FMGE 2025 - Pathology PYQs Practice Questions

Q: A 9-month-old child was admitted to ICU with a history of recurrent sinusitis and otitis media by Staphylococcus aureus. Blood test shows decreased serum IgA, IgG, IgM, IgE, and plasma B cells. What is the diagnosis?

Bruton syndrome. ***Bruton syndrome***- This diagnosis (X-linked agammaglobulinemia or XLA) is defined by the failure of **B cell maturation** due to a mutation in the **BTK gene**, leading to near-total absence of mature B cells and plasma cells.- The clinical presentation is recurrent infections, often *S. aureus* and encapsulated bacteria, correlated with the drastic reduction of all serum **immunoglobulin levels** (IgA, IgG, IgM, IgE).*Ataxia telangiectasia*- This is an **autosomal recessive** T-cell/B-cell defect associated with defects in **DNA repair** (ATM gene), causing progressive cerebellar ataxia and oculocutaneous telangiectasias.- While associated with immunodeficiency, it typically presents with low **IgA** and **IgE**, not the complete absence of plasma B cells seen here.*Chronic granulomatous disease*- This is a phagocytic disorder due to a defect in the **NADPH oxidase** complex, preventing neutrophils from generating a respiratory burst necessary to kill catalase-positive organisms (like *S. aureus*).- Although the child has *S. aureus* infection, **serum Ig and B cell levels** remain normal, which contradicts the profound pan-hypogammaglobulinemia seen in this scenario.*DiGeorge syndrome*- Caused by defective development of the 3rd and 4th pharyngeal pouches, resulting in **T-cell deficiency** (thymic hypoplasia), **hypocalcemia**, and cardiac defects.- The primary immunodeficiency affects T cells, leading to susceptibility to **viral and fungal infections**; B cell numbers are usually normal, even though antibody production might be secondarily impaired. [Practice more Pathology PYQs on OnCourse]

Q: Edematous villi with chromosome XY were found. What will be the diagnosis?

Complete mole. ***Correct: Complete mole*** The finding of **edematous/hydropic villi** with a diploid karyotype (**46,XY**) is characteristic of a **Complete hydatidiform mole**. - A complete mole results from the fertilization of an 'empty' ovum by a single sperm (which duplicates, 46,XX) or two sperm (**46,XY**), leading to no fetal parts and diffuse **trophoblastic proliferation**. *Incorrect: Partial mole* A **Partial mole** is almost always triploid (e.g., **69,XXY** or 69,XXX), resulting from fertilization of a normal ovum by two sperm. - Histologically, it presents with a mixture of **normal and abnormal** (hydropic) villi, focal trophoblastic changes, and often identifiable **fetal parts**. *Incorrect: Cyst* This is a nonspecific term referring to a fluid-filled sac and does not account for the specific histological findings of abnormal **placental tissue** (edematous villi). - The presence of an abnormal **diploid karyotype (XY)** points towards a specific gestational trophoblastic disease rather than a generalized cystic structure. *Incorrect: Ectopic pregnancy* Ectopic pregnancy involves implantation outside the uterine cavity and, if villi are present, they are usually **normal chorionic villi** and not diffusely edematous. - The histological finding of **diffuse edematous villi** accompanied by the specific complete mole karyotype (**46,XY**) excludes a typical ectopic pregnancy. [Practice more Pathology PYQs on OnCourse]

Q: What is the earliest time after myocardial infarction when triphenyl tetrazolium chloride (TTC) staining can detect infarcted tissue?

3 hours. ***3 hours***- **TTC (Triphenyl Tetrazolium Chloride)** staining detects viable myocardium by reacting with **lactate dehydrogenase** (LDH) and other mitochondrial dehydrogenases, resulting in a **brick-red color** [1].- Necrotic myocardium loses these enzymes, preventing the color change and leaving the infarcted tissue **pale yellow**; this process usually takes at least **3 hours** post-occlusion to be grossly detectable [1].*1 hour*- The time interval is too short for the complete depletion of **dehydrogenases** from the infarcted cells necessary to prevent the TTC reaction and produce a visually distinct **pale area**.- Reliable gross detection by TTC requires cellular necrosis advanced enough to cause enzyme leakage, which typically requires more time than 1 hour [1].*30 minutes*- At 30 minutes post-MI, myocardial damage is often still in the stage of **reversible injury**, and the cell membranes and internal enzyme systems are still largely intact [2].- This limited timeframe does not allow for sufficient enzyme leakage or inactivation required to produce a clear negative (unstained) reaction with the **tetrazolium salt** [1].*Immediately*- Immediate staining will show uniformly red tissue because sufficient time has not passed for the irreversible cell injury (**necrosis**) and subsequent loss of intrinsic **enzymatic activity**.- Myocardium must undergo several hours of severe ischemia and necrosis before the gross chemical findings detected by **TTC** become apparent [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Heart, pp. 552-554. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Heart, p. 552. [Practice more Pathology PYQs on OnCourse]

Question 1

A 9-month-old child was admitted to ICU with a history of recurrent sinusitis and otitis media by Staphylococcus aureus. Blood test shows decreased serum IgA, IgG, IgM, IgE, and plasma B cells. What is the diagnosis?

Accepted Answer

Bruton syndrome

Answer

Chronic granulomatous disease

Answer

DiGeorge syndrome

Answer

Ataxia telangiectasia

Question 2

Edematous villi with chromosome XY were found. What will be the diagnosis?

Accepted Answer

Complete mole

Answer

Ectopic pregnancy

Answer

Partial mole

Answer

Cyst

Question 3

A child diagnosed with von Willebrand disease requires an understanding of the role of von Willebrand factor (vWF). What does von Willebrand factor primarily combine with?

Accepted Answer

Glycoprotein Ib

Answer

Prothrombin

Answer

ADP

Answer

Platelet factor 3

Question 4

A male presents with a history of vestibular schwannoma and psammoma bodies in the brain. Which of the following is the most likely diagnosis?

Accepted Answer

Meningioma

Answer

Oligodendroglioma

Answer

Pilocytic astrocytoma

Answer

GBM (Glioblastoma Multiforme)

Question 5

What is the earliest time after myocardial infarction when triphenyl tetrazolium chloride (TTC) staining can detect infarcted tissue?

Accepted Answer

3 hours

Answer

1 hour

Answer

30 minutes

Answer

Immediately

Question 6

Which of the following is a change seen in irreversible cell injury?

Accepted Answer

Amorphous density of mitochondria

Answer

Cellular Swelling

Answer

Bleb formation

Answer

Clumping of chromatin

Question 7

Histopathological examination showed follicular cells with abundant pink eosinophilic cytoplasm WITHOUT nuclear grooves or ground-glass nuclei. This is most characteristic of?

Accepted Answer

Follicular CA

Answer

Papillary CA

Answer

Medullary CA

Answer

Anaplastic CA

Question 8

Which of the following is not related to disease progression?

Accepted Answer

Duration

Answer

Depth

Answer

Stage of Cancer

Answer

Site

Question 9

What is the primary mechanism behind tissue damage in long-standing diabetes?

Accepted Answer

Hyperglycemia

Answer

Insulin resistance

Answer

Sorbitol accumulation

Answer

Decreased insulin secretion

Question 10

A child presents with micrognathia and low-set ears. These clinical features are commonly associated with which type of genetic abnormality?

Accepted Answer

Deletion

Answer

Amplification

Answer

Inversion

Answer

Translocation

FMGE 2025 — Pathology