INI-CET 2024 - Pathology PYQs Practice Questions

Q: HBsAg is based on which principle

ELISA. ***ELISA*** - **Enzyme-linked immunosorbent assay (ELISA)** is a widely used laboratory test to detect and quantify antigens (like HBsAg) or antibodies in a sample. - It involves an enzyme-linked antibody that reacts with a substrate to produce a detectable signal, making it highly sensitive and specific for **HBsAg detection**. *Immunochromatography assays* - These are typically **rapid diagnostic tests (RDTs)** that provide quick qualitative results, often used for point-of-care testing. - While they can detect HBsAg, they generally have lower sensitivity and specificity compared to ELISA. *Chemiluminescence* - This is a detection method used in some immunoassays where a chemical reaction emits light, often providing higher sensitivity than colorimetric detection. - While it can be incorporated into HBsAg testing platforms, it is a *detection principle* rather than the primary assay principle like ELISA itself. *Immunofluorescence* - This technique uses **fluorescently labeled antibodies** to visualize antigens in cells or tissues under a fluorescence microscope [1]. - It is used for localization and identification of antigens, but not typically the primary method for routine quantitative HBsAg serology [1]. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. (Basic Pathology) introduces the student to key general principles of pathology, both as a medical science and as a clinical activity with a vital role in patient care. Part 2 (Disease Mechanisms) provides fundamental knowledge about the cellular and molecular processes involved in diseases, providing the rationale for their treatment. Part 3 (Systematic Pathology) deals in detail with specific diseases, with emphasis on the clinically important aspects., pp. 259-260. [Practice more Pathology PYQs on OnCourse]

Q: In which type of lung carcinoma is the p53 mutation most commonly observed?

Squamous cell carcinoma (SCC). ***Small cell carcinoma*** - **Small cell lung carcinoma (SCLC)** has the highest frequency of **p53 mutations**, occurring in approximately **90-95%** of cases. - These mutations are associated with the **aggressive nature** and **poor prognosis** of SCLC, contributing to its rapid growth and early metastasis. *Adenocarcinoma* - **Adenocarcinoma** has p53 mutations in approximately **50-60%** of cases, which is less frequent than SCLC. - This subtype is more commonly associated with **EGFR mutations** and **ALK rearrangements**, particularly in non-smokers. *Squamous cell carcinoma (SCC)* - **Squamous cell carcinoma** shows p53 mutations in about **70-80%** of cases, but still lower than SCLC. - It is more strongly associated with **smoking** and often displays mutations in **CDKN2A** and **PIK3CA** pathways. *Large cell carcinoma* - **Large cell carcinoma** has variable p53 mutation rates, typically **40-60%** of cases. - This subtype is less well-characterized molecularly and represents a **diagnosis of exclusion** among lung cancers. [Practice more Pathology PYQs on OnCourse]

Q: ER positivity is used as which of the following in the context of breast carcinoma?

Prognostic marker. ***Prognostic marker*** - **ER positivity** in **breast carcinoma** is primarily used as a **prognostic marker** indicating more favorable disease outcome [1]. - ER-positive tumors generally **grow more slowly**, are **less aggressive**, and have **better overall survival** compared to ER-negative tumors [2]. - While ER status also has **predictive value** for endocrine therapy response, its classification as a prognostic indicator reflects its association with inherently better tumor biology and patient outcomes [1]. - ER positivity correlates with **well-differentiated tumors** and **lower grade** malignancies. *Treatment option* - ER positivity is not a treatment itself, but rather a **biomarker** that guides treatment selection. - It identifies patients who may benefit from **endocrine therapy** (tamoxifen, aromatase inhibitors) [1]. *Molecular marker* - While ER is indeed a molecular marker (receptor protein detected by immunohistochemistry), this term is too **broad and non-specific**. - The question asks for the **specific clinical utility** of ER positivity, not its general classification. *Diagnostic marker* - ER status is **not used for initial diagnosis** of breast carcinoma. - Diagnosis requires **histopathological examination** of tissue biopsy. - ER testing is performed **after diagnosis** to characterize the tumor and guide management. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Breast, pp. 1059-1060. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Breast, pp. 1064-1066. [Practice more Pathology PYQs on OnCourse]

Q: Which is an intranuclear immunohistochemistry marker for neuroendocrine tumors?

INSM. ***INSM*** - **INSM1 (Insulinoma-associated protein 1)** is a highly sensitive and specific **transcription factor** expressed in neuroendocrine cells. - It exhibits **intranuclear staining** in immunohistochemistry, making it a reliable marker for neuroendocrine differentiation in tumors. *NCAM1/CD56* - **NCAM1/CD56** is a **cell surface adhesion molecule** - It shows **membranous or cytoplasmic staining** in immunohistochemistry, not intranuclear. *Chromogranin* - **Chromogranin A** is a **storage protein** found in dense core granules of neuroendocrine cells. [1] - It demonstrates **cytoplasmic staining** in immunohistochemistry and is a general neuroendocrine marker. [1] *Synaptophysin* - **Synaptophysin** is a **transmembrane glycoprotein** associated with synaptic vesicles. - It exhibits **cytoplasmic or membranous staining** in immunohistochemistry and is also a general neuroendocrine marker. [2] **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Liver And Biliary System Disease, pp. 419-420. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Gastrointestinal Tract, pp. 780-781. [Practice more Pathology PYQs on OnCourse]

Question 1

HBsAg is based on which principle

Accepted Answer

ELISA

Answer

Chemiluminescence

Answer

Immunofluorescence

Answer

Immunochromatography assays

Question 2

In which type of lung carcinoma is the p53 mutation most commonly observed?

Accepted Answer

Squamous cell carcinoma (SCC)

Answer

Adenocarcinoma

Answer

Large cell carcinoma

Answer

Small cell carcinoma

Question 3

ER positivity is used as which of the following in the context of breast carcinoma?

Accepted Answer

Prognostic marker

Answer

Treatment option

Answer

Molecular marker

Answer

Diagnostic marker

Question 4

Which is an intranuclear immunohistochemistry marker for neuroendocrine tumors?

Accepted Answer

INSM

Answer

NCAM1/CD56

Answer

Chromogranin

Answer

Synaptophysin

Question 5

A patient presents with neck swelling causing compression of the trachea and esophagus. Histopathological assessment reveals cell nests and pink extracellular amyloid stroma. What is the cell of origin of the tumor associated with these findings?

Accepted Answer

Parafollicular C cells

Answer

Hurthle cells

Answer

Follicular cells

Answer

Chief cells

Question 6

Molecular genetic testing is used to detect all of the following except?

Accepted Answer

Translocation

Answer

Deletion

Answer

Amplification

Answer

Point mutation

Question 7

To replenish the inventory, blood banks routinely issue blood packets which are close to the expiry date. Which of the following will be the closest to expiry date, according to the anticoagulant used and the method of storage of the packet:

Accepted Answer

SAGM, 25 days with irradiation

Answer

ACD, 14 days

Answer

CPDA, 27 days

Answer

SAGM, 35 days

Question 8

A 12-year-old Caucasian male presents with his mother to the pediatrician’s office complaining of right thigh pain. He reports that he has noticed slowly progressive pain and swelling over the distal aspect of his right thigh over the past two months. He denies any recent trauma to the area and his temperature is 100.9°F (38.3°C). On exam, there is swelling and tenderness overlying the distal right femoral diaphysis. Laboratory evaluation is notable for an elevated white blood cell (WBC) count and elevated erythrocyte sedimentation rate (ESR). A radiograph of the patient’s right leg is shown. Biopsy of the lesion demonstrates sheets of monotonous small round blue cells with minimal cytoplasm. Which of the following genetic mutations is most likely associated with this patient’s condition?

Accepted Answer

t(11;22)

Answer

RB1 inactivation

Answer

TP53 inactivation

Answer

t(8;14)

Answer

t(X;18)

INI-CET 2024 — Pathology