dystrophy* - This follows an **X-linked recessive** pattern of inheritance, where the defective gene is located on the X chromosome [2]. - It primarily affects males, with mothers typically being asymptomatic carriers, clearly distinguishing it from mitochondrial inheritance [2]. *Huntington's disease* - This is an **autosomal dominant** disorder, meaning it is caused by a mutation on a non-sex chromosome and can be passed from either parent [3]. - It affects both males and females equally, with a 50% chance of transmission regardless of the child's sex [3]. *Marfan syndrome* - This is an **autosomal dominant** condition resulting from a mutation in the **FBN1 gene** (nuclear DNA) [3]. - The inheritance does not rely exclusively on the maternal line, as expected in an autosomal dominant Mendelian disorder [3]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Genetic Disorders, p. 181. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Genetic Disorders, p. 151. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Genetic Disorders, pp. 149-150.

Q: A middle-aged man from an endemic region presents with progressive swelling of the lower limb. A peripheral blood smear shows the following structure. What is the most likely cause of his limb swelling?

Lymphatic obstruction. ***Lymphatic obstruction*** - The image displays **microfilariae** (suggesting **Lymphatic Filariasis**), where the adult worms settle in the lymphatics, physically blocking flow. - This obstruction results in chronic, progressive edema (known as **lymphedema** or **elephantiasis**) due to the failure of lymphatic drainage in the affected limb. *Hypoalbuminemia* - Edema from **hypoalbuminemia** is due to low plasma oncotic pressure and typically results in generalized, pitting edema, which is not characteristic of chronic, localized filarial swelling. - While malnutrition might co-exist, the core pathology shown by the presence of **microfilariae** points specifically to mechanical lymphatic blockage. *Hypoproteinemia* - **Hypoproteinemia** is a general cause of edema via reduced **oncotic pressure**, leading to fluid shift into the interstitial spaces, usually causing generalized rather than localized swelling. - This systemic cause does not account for the specific parasitic damage to the lymphatics demonstrated by the presence of the **filarial worms**. *increased hydrostatic pressure* - Increased hydrostatic pressure (e.g., in conditions like DVT or CHF) leads to fluid leakage from capillaries, causing pitting edema. - The root cause here is the parasitic **destruction and obstruction of lymph nodes and channels**, which specifically impairs lymph return, not capillary hydrostatic pressure regulation.

Q: A 15-year-old tall boy with long limbs presents to the OPD. On ocular examination, bilateral ectopia lentis is noted. Which gene is most likely affected in this inherited disorder?

FBN1 (Fibrillin-1). ***FBN1 (Fibrillin-1)*** - The clinical triad of tall stature/long limbs (**Marfanoid habitus**) and **ectopia lentis** (lens dislocation) is characteristic of **Marfan syndrome** [1]. - Marfan syndrome is caused by an autosomal dominant mutation in the **FBN1 gene** on chromosome 15, which codes for the connective tissue protein **Fibrillin-1** [1]. *COL5A* - Mutations in **COL5A** (Type V collagen) are typically associated with the Classical type of **Ehlers-Danlos syndrome (EDS)**. - Clinical features of EDS primarily include **skin hyperextensibility** and **joint hypermobility**, which are not the most prominent features in this presentation. *PAX6* - The **PAX6 gene** is a master gene for eye development, and its mutation primarily causes **Aniridia** (absence of the iris) or other widespread ocular developmental defects. - Although ophthalmological findings are present, aniridia is not the key ocular finding, making PAX6 mutation an incorrect association. *TGF-β R2* - Mutations in **TGF-β R2** are linked to **Loeys-Dietz syndrome**, which involves severe **aortic root dilation** and craniocervical instability [1]. - While Loeys-Dietz syndrome presents with Marfanoid skeletal features, **ectopia lentis** is rare or absent, differentiating it from Marfan syndrome (FBN1) [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Genetic Disorders, pp. 153-154.

Q: A 25-year old patient who had a Road traffic accident was initially conscious but later became unconscious and subsequently died. On postmortem examination, multiple petechial hemorrhages are seen in the corpus callosum, what is the probable diagnosis?

Diffuse axonal injury. ***Diffuse axonal injury*** - The characteristic finding of **multiple petechial hemorrhages** (microhemorrhages) specifically in deep structures like the **corpus callosum** and brainstem is the pathological hallmark of **Diffuse Axonal Injury** (DAI) [1]. - DAI results from severe acceleration/deceleration (shearing) forces during trauma, leading to widespread axonal disruption, which explains the progression from initial consciousness to coma [1]. *EDH* - Epidural Hematoma (EDH) involves an arterial bleed, typically from the **middle meningeal artery**, causing a hematoma external to the dura mater [1]. - Although EDH often presents with a clinical **lucid interval**, the post-mortem findings are limited to the hematoma collection external to the brain substance, not deep parenchymal petechiae [1]. *SDH* - Subdural hematoma (SDH) is caused by the tearing of **bridging veins** and collects between the dura and arachnoid mater. - While SDH can cause delayed deterioration due to haematoma expansion, the specific microscopic deep white matter hemorrhages described are the defining feature of **DAI**, not SDH. *Contusion* - Cerebral contusions present as focal areas of hemorrhagic necrosis, typically at the site of impact (coup) or opposite side (contrecoup), commonly affecting the frontal and temporal poles [1]. - Unlike DAI, contusions are macroscopic hemorrhagic lesions visible on gross examination, not the characteristic microscopic petechial hemorrhages in deep white matter structures like the corpus callosum [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Central Nervous System, pp. 1262-1264.

Q: A patient presents with morning stiffness and tests positive for anti-CCP antibodies. Which of the following histological features is most characteristic of the underlying disease?

Pannus formation and erosive joint damage. ***Pannus formation and erosive joint damage*** - **Anti-CCP antibodies** along with morning stiffness heavily suggest **Rheumatoid Arthritis (RA)**, whose defining feature is the proliferation of hyperplastic synovial tissue known as the **pannus** [1]. - The **pannus** invades and destroys the adjacent articular cartilage and subchondral bone, leading to characteristic joint **erosions** [1] and deformities [3]. *Non-caseating granulomas* - These histological findings are characteristic of systemic inflammatory conditions such as **Sarcoidosis** or certain types of inflammatory bowel disease like **Crohn's disease**. - Granulomas are distinct structures involving epithelioid macrophages and do not represent the primary destructive pathology in RA [1]. *Subepidermal blister with IgA deposits* - This pathology is specific to the skin disease **Dermatitis Herpetiformis**, often associated with Celiac disease. - It involves IgA deposition in the dermal papillae, which is completely irrelevant to the underlying joint pathology of RA. *Tophi with monosodium urate crystals* - These structures are the histological hallmarks of chronic **Gout**, resulting from the deposition of precipitated **monosodium urate** crystals usually surrounded by foreign-body giant cells [2]. - Gouty arthritis is clinically and immunologically distinct from RA, lacking anti-CCP antibody positivity. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Osteoarticular And Connective Tissue Disease, pp. 677-678. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, pp. 1218-1220. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, p. 1214.

Q: Patient presents with dry cough, dyspnea and stridor. HPE of hilar LN shows stellate granulomas with giant cells and circular lamellated concretions on histopathology. Which of the following is the most likely diagnosis?

Sarcoidosis. ***Sarcoidosis*** - The histopathological finding of **stellate granulomas** (non-caseating) in the lymph node, combined with **circular lamellated concretions** (**Schaumann bodies**), is highly characteristic, if not pathognomonic, of **Sarcoidosis**. - The presentation of hilar lymphadenopathy (inferred from HPE of hilar LN) with dry cough and dyspnea is the most common manifestation of pulmonary sarcoidosis [1]. *Tuberculosis* - **Tuberculosis** typically results in granulomas that display **caseating necrosis** (cheese-like), a feature absent from the description of stellate granulomas. - Although TB causes hilar lymphadenopathy, it does not typically produce **Schaumann bodies** or exhibit the distinct, non-necrotizing stellate granuloma morphology. *GPA* - **Granulomatosis with Polyangiitis (GPA)** is characterized by **necrotizing vasculitis** and widespread **necrotizing granulomatous inflammation** involving the upper and lower respiratory tracts. - GPA granulomas are generally large and necrotizing, and they do not contain the specific organization or inclusion bodies like **Schaumann bodies** seen in sarcoidosis. *Hypersensitivity pneumonitis* - This condition involves scattered, often poorly formed, **non-necrotizing granulomas** typically located in the lung interstitium (centrilobular distribution). - Unlike sarcoidosis, generalized hilar lymph node involvement and the presence of classical **Schaumann bodies** or well-defined stellate granulomas are rare in Hypersensitivity Pneumonitis. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Lung, pp. 700-701.

Question 1

The pedigree chart shown in the image demonstrates a specific pattern of inheritance. Which of the following conditions is most likely to follow this pattern of inheritance?

Accepted Answer

Kearns-Sayre syndrome

Answer

Marfan syndrome

Answer

Duchenne muscular dystrophy

Answer

Huntington's disease

Question 2

A middle-aged man from an endemic region presents with progressive swelling of the lower limb. A peripheral blood smear shows the following structure. What is the most likely cause of his limb swelling?

Accepted Answer

Lymphatic obstruction

Answer

Hypoalbuminemia

Answer

Hypoproteinemia

Answer

Increased hydrostatic pressure

Question 3

A 45-year-old female presents with a 2-year history of progressive unilateral hearing loss, tinnitus, and unsteadiness. An MRI scan reveals a well-defined tumor located in the cerebellopontine angle (CPA). A surgical resection is performed, and subsequent histopathological examination of the tumor tissue is given below. Based on these histopathological findings, what is the most likely diagnosis?

Accepted Answer

Schwannoma

Answer

Meningioma

Answer

Neurofibroma

Answer

Ependymoma

Question 4

A 15-year-old tall boy with long limbs presents to the OPD. On ocular examination, bilateral ectopia lentis is noted. Which gene is most likely affected in this inherited disorder?

Accepted Answer

FBN1 (Fibrillin-1)

Answer

COL5A

Answer

PAX6

Answer

TGF-β R2

Question 5

A 25-year old patient who had a Road traffic accident was initially conscious but later became unconscious and subsequently died. On postmortem examination, multiple petechial hemorrhages are seen in the corpus callosum, what is the probable diagnosis?

Accepted Answer

Diffuse axonal injury

Answer

Epidural hematoma

Answer

Subdural hematoma

Answer

Contusion

Question 6

A patient presents with morning stiffness and tests positive for anti-CCP antibodies. Which of the following histological features is most characteristic of the underlying disease?

Accepted Answer

Pannus formation and erosive joint damage

Answer

Subepidermal blister with IgA deposits

Answer

Tophi with monosodium urate crystals

Answer

Non-caseating granulomas

Question 7

Patient presents with dry cough, dyspnea and stridor. HPE of hilar LN shows stellate granulomas with giant cells and circular lamellated concretions on histopathology. Which of the following is the most likely diagnosis?

Accepted Answer

Sarcoidosis

Answer

GPA

Answer

Hypersensitivity pneumonitis

Answer

Tuberculosis

NEET-PG 2025 — Pathology