General Pathology Practice Questions

Q: Which of the following is NOT an inherited coagulation disorder?

Lupus anticoagulant. **Explanation:** The distinction between inherited and acquired thrombophilias is a high-yield topic in NEET-PG. **1. Why Lupus Anticoagulant is the correct answer:** **Lupus Anticoagulant (LA)** is an **acquired** autoimmune condition [1]. It is a type of antiphospholipid antibody (aPL) found in Antiphospholipid Antibody Syndrome (APS). Despite its name, it is a pro-thrombotic agent *in vivo*, leading to venous and arterial thrombosis, though it paradoxically prolongs the Activated Partial Thromboplastin Time (aPTT) *in vitro* [1]. **2. Why the other options are incorrect:** * **Factor V Leiden Mutation (Option C):** This is the **most common inherited cause** of hypercoagulability [1]. It involves a point mutation (G1691A) in the Factor V gene, making Factor V resistant to cleavage by activated Protein C (APC resistance) [1]. * **Protein C and S Deficiencies (Options A & B):** These are **autosomal dominant** inherited disorders. Protein C and S are natural anticoagulants (Vitamin K dependent) [2]. Their deficiency leads to an inability to inactivate Factors Va and VIIIa, resulting in a hypercoagulable state. **Clinical Pearls for NEET-PG:** * **Most common inherited thrombophilia:** Factor V Leiden [1]. * **Most common acquired thrombophilia:** Antiphospholipid Antibody Syndrome (APS) [1]. * **Warfarin-induced skin necrosis:** Classically seen in patients with **Protein C deficiency** when starting Warfarin without heparin bridging. * **Mixing Study:** Used to differentiate LA from factor deficiencies; LA will **not** correct upon mixing with normal plasma. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Hemodynamic Disorders, Thromboembolic Disease, and Shock, pp. 133-135. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 624-625.

Q: Which of the following is NOT a B cell marker?

CD-15. **Explanation:** The correct answer is **CD-15** because it is a marker for **Granulocytes** and **Reed-Sternberg (RS) cells** in Hodgkin Lymphoma, not B cells. **1. Why CD-15 is the correct answer:** CD-15 (also known as Lewis X) is a carbohydrate adhesion molecule. It is characteristically expressed on mature neutrophils, eosinophils, and monocytes. In clinical pathology, its most high-yield association is with **Classical Hodgkin Lymphoma**, where RS cells are typically **CD-15+ and CD-30+**. It is not expressed on normal or neoplastic B-lineage cells. **2. Analysis of B-cell markers (Incorrect Options):** * **CD-19:** This is the most specific and reliable pan-B cell marker [1]. It is expressed from the earliest stages of B-cell development (pro-B cell) until just before terminal differentiation into plasma cells [1]. * **CD-21:** Also known as **CR2 (Complement Receptor 2)**, it is the receptor for the C3d component of complement and the **Epstein-Barr Virus (EBV)** [1], [2]. It is found on mature B cells and follicular dendritic cells [1]. * **CD-23:** This is a low-affinity IgE receptor [1]. It is a key marker used to differentiate **CLL/SLL (CD-23 positive)** from Mantle Cell Lymphoma (CD-23 negative). **High-Yield Clinical Pearls for NEET-PG:** * **Pan-B cell markers:** CD-19, CD-20, CD-22, and PAX-5 (the most specific lineage marker). * **Plasma Cell markers:** CD-138 (Syndecan-1) and CD-38. * **CD-15 & CD-30:** Classic "diagnostic pair" for Reed-Sternberg cells in Hodgkin Lymphoma (except the Nodular Lymphocyte Predominant subtype, which is CD-20+). * **CD-21:** Remember it as the "entry portal" for EBV into B cells [2]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of White Blood Cells, Lymph Nodes, Spleen, and Thymus, p. 598. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of the Immune System, pp. 199-200.

