General Pathology Practice Questions

Q: What is the most common odontogenic cyst?

Periapical cyst. **Explanation:** The **Periapical cyst** (also known as a Radicular cyst) is the most common odontogenic cyst, accounting for approximately 50–75% of all jaw cysts [1]. It is an **inflammatory cyst** that arises from the epithelial rests of Malassez in the periodontal ligament [1]. It typically develops at the apex of a non-vital tooth due to pulp necrosis caused by dental caries or trauma. **Analysis of Options:** * **A. Dentigerous cyst:** This is the most common **developmental** odontogenic cyst. It originates from the reduced enamel epithelium and surrounds the crown of an unerupted tooth (most commonly the mandibular third molar). * **C. Odontogenic Keratocyst (OKC):** Known for its aggressive behavior and high recurrence rate. It arises from the dental lamina and is histologically characterized by a parakeratinized stratified squamous epithelium. It is associated with **Gorlin-Goltz Syndrome**. * **D. Gorlin cyst:** Also known as Calcifying Odontogenic Cyst (COC). It is rare and characterized by the presence of "ghost cells" and focal calcifications. **High-Yield Clinical Pearls for NEET-PG:** * **Most common inflammatory cyst:** Periapical (Radicular) cyst [1]. * **Most common developmental cyst:** Dentigerous cyst. * **Radiological appearance:** Periapical cysts appear as well-defined unilocular radiolucencies at the root apex. * **Histology:** Look for **Rushton bodies** (eosinophilic, linear, or curved inclusions) in the epithelial lining of radicular cysts. * **Syndromic Association:** Multiple OKCs are a hallmark of **Nevoid Basal Cell Carcinoma Syndrome** (Gorlin-Goltz Syndrome). **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Head and Neck, pp. 741-742.

Q: Which of the following is true regarding Chediak-Higashi syndrome?

Defect in phagocytosis. **Explanation:** **Chediak-Higashi Syndrome (CHS)** is an autosomal recessive disorder caused by a mutation in the **LYST gene** (Lysosomal Trafficking Regulator). This mutation leads to defective vesicle fusion and intracellular trafficking [1]. **1. Why the correct answer is right:** The hallmark of CHS is the formation of **giant lysosomal granules** in white blood cells [1]. Because these granules cannot fuse properly with phagosomes, the process of **phagolysosome formation** is impaired. This results in a significant **defect in phagocytosis** (specifically the killing phase), leading to recurrent pyogenic infections [1]. **2. Why the incorrect options are wrong:** * **Neutropenia:** While mild neutropenia can occur in CHS due to ineffective granulopoiesis [1], the primary functional pathology defining the disease in the context of "defects of inflammation" is the phagocytic dysfunction. * **Agammaglobulinemia & IgA deficiency:** These are B-cell/humoral immunodeficiencies (e.g., Bruton’s or Selective IgA deficiency). CHS is a disorder of innate immunity (phagocyte function), not antibody production. **3. High-Yield Clinical Pearls for NEET-PG:** * **Microscopy:** Look for pathognomonic **giant azurophilic granules** in neutrophils on a peripheral smear [1]. * **Clinical Tetrad:** 1. **Partial Oculocutaneous Albinism** (due to giant melanosomes) [1]. 2. **Recurrent Pyogenic Infections** (Staph and Strep) [1]. 3. **Progressive Neuropathy** (nerve defects) [1]. 4. **Bleeding tendencies** (defective dense granules in platelets) [1]. * **Accelerated Phase:** Many patients develop a "hemophagocytic lymphohistiocytosis" (HLH)-like syndrome characterized by hepatosplenomegaly and pancytopenia. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of the Immune System, pp. 245-246.

Q: Which of the following conditions is characterized by a microdeletion?

DiGeorge syndrome. **Explanation:** **DiGeorge Syndrome (Correct Answer):** DiGeorge syndrome is a classic example of a **microdeletion syndrome**, specifically involving a submicroscopic deletion on the long arm of chromosome 22 (**22q11.2**) [1]. Because these deletions are too small to be detected by standard karyotyping, they require molecular techniques like **FISH** (Fluorescence In Situ Hybridization) or chromosomal microarray for diagnosis [1]. The deletion results in the maldevelopment of the **3rd and 4th pharyngeal pouches**, leading to the "CATCH-22" clinical constellation: **C**ardiac defects, **A**bnormal facies, **T**hymic hypoplasia (T-cell deficiency), **C**left palate, and **H**ypocalcemia (due to parathyroid aplasia). **Why other options are incorrect:** * **Beta Thalassemia:** This is primarily caused by **point mutations** (more common) or occasionally larger deletions in the $\beta$-globin gene on chromosome 11. It is classified as a single-gene (Mendelian) disorder, not a microdeletion syndrome. * **Marfan’s Syndrome:** This is an **Autosomal Dominant** disorder caused by a mutation in the **FBN1 gene** (encoding Fibrillin-1) on chromosome 15. It is a gene mutation, not a chromosomal microdeletion. **NEET-PG High-Yield Pearls:** * **Velocardiofacial Syndrome:** Also caused by the 22q11.2 deletion; it shares features with DiGeorge but emphasizes facial dysmorphism and palate anomalies [1]. * **Other Microdeletion Syndromes:** Prader-Willi and Angelman syndromes (15q11-q13 deletion) [2], Cri-du-chat (5p deletion), and Williams syndrome (7q11.23 deletion). * **Diagnostic Gold Standard:** FISH is the most frequently tested diagnostic modality for microdeletions in exams [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Genetic Disorders, pp. 172-173. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Genetic Disorders, pp. 181-183.

Question 1

What is the most common odontogenic cyst?

Accepted Answer

Periapical cyst

Answer

Dentigerous cyst

Answer

Odontogenic keratocyst

Answer

Gorlin cyst

Question 2

Multiple pulp stones are seen in which of the following conditions?

Accepted Answer

Ehlers-Danlos syndrome

Answer

Down syndrome

Answer

Marfan syndrome

Answer

Apert syndrome

Question 3

Which toll-like receptors are involved in the action of bacterial endotoxins?

Accepted Answer

TLR IV

Answer

TLR I

Answer

TLR II

Answer

TLR III

Question 4

Aneuploidy is due to:

Accepted Answer

Non-disjunction at meiosis

Answer

Mosaicism

Answer

Deletion

Answer

Translocation

Question 5

Shock is a circulatory disturbance characterized by

Accepted Answer

Decreased volume of circulating blood

Answer

Increased blood pressure

Answer

Elevated body temperature

Answer

Decreased volume of interstitial fluid

Question 6

Which of the following is true regarding Chediak-Higashi syndrome?

Accepted Answer

Defect in phagocytosis

Answer

Neutropenia

Answer

Agammaglobulinemia

Answer

IgA deficiency

Question 7

Which of the following conditions is characterized by a microdeletion?

Accepted Answer

DiGeorge syndrome

Answer

Beta thalassemia

Answer

Marfan's syndrome

Answer

All of the above

Question 8

Which stain is used for the identification of fat?

Accepted Answer

Congo red

Answer

Oil red O

Answer

Sudan black

Answer

Sudan III

Question 9

Metaplasia occurs in all of the following except:

Accepted Answer

Stem cells

Answer

Squamous cells

Answer

Columnar cells

Answer

Transitional cells

Question 10

Necrotizing lymphadenitis is seen in which of the following conditions?

Accepted Answer

Kikuchi disease

Answer

Hodgkin's disease

Answer

Kimura disease

Answer

Sarcoidosis

General Pathology — MCQs

General Pathology — MCQs

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