Neuroendocrine Tumors — MCQs
VIPoma is associated with which syndrome?
A 40-year-old man has hemoptysis. CXR shows a coin lesion. Biopsy reveals nests of neuroendocrine cells with salt-and-pepper chromatin. What is the most likely diagnosis?
A 35-year-old woman presents with 6-month history of skin rash and fatigue. Physical examination shows pallor and a necrotizing erythematous skin rash of her lower body. Laboratory studies reveal mild anemia and fasting blood glucose of 160 mg/dL. A CT scan of the abdomen demonstrates a 2-cm mass in the pancreas. Which of the following is the most likely diagnosis?
Most common site for carcinoid tumor in the abdomen is which of the following?
Marker for pancreatic non-functional neuro-endocrine tumor is
Most of the parotid tumors are managed by:
What is the initial treatment for most patients with growth hormone-secreting pituitary adenoma?
What is the imaging modality of choice for localizing neuroendocrine tumors?
What is the appropriate management for a patient with a carcinoid tumor of the appendix larger than 2 cm?
A 45-year-old man presents with an upper gastrointestinal bleed. An upper endoscopy reveals multiple duodenal ulcers and an enlarged stomach.
Neuroendocrine Tumors Indian Medical PG Practice Questions and MCQs
Question 1: VIPoma is associated with which syndrome?
- A. Cushing's syndrome
- B. Verner-Morrison syndrome (Correct Answer)
- C. Carcinoid syndrome (serotonin syndrome)
- D. Zollinger-Ellison syndrome
Explanation: ***Verner-Morrison syndrome*** - **VIPoma** is a neuroendocrine tumor that secretes **vasoactive intestinal peptide (VIP)**, causing symptoms like watery diarrhea, hypokalemia, and achlorhydria (WDHA syndrome) [1]. - This clinical presentation is also known as **Verner-Morrison syndrome**, directly linking the VIPoma to this syndrome [1]. *Cushing's syndrome* - Characterized by excessive **cortisol** production, leading to symptoms like central obesity, moon facies, and hypertension [3]. - This syndrome is not directly associated with VIP excess or the watery diarrhea seen in VIPoma [2]. *Carcinoid syndrome (serotonin syndrome)* - Caused by tumors, typically in the gastrointestinal tract, that produce **serotonin**, leading to flushing, diarrhea, and bronchospasm [1]. - While it involves diarrhea, the primary mediator is serotonin, not VIP, and the other classic VIPoma symptoms (hypokalemia, achlorhydria) are absent [1]. *Zollinger-Ellison syndrome* - Characterized by a **gastrin-producing tumor (gastrinoma)**, which causes excessive gastric acid secretion and severe peptic ulcer disease [4]. - The hormonal excess is **gastrin**, not VIP, and symptoms are related to acid overproduction rather than massive watery diarrhea and hypokalemia [4].
Question 2: A 40-year-old man has hemoptysis. CXR shows a coin lesion. Biopsy reveals nests of neuroendocrine cells with salt-and-pepper chromatin. What is the most likely diagnosis?
- A. Squamous cell carcinoma
- B. Carcinoid tumor (Correct Answer)
- C. Adenocarcinoma
- D. Small cell carcinoma
Explanation: ***Carcinoid tumor*** - **Nests of neuroendocrine cells** with **salt-and-pepper chromatin** are classic histological features of a carcinoid tumor. - While presented as a **coin lesion** (solitary pulmonary nodule) [2], this type of neuroendocrine tumor typically has a more indolent course compared to other lung malignancies. *Squamous cell carcinoma* - Characterized by **keratinization** and **intercellular bridges**, not neuroendocrine differentiation. - Often presents as a **central mass** with cavitation and is strongly associated with smoking [1]. *Adenocarcinoma* - Grows in glandular patterns and produces **mucin**, usually found in the periphery of the lung. - Lacks the neuroendocrine features of salt-and-pepper chromatin or rosette formation. *Small cell carcinoma* - Consists of small, undifferentiated cells with **scant cytoplasm** and **absent nucleoli**, known for rapid growth. - Although also neuroendocrine, it presents with a much more aggressive clinical course and characteristic **oat cell morphology**, distinct from the well-differentiated nests seen in carcinoid.
Question 3: A 35-year-old woman presents with 6-month history of skin rash and fatigue. Physical examination shows pallor and a necrotizing erythematous skin rash of her lower body. Laboratory studies reveal mild anemia and fasting blood glucose of 160 mg/dL. A CT scan of the abdomen demonstrates a 2-cm mass in the pancreas. Which of the following is the most likely diagnosis?
- A. Insulinoma
- B. Glucagonoma (Correct Answer)
- C. Gastrinoma
- D. Carcinoid tumor
Explanation: ***Glucagonoma*** - The necrotizing erythematous skin rash (necrolytic migratory erythema), mild anemia, hyperglycemia (fasting blood glucose 160 mg/dL), and a pancreatic mass are classic features of a **glucagonoma**. [1] - **Glucagon** excess leads to skin rash, glucose intolerance due to its counter-regulatory effects on insulin, and often anemia. [1] *Insulinoma* - An insulinoma typically presents with symptoms of **hypoglycemia** (e.g., sweating, palpitations, confusion), especially in the fasting state. [2] - While it involves a pancreatic mass, the patient's hyperglycemia and specific skin rash are inconsistent with insulinoma. [2] *Gastrinoma* - Gastrinomas cause **Zollinger-Ellison syndrome**, characterized by severe peptic ulcer disease, abdominal pain, and diarrhea due to excessive **gastrin** production. [1] - The patient's symptoms, particularly the skin rash and hyperglycemia, are not typical of a gastrinoma. *Carcinoid tumor* - Carcinoid tumors can arise in various locations, including the pancreas, but typically produce **serotonin** and other vasoactive substances. [1] - Symptoms usually include **flushing**, diarrhea, and bronchospasm (carcinoid syndrome), which are absent in this patient's presentation. [1]
Question 4: Most common site for carcinoid tumor in the abdomen is which of the following?
- A. Liver
- B. Pancreas
- C. Appendix (Correct Answer)
- D. Intestines
Explanation: ***Appendix*** - The **appendix** is the most common site for carcinoid tumors in the abdomen, accounting for approximately **35-40%** of all gastrointestinal carcinoid tumors. - These tumors are typically **small (<1 cm)**, found **incidentally** during appendectomy, and have an **excellent prognosis**. - Most appendiceal carcinoids are located at the **tip of the appendix** and rarely metastasize when small. *Intestines (Small Intestine)* - The small intestine, particularly the **ileum**, is the second most common site, accounting for **20-30%** of GI carcinoids. - Small intestinal carcinoids are more **clinically significant** as they are more likely to be **larger**, **symptomatic**, and cause **metastasis**. - These are more commonly associated with **carcinoid syndrome** due to their higher metastatic potential. *Liver* - The liver is the most common site for **metastasis** from carcinoid tumors but is **rarely a primary site**. - Liver metastases allow hormones to bypass hepatic first-pass metabolism, leading to **carcinoid syndrome** (flushing, diarrhea, bronchospasm). *Pancreas* - Pancreatic neuroendocrine tumors (PNETs) are a distinct subgroup but are **less common** than appendiceal or small intestinal carcinoids. - PNETs can be **functional** (insulinoma, gastrinoma, VIPoma) or **non-functional**, with varying clinical presentations.
Question 5: Marker for pancreatic non-functional neuro-endocrine tumor is
- A. CEA
- B. PSA
- C. CD100
- D. Chromogranin-A (Correct Answer)
Explanation: ***Chromogranin-A*** - **Chromogranin-A** is a glycoprotein found in the neurosecretory granules of various neuroendocrine cells, making it a reliable **general neuroendocrine tumor marker** [1]. - Elevated levels are particularly useful for detecting and monitoring **pancreatic non-functional neuroendocrine tumors**, which often lack specific hormonal symptoms. *CEA* - **Carcinoembryonic antigen (CEA)** is primarily used as a tumor marker for **colorectal cancer**, and less commonly for other adenocarcinomas like pancreatic adenocarcinoma. - It is generally **not a specific marker** for neuroendocrine tumors. *PSA* - **Prostate-specific antigen (PSA)** is a specific marker for **prostate cancer**, used for screening, diagnosis, and monitoring of this particular malignancy. - It has **no relevance** in the diagnosis or monitoring of pancreatic neuroendocrine tumors. *CD100* - **CD100** (also known as semaphorin-4D) is a membrane glycoprotein involved in immune cell regulation and has been implicated in certain cancers, such as those of **hematopoietic origin**. - It is **not used as a marker** for pancreatic non-functional neuroendocrine tumors. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Gastrointestinal Tract, pp. 780-781.
Question 6: Most of the parotid tumors are managed by:
- A. Total parotidectomy
- B. Radical parotidectomy & Neck dissection
- C. Superficial parotidectomy (Correct Answer)
- D. Radical parotidectomy
Explanation: ***Superficial parotidectomy*** - The vast majority of parotid tumors, especially **benign tumors** like **pleomorphic adenomas**, arise in the **superficial lobe** of the parotid gland. - This procedure removes the superficial lobe while preserving the **facial nerve**, which is crucial for facial expression. - **Most common procedure** for parotid tumors since 80-85% are benign and superficial. *Total parotidectomy* - This procedure removes both the **superficial and deep lobes** of the parotid gland. - Typically reserved for tumors affecting the **deep lobe** or those with extensive involvement. - Less common than superficial parotidectomy as deep lobe tumors are uncommon. *Radical parotidectomy & Neck dissection* - **Radical parotidectomy** involves removing the entire parotid gland, often sacrificing the **facial nerve**, and a **neck dissection** removes lymph nodes in the neck. - This aggressive approach is reserved for **malignant tumors** with known or suspected **nodal metastasis**. - Represents a small percentage of parotid tumor cases. *Radical parotidectomy* - This procedure involves removal of the entire parotid gland, often including the **facial nerve** or its branches, due to tumor infiltration. - Indicated for **high-grade malignant tumors** with nerve involvement but without overt nodal metastasis. - Less common than benign superficial tumors requiring only superficial parotidectomy.
Question 7: What is the initial treatment for most patients with growth hormone-secreting pituitary adenoma?
- A. Transphenoidal surgical resection (Correct Answer)
- B. Somatostatin analogs
- C. Dopamine agonists
- D. GH receptor antagonists
Explanation: ***Transphenoidal surgical resection*** - This is the **preferred initial treatment** for most growth hormone (GH)-secreting pituitary adenomas, as it offers the best chance for **cure** and rapid reduction in GH levels [1]. - Success rates are high, especially for **smaller tumors** (microadenomas), and it can quickly relieve mass effect symptoms [1]. *Somatostatin analogs* - These are typically used as **second-line therapy** if surgery is unsuccessful or contraindicated, or in patients not surgical candidates. - They work by **inhibiting GH secretion** but do not usually achieve a complete cure like surgery. *GH receptor antagonists* - These medications, such as pegvisomant, **block the action of GH** at its receptor, normalizing IGF-1 levels. - They are primarily used when other treatments, including surgery and somatostatin analogs, have failed to control GH excess. *Dopamine agonists* - While dopamine agonists (e.g., cabergoline) can **sometimes reduce GH secretion** in a minority of patients, they are significantly less effective for GH-secreting tumors compared to prolactinomas [1]. - They are occasionally used as **adjunctive therapy** or in specific cases where the GH-secreting tumor also co-secretes prolactin [1].
Question 8: What is the imaging modality of choice for localizing neuroendocrine tumors?
- A. USG
- B. CT
- C. MRI
- D. Somatostatin receptor scintigraphy (Correct Answer)
Explanation: ***Somatostatin receptor scintigraphy*** - **Somatostatin receptor scintigraphy** is the imaging modality of choice given that most neuroendocrine tumors (NETs) express a high density of somatostatin receptors. - **68Ga-DOTATATE PET/CT** is the **current preferred technique**, offering superior sensitivity (>90%) and specificity compared to older methods like Indium-111 pentetreotide (Octreoscan). - This functional imaging allows for **whole-body evaluation** and can detect both primary tumors and metastases, including small lesions that may be missed on conventional anatomical imaging. - Particularly valuable for detecting occult primary tumors and staging metastatic disease. *USG* - **Ultrasound** is useful for initial screening or evaluating superficial NETs, particularly in organs like the pancreas or liver. - However, its utility is limited by **operator dependence**, gas artifact, and its inability to detect small or deeply located tumors effectively. - Does not provide functional information about somatostatin receptor expression. *CT* - **Computed tomography** provides good anatomical detail and is useful for assessing tumor size, local invasion, and detecting liver metastases. - While helpful for anatomical characterization, CT can **miss small lesions** (especially <1 cm) and does not provide functional information about receptor status. - Often used in combination with functional imaging for treatment planning. *MRI* - **Magnetic resonance imaging** offers excellent soft tissue contrast and is particularly useful for NETs in the liver and pancreas. - Superior to CT for detecting liver metastases due to better soft tissue resolution. - However, MRI has **lower sensitivity for small or widespread lesions** compared to somatostatin receptor imaging and does not provide functional receptor information.
Question 9: What is the appropriate management for a patient with a carcinoid tumor of the appendix larger than 2 cm?
- A. Right hemicolectomy (Correct Answer)
- B. Appendicectomy
- C. Appendicectomy + abdominal CT scan
- D. Appendicectomy + 24 hrs urinary HIAA
Explanation: ***Right hemicolectomy*** - Carcinoid tumors of the appendix larger than **2 cm** are considered at high risk for **lymph node metastasis** and recurrence. - A **right hemicolectomy** provides adequate margins and allows for lymph node dissection, which is essential for staging and definitive treatment in such cases. *Appendicectomy* - An **appendicectomy** alone is typically sufficient for carcinoid tumors of the appendix that are **less than 1 cm** and localized to the tip. - For larger tumors, appendicectomy carries an unacceptably high risk of **incomplete resection** and metastatic disease. *Appendicectomy + abdominal CT scan* - While an **abdominal CT scan** is useful for assessing local spread and distant metastases, it does not address the need for a more extensive surgical resection for a **large primary tumor**. - A simple **appendicectomy** in this scenario would be inadequate as definitive treatment. *Appendicectomy + 24 hrs urinary HIAA* - **24-hour urinary 5-hydroxyindoleacetic acid (5-HIAA)** is a biomarker used to detect and monitor **carcinoid syndrome**, which occurs in a minority of patients with carcinoid tumors. - Measuring 5-HIAA is primarily for assessing systemic symptoms rather than determining the primary surgical management of the **tumor size**.
Question 10: A 45-year-old man presents with an upper gastrointestinal bleed. An upper endoscopy reveals multiple duodenal ulcers and an enlarged stomach.
- A. Insulinoma
- B. Zollinger-Ellison syndrome (ZES) (Correct Answer)
- C. Glucagonoma
- D. Watery diarrhea, hypokalemia, and achlorhydria (WDHA) syndrome
Explanation: ***Zollinger-Ellison syndrome (ZES)*** - **ZES** is characterized by excessive **gastrin** secretion, leading to multiple, refractory peptic ulcers, especially in the **duodenum**, and often an **enlarged stomach** due to gastric hyperplasia [1]. - The combination of **multiple duodenal ulcers** and an **upper gastrointestinal bleed** strongly suggests this diagnosis [1]. *Glucagonoma* - Characterized by a **necrolytic migratory erythema** rash, stomatitis, and diabetes, which are not present here. - Does not typically cause **multiple duodenal ulcers** or an **enlarged stomach**. *Insulinoma* - Presents with symptoms of **hypoglycemia** such as sweating, tremors, and confusion, which are absent in this case. - Does not cause **gastric hyperplasia** or **recurrent peptic ulcers**. *Watery diarrhea, hypokalemia, and achlorhydria (WDHA) syndrome* - Primarily presents with **severe watery diarrhea**, **hypokalemia**, and **achlorhydria** due to VIPoma (vasoactive intestinal peptide-secreting tumor). - This syndrome does not typically cause **gastrointestinal bleeding** or **duodenal ulcers**.
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