Q: Two siblings have osteogenesis imperfecta, but their parents are normal. What is the mechanism of inheritance?

Germline mosaicism. **Explanation:** The correct answer is **Germline Mosaicism** (also known as Gonadal Mosaicism). **Why it is correct:** In this scenario, the parents are phenotypically normal (they do not carry the mutation in their somatic cells), yet they have **two** children with an autosomal dominant condition (Osteogenesis Imperfecta). If it were a simple "new mutation," it would be highly improbable for it to occur twice in the same family. Germline mosaicism occurs when a mutation happens post-zygotically during the parent's embryonic development, affecting only a subset of germ cells (sperm or eggs) but not the somatic cells [1]. Thus, the parent is healthy but can pass the mutation to multiple offspring. **Why other options are incorrect:** * **Anticipation:** Refers to the increasing severity or earlier onset of a disease in successive generations, typically seen in trinucleotide repeat disorders (e.g., Huntington’s, Fragile X). * **Genomic Imprinting:** Involves differential expression of a gene depending on whether it is inherited from the mother or father (e.g., Prader-Willi and Angelman syndromes). * **New Mutation (De novo):** While Osteogenesis Imperfecta often results from new mutations, a single new mutation cannot explain why **two** siblings are affected if the parents are normal. **NEET-PG High-Yield Pearls:** * **Classic Example:** Germline mosaicism is the most common explanation when healthy parents have multiple children with **Osteogenesis Imperfecta** or **Duchenne Muscular Dystrophy (DMD)**. * **Recurrence Risk:** In germline mosaicism, the recurrence risk for siblings is significantly higher than the general population risk, despite normal parental testing. * **Definition:** Presence of two or more genetically different cell lines in the gonads [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Genetic Disorders, pp. 170-171.

Question 1

Eosinophil production is increased by which of the following cytokines?

Accepted Answer

IL-5

Answer

IL-1

Answer

IL-6

Answer

TNF-A

Question 2

All of the following are true of red infarction, except?

Accepted Answer

Occurs in end arterial occlusion

Answer

Occurs with venous occlusion

Answer

Seen in loose tissues

Answer

Occurs in previously congested tissue

Question 3

What is the mode of genetic inheritance for hemophilia?

Accepted Answer

Sex-linked recessive

Answer

Sex-linked dominant

Answer

Autosomal dominant

Answer

Autosomal recessive

Question 4

Which of the following is NOT an inherited coagulation disorder?

Accepted Answer

Lupus anticoagulant

Answer

Protein C deficiency

Answer

Protein S deficiency

Answer

Factor V Leiden mutation

Question 5

Which of the following is NOT a B cell marker?

Accepted Answer

CD-15

Answer

CD-19

Answer

CD-21

Answer

CD-23

Question 6

All the following receptors play a role in phagocytosis EXCEPT-

Accepted Answer

G protein coupled receptor

Answer

Mannose receptors

Answer

Scavenger receptors

Answer

Receptors for opsonins

Question 7

Two siblings have osteogenesis imperfecta, but their parents are normal. What is the mechanism of inheritance?

Accepted Answer

Germline mosaicism

Answer

Anticipation

Answer

Genomic imprinting

Answer

New mutation

Question 8

Which of the following is used as a fungal stain in tissue biopsy sections?

Accepted Answer

PAS

Answer

Alizarin red

Answer

LPCB

Answer

Masson Trichrome

Question 9

Which of the following is NOT a tumor that typically undergoes spontaneous resolution?

Accepted Answer

Osteogenic sarcoma

Answer

Malignant melanoma

Answer

Cholangiocarcinoma

Answer

Retinoblastoma

Question 10

All endothelial cells produce thrombomodulin except those found in which of the following circulations?

Accepted Answer

Cerebral microcirculation

Answer

Hepatic circulation

Answer

Cutaneous circulation

Answer

Renal circulation

General Pathology — MCQs

General Pathology — MCQs

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