Adrenal Incidentalomas — MCQs
VMA is elevated in which of the following condition?
In a patient diagnosed with pheochromocytoma, what is the appropriate preoperative pharmacological management to control hypertension before surgery?
What is the correct sequence of medication administration for pre-operative prophylaxis in pheochromocytoma?
What is the most common adrenal incidentaloma?
Investigation of choice in pheochromocytoma is:
Where is a bruit typically heard in the thyroid gland?
Which of the following statements is FALSE regarding medullary cancer of the thyroid?
Which type of thyroid carcinoma is associated with hypocalcemia?
A patient presents with secondary adrenal masses. What is the most common primary site for such metastases?
Which of the following statements is not true regarding medullary thyroid carcinoma?
Adrenal Incidentalomas Indian Medical PG Practice Questions and MCQs
Question 1: VMA is elevated in which of the following condition?
- A. Tuberous sclerosis
- B. Addison disease
- C. Pheochromocytoma (Correct Answer)
- D. Conn Syndrome
Explanation: Pheochromocytoma - Pheochromocytoma is a tumor of the adrenal medulla that secretes excessive amounts of catecholamines (epinephrine and norepinephrine). - Vanillylmandelic acid (VMA) is a breakdown product of these catecholamines [1], so its levels are elevated in the urine of patients with pheochromocytoma. Tuberous sclerosis - Tuberous sclerosis is a genetic disorder characterized by the growth of numerous non-cancerous tumors in various organs. - While it can be associated with renal angiomyolipomas or brain lesions, it does not directly cause elevated VMA levels. Addison disease - Addison disease is characterized by adrenal insufficiency [2], meaning the adrenal glands produce insufficient amounts of hormones like cortisol and aldosterone. - This condition is not associated with the overproduction of catecholamines or elevated VMA. Conn Syndrome - Conn syndrome (primary hyperaldosteronism) is due to an overproduction of aldosterone by the adrenal glands, often caused by an adrenal adenoma [3]. - Aldosterone is a mineralocorticoid, and its overproduction does not lead to increased catecholamine metabolism or elevated VMA levels.
Question 2: In a patient diagnosed with pheochromocytoma, what is the appropriate preoperative pharmacological management to control hypertension before surgery?
- A. Phenoxybenzamine and propranolol (Correct Answer)
- B. Propranolol
- C. Nitroglycerine
- D. Phentolamine
Explanation: ***Phenoxybenzamine and propranolol*** - **Phenoxybenzamine** (an **irreversible** non-selective **alpha-blocker**) is initiated first to prevent hypertensive crises during surgery by blocking the effects of catecholamines on blood vessels. - **Propranolol** (a **beta-blocker**) is added after adequate alpha-blockade to control **tachycardia** and arrhythmias, as blocking only alpha-receptors can lead to unopposed beta-adrenergic stimulation. *Phentolamine (short-acting alpha blocker)* - While **phentolamine** is an alpha-blocker, it is typically used for **intraoperative management** of hypertensive crises or for short-term control, not as the primary preoperative preparation. - It is a **reversible** blocker and does not provide the sustained, robust alpha-blockade required for safe preoperative management of pheochromocytoma. *Propranolol (beta-blocker)* - **Beta-blockers** alone should **never be started first** in pheochromocytoma because blocking beta-2 receptors (which mediate vasodilation) in the presence of high circulating catecholamines can lead to **unopposed alpha-adrenergic vasoconstriction**, causing a dangerous hypertensive crisis. - It is only added after adequate alpha-blockade has been achieved to manage **tachycardia**. *Nitroglycerine (vasodilator)* - **Nitroglycerine** is primarily a **venodilator** and is used to relieve angina or manage acute hypertensive emergencies, not for the chronic preoperative management of pheochromocytoma. - It does not address the underlying pathophysiology of excessive catecholamine release and can lead to reflex **tachycardia**.
Question 3: What is the correct sequence of medication administration for pre-operative prophylaxis in pheochromocytoma?
- A. Beta blockade followed by alpha blockade
- B. Simultaneous alpha and beta blockade
- C. Alpha blockade followed by beta blockade (Correct Answer)
- D. Alpha blockade only
Explanation: ***Alpha blockade followed by beta blockade*** - **Alpha blockade** should always be initiated first to control **hypertension** and prevent a **hypertensive crisis** during surgery. This is critical because pheochromocytoma causes excessive catecholamine release, leading to profound vasoconstriction. - **Beta blockade** is then added only after adequate alpha blockade has been achieved to control **tachycardia** and arrhythmias, preventing **unopposed alpha-adrenergic stimulation** which could paradoxically worsen hypertension. *Simultaneous alpha and beta blockade* - Administering both simultaneously is dangerous because **beta blockade** can mask the effects of inadequate alpha blockade. - This can lead to **unopposed alpha-adrenergic stimulation** after beta blockade, causing severe **vasoconstriction** and hypertensive crisis. *Beta blockade followed by alpha blockade* - Initiating with **beta blockade** without prior **alpha blockade** is absolutely contraindicated in pheochromocytoma. - This can lead to severe and potentially fatal **hypertension** due to **unopposed alpha-adrenergic stimulation** as beta blockade prevents vasodilation. *Alpha blockade only* - While essential for initial management, **alpha blockade alone** might not fully control all symptoms, especially **tachycardia** and **arrhythmias** caused by high circulating catecholamine levels. - Adding a **beta blocker** after achieving adequate alpha blockade helps in controlling these cardiac effects, optimizing patient preparation for surgery.
Question 4: What is the most common adrenal incidentaloma?
- A. Aldosterone producing
- B. Pheochromocytoma
- C. Endocrine inactive tumors (Correct Answer)
- D. Cortisol producing
Explanation: ***Endocrine inactive tumors*** - The majority, about **70-85%**, of adrenal incidentalomas are **benign, non-secretory adenomas**, which are often referred to as endocrine inactive tumors. [1] - These tumors do not produce excess hormones and are typically discovered incidentally on imaging performed for other reasons. *Cortisol producing* - While **cortisol-producing adenomas** are a type of functional adrenal tumor, they represent a smaller percentage of incidentalomas, usually less than 10%. - These can lead to **Cushing's syndrome**, but most incidentalomas causing hypercortisolism are subclinical. *Aldosterone producing* - **Aldosterone-producing adenomas**, which cause primary aldosteronism, are also less common than inactive tumors, accounting for about 1-5% of incidentalomas. [1] - They are typically associated with **hypertension** and **hypokalemia**. *Pheochromocytoma* - **Pheochromocytomas**, which secrete catecholamines, are rare adrenal incidentalomas, making up less than 5% of cases. - These tumors can cause **hypertension**, **tachycardia**, and other symptoms related to catecholamine excess. [1]
Question 5: Investigation of choice in pheochromocytoma is:
- A. CT scan
- B. Urinary catecholamines (Correct Answer)
- C. MIBG scan
- D. MRI Scan
Explanation: ***Urinary catecholamines*** - Measurement of **24-hour urinary fractionated metanephrines and catecholamines** is the initial **biochemical test of choice**. - These biochemical tests are preferred over plasma levels due to the **episodic release** of hormones from a pheochromocytoma, which can lead to high false-negative rates in single plasma measurements. *CT scan* - While a **CT scan** is a crucial **imaging modality** for localizing a pheochromocytoma once the biochemical diagnosis is established [1], it is not the *initial* diagnostic investigation. - Imaging should be performed only after **biochemical confirmation** to avoid unnecessary investigations of incidental adrenal masses [1]. *MIBG scan* - An **MIBG scan** (metaiodobenzylguanidine scan) is a **functional imaging study** used primarily for **localizing metastatic pheochromocytomas** [1] or for cases where CT/MRI is equivocal. - It is not the initial investigation but rather a **secondary imaging test** [1]. *MRI Scan* - **MRI** is an alternative **imaging modality** to CT for localizing pheochromocytomas [1], especially in pregnant women or when radiation exposure is a concern. - Like CT, it serves as a **localization tool** after biochemical confirmation, not the diagnostic test itself.
Question 6: Where is a bruit typically heard in the thyroid gland?
- A. Upper pole (Correct Answer)
- B. Lower pole
- C. Middle part
- D. Lateral aspect
Explanation: **Explanation:** The presence of a thyroid bruit is a classic clinical sign of **Graves' disease** (toxic diffuse goiter). It occurs due to the hyperdynamic circulation and significantly increased vascularity of the gland. **Why the Upper Pole is Correct:** The bruit is most commonly heard over the **upper pole** of the thyroid gland. This is because the **superior thyroid artery**, a direct branch of the external carotid artery, enters the gland at the upper pole. Due to its proximity to a major high-pressure arterial trunk and its relatively superficial location, the turbulent blood flow (hypervascularity) is most audible at this site. **Analysis of Incorrect Options:** * **Lower Pole:** While the inferior thyroid artery (from the thyrocervical trunk) supplies the lower pole, it is situated deeper and has a more tortuous course, making a bruit less likely to be localized here compared to the superior pole. * **Middle Part & Lateral Aspect:** These areas represent the body of the lobes. While vascularity is increased throughout in Graves' disease, the primary inflow points (the poles) are the high-yield areas for auscultation. **High-Yield Clinical Pearls for NEET-PG:** 1. **Bruit vs. Thrill:** A bruit is an auditory sign (auscultation), whereas a **thrill** is its tactile equivalent (palpation). Both indicate Graves' disease. 2. **Differential Diagnosis:** A thyroid bruit must be distinguished from a **venous hum** (disappears with pressure over the internal jugular vein) and a **carotid bruit** (heard lateral to the gland). 3. **Significance:** The presence of a bruit is highly specific for Graves' disease and helps differentiate it from other causes of thyrotoxicosis, such as toxic multinodular goiter or thyroiditis.
Question 7: Which of the following statements is FALSE regarding medullary cancer of the thyroid?
- A. Secrete Calcitonin
- B. 20-25% are familial
- C. Diarrhea is seen in 30%
- D. These cancers take up Radioactive Iodine (Correct Answer)
Explanation: ### Explanation **Medullary Thyroid Carcinoma (MTC)** arises from the **parafollicular C-cells**, which are neuroendocrine cells derived from the neural crest. This fundamental embryological origin is the key to understanding its clinical behavior and management. **Why Option D is the Correct (False) Statement:** Radioactive Iodine (RAI) uptake depends on the expression of the Sodium-Iodide Symporter (NIS), which is exclusive to follicular epithelial cells. Since MTC originates from C-cells (not follicular cells), these tumors **do not take up radioactive iodine**. Consequently, RAI ablation is not a therapeutic option for MTC, unlike papillary or follicular thyroid cancers. **Analysis of Other Options:** * **Option A (True):** C-cells naturally produce **Calcitonin**. Elevated serum calcitonin is a highly sensitive and specific tumor marker for MTC, used for both diagnosis and monitoring recurrence. * **Option B (True):** Approximately **20–25%** of MTC cases are familial, occurring as part of **MEN 2A, MEN 2B**, or Familial MTC (FMTC) syndromes, usually due to germline **RET proto-oncogene** mutations. The remaining 75–80% are sporadic. * **Option C (True):** Diarrhea occurs in about **30%** of patients, particularly in advