Neoplasia — MCQs

Neoplasia Indian Medical PG Practice Questions and MCQs

Question 811: Which of the following is a marker of GIST?

A. PDGFRA
B. C-kit (Correct Answer)
C. NRG1
D. Nestin

Explanation: ***C-kit*** - **C-kit (CD117)** is a proto-oncogene that encodes a **tyrosine kinase receptor**, and its expression is a defining characteristic of **gastrointestinal stromal tumors (GISTs)**. - Approximately 95% of GISTs express C-kit, making it an essential **diagnostic marker** and a target for therapy (e.g., **imatinib**). *PDGFRA* - **PDGFRA (Platelet-Derived Growth Factor Receptor Alpha)** mutations occur in approximately 5-10% of GISTs, typically in those that are **C-kit negative** [1]. - While PDGFRA mutations are clinically relevant and can be targeted by imatinib, **C-kit/CD117 remains the primary immunohistochemical marker** used for GIST diagnosis [1]. *NRG1* - **NRG1 (Neuregulin 1)** is a protein from the NRG family that plays a role in cell signaling and development, particularly in the nervous system and heart. - It is not associated with the diagnosis or pathophysiology of GISTs. *Nestin* - **Nestin** is an intermediate filament protein primarily expressed in **neural stem cells** and is a marker of neural progenitor cells and some highly proliferative tumor cells. - It does not serve as a diagnostic marker for GISTs. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Gastrointestinal Tract, pp. 782-783.

Question 812: Which is an intranuclear immunohistochemistry marker for neuroendocrine tumors?

A. NCAM1/CD56
B. Chromogranin
C. Synaptophysin
D. INSM (Correct Answer)

Explanation: ***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.

Question 813: ER positivity is used as which of the following in the context of breast carcinoma?

A. Treatment option
B. Prognostic marker (Correct Answer)
C. Molecular marker
D. Diagnostic marker

Explanation: ***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.

Question 814: A 52-year-old male with a history of smoking presents with a persistent cough and hemoptysis. A CT scan reveals a central lung mass, and a biopsy shows small, round, blue cells with neuroendocrine differentiation. What is the most likely diagnosis?

A. Adenocarcinoma
B. Squamous cell carcinoma
C. Small cell carcinoma (Correct Answer)
D. Large cell carcinoma

Explanation: ***Small cell carcinoma*** - The presence of **small, round, blue cells** with **neuroendocrine differentiation** in the biopsy is characteristic of small cell lung carcinoma [1]. - It is strongly associated with **smoking** and typically presents as a **central lung mass** with symptoms like **persistent cough** and **hemoptysis** [1]. *Squamous cell carcinoma* - This type typically shows **keratinization** and is usually located in **peripheral lung fields**, contrasting with the **central lung mass** observed here [2,5]. - It is more commonly associated with **cavitary lesions** and **hypercalcemia**, which are not present in this scenario [2]. *Adenocarcinoma* - Usually presents as a **peripheral lung mass** and is more prominent in **non-smokers**, which does not fit the profile of this patient [3]. - Biopsies typically show **glandular differentiation**, rather than the **small, round, blue cells** seen here. *Large cell carcinoma* - This variant often presents as a **large peripheral mass** and does not have the neuroendocrine features seen in this patient. - The histological findings do not match as it consists of **undifferentiated cells** that are larger, not small and blue. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Respiratory Tract Disease, pp. 337-338. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Respiratory Tract Disease, pp. 336-337. [3] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Respiratory Tract Disease, pp. 335-336. [4] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Lung, pp. 723-724.

Question 815: A 40-year-old man with a history of Barrett's esophagus presents with progressive dysphagia and weight loss. A biopsy reveals glandular structures invading the esophageal wall. Which genetic mutation is most likely responsible for this lesion?

A. APC
B. KRAS
C. TP53 (Correct Answer)
D. EGFR

Explanation: **TP53** - A history of **Barrett's esophagus** with progression to dysphagia, weight loss, and glandular invasion points to **esophageal adenocarcinoma** [1]. - **TP53 mutations** are commonly found in the progression from metaplasia in Barrett's esophagus to **dysplasia** and subsequent **adenocarcinoma**, indicating genomic instability. *APC* - **APC (adenomatous polyposis coli)** gene mutations are most frequently associated with **colorectal cancer**, particularly in familial adenomatous polyposis. - While fundamental in cell growth regulation, mutations in APC are not typically the primary drivers of esophageal adenocarcinoma. *KRAS* - **KRAS mutations** are prominent in several cancers, including **pancreatic cancer**, **non-small cell lung cancer**, and **colorectal cancer**. - While some gastrointestinal cancers may involve KRAS, it is not as frequently implicated in the progression of Barrett's esophagus to adenocarcinoma as TP53. *EGFR* - **EGFR (epidermal growth factor receptor)** mutations are particularly relevant in **non-small cell lung cancer** and some head and neck squamous cell carcinomas. - They are less commonly identified as a primary driver mutation in the development and progression of esophageal adenocarcinoma. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Gastrointestinal Tract, pp. 764-766.

Question 816: What is the most common type of benign tumor in the parotid gland?

A. Warthin's tumor
B. Pleomorphic adenoma (Correct Answer)
C. Adenoid cystic carcinoma
D. Oncocytoma

Explanation: ***Pleomorphic adenoma*** - This is the **most common benign tumor** of the salivary glands, particularly the parotid gland, accounting for 60-70% of all parotid tumors [1]. - It is characterized by its **mixed histological appearance**, containing both epithelial and mesenchymal components [1]. *Warthin's tumor* - This is the **second most common benign parotid tumor**, frequently affecting older men and smokers [1]. - It has a characteristic histological appearance with **cystic spaces, papillary projections, and lymphoid stroma** [1]. *Adenoid cystic carcinoma* - This is a **malignant tumor**, not benign, known for its slow growth but high propensity for **perineural invasion** and recurrence [1]. - It typically presents with pain and sometimes facial nerve paralysis due to its aggressive infiltrative nature. *Oncocytoma* - Oncocytomas are **rare benign tumors** composed of oncocytes, which are large epithelial cells with abundant eosinophilic granular cytoplasm. - They are much less common than pleomorphic adenomas or Warthin's tumors in the parotid gland. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Head and Neck, pp. 751-755.

Question 817: A patient with chronic hepatitis B presents with fatigue and abdominal pain. What is the primary mechanism by which hepatitis B increases the risk of hepatocellular carcinoma?

A. Direct mutagenesis by viral DNA integration (Correct Answer)
B. Immunosuppression leading to secondary infections
C. Inhibition of hepatic cytokine signaling
D. Stimulation of liver regeneration

Explanation: ***Direct mutagenesis by viral DNA integration*** - Hepatitis B virus can integrate its **viral DNA** into the host genome, which may lead to **mutations** and genomic instability in liver cells [1]. - This integration disrupts normal cellular functions and promotes **malignant transformation**, increasing the risk of hepatocellular carcinoma [1]. - The HBx protein is necessary for virus replication and has been implicated in the pathogenesis of hepatocellular carcinoma through transcriptional transactivation of viral and host genes [2]. *Stimulation of liver regeneration* - While chronic inflammation can trigger **liver regeneration**, excessive regeneration itself does not directly cause **carcinogenesis**. - The risk of cancer is related to the **genetic alteration** from viral infection, not merely from the regenerative response. *Inhibition of hepatic cytokine signaling* - This could affect the immune response but does not specifically explain the **increased oncogenic risks** associated with hepatitis B infection. - The mechanism involves direct **viral interactions** rather than mere cytokine modulation. *Immunosuppression leading to secondary infections* - Although immunosuppression can lead to increased susceptibility to infections, it is **not the primary mechanism** of carcinogenesis in chronic hepatitis B. - The risk arises from mutations and abnormal cellular growth due to direct **viral effects**, not just opportunistic infections. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Neoplasia, pp. 336-337. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Liver and Gallbladder, pp. 838-840.

Question 818: Von Hippel-Lindau syndrome is associated with which type of renal neoplasm?

A. Renal clear cell carcinoma (Correct Answer)
B. Transitional cell carcinoma
C. Wilms tumor
D. Renal oncocytoma

Explanation: ***Renal clear cell carcinoma*** - **Von Hippel-Lindau (VHL) syndrome** is strongly associated with the development of **renal clear cell carcinoma**, often manifesting as multiple or bilateral tumors [2]. - The VHL gene is a **tumor suppressor gene**, and its inactivation in VHL syndrome predisposes to the growth of various tumors, including clear cell renal carcinomas [2]. *Transitional cell carcinoma* - This type of carcinoma originates from the **urothelium** lining the renal pelvis, ureters, or bladder, and is not directly associated with VHL syndrome. - Risk factors for transitional cell carcinoma often include **smoking** and exposure to certain industrial chemicals. *Wilms tumor* - **Wilms tumor (nephroblastoma)** is a childhood kidney cancer, typically presenting before the age of 5. - It is associated with mutations in the **WT1 gene** and other genetic syndromes like WAGR syndrome and Denys-Drash syndrome, not VHL syndrome. *Renal oncocytoma* - **Renal oncocytomas** are benign epithelial tumors of the kidney, characterized by eosinophilic granular cells [1]. - While they can mimic renal cell carcinoma on imaging, they are generally not associated with VHL syndrome [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Kidney, p. 959. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Kidney, pp. 959-961.

Question 819: A 40-year-old female presents with a mass in her neck. Fine-needle aspiration reveals medullary thyroid carcinoma. Which genetic mutation is most commonly associated with this condition?

A. BRAF
B. RET (Correct Answer)
C. RAS
D. P53

Explanation: ***RET*** - **Medullary thyroid carcinoma (MTC)** is almost invariably associated with mutations in the **RET proto-oncogene**. - These mutations can be *germline* (hereditary MTC, often part of **Multiple Endocrine Neoplasia type 2 - MEN2**) or *somatic* (sporadic MTC). *BRAF* - **BRAF mutations**, particularly the V600E variant, are the most common genetic alterations found in **papillary thyroid carcinoma**, not medullary. - Tumors with BRAF mutations tend to be more aggressive and are less likely to respond to radioactive iodine therapy. *RAS* - **RAS mutations** (HRAS, KRAS, NRAS) are commonly found in **follicular thyroid carcinoma** and some cases of papillary thyroid carcinoma. - While they contribute to cell proliferation and differentiation, they are not the primary driver in medullary thyroid carcinoma. *P53* - **TP53 mutations** are rare in differentiated thyroid cancers but are frequently seen in **anaplastic thyroid carcinoma**, a highly aggressive and undifferentiated form. - P53 is a tumor suppressor gene, and its inactivation leads to uncontrolled cell growth and reduced apoptosis.

Question 820: A biopsy from a breast lump shows small, uniform cells that are estrogen receptor positive. This finding is most consistent with which type of breast cancer?

A. Ductal carcinoma in situ
B. Lobular carcinoma (Correct Answer)
C. Inflammatory breast cancer
D. Triple-negative breast cancer

Explanation: ***Lobular carcinoma*** - Characterized by **small, uniform cells** that are often estrogen receptor positive, aligning with the biopsy findings [1]. - Typically, **invasive lobular carcinoma** may present with subtle features and often leads to bilateral involvement. *Triple-negative breast cancer* - Defined by the absence of **estrogen receptors**, **progesterone receptors**, and **HER2/neu**, which contradicts the positive estrogen receptor finding. - Often associated with **high histological grade** and a more aggressive behavior compared to other types. *Ductal carcinoma in situ* - Although it can show **positive estrogen receptors**, it is primarily characterized by **ductal involvement** without invasion into surrounding tissue. - Typically presents with **calcifications** on mammography rather than the solid tumor appearance noted in this biopsy. *Inflammatory breast cancer* - Features **cutaneous changes** and **lymphedema** rather than small, uniform cells; it causes a more aggressive and diffuse breast distortion. - Rarely presents with estrogen receptor positivity, particularly when compared to lobular carcinoma's characteristics. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Breast, pp. 1068-1069.

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Neoplasia — MCQs

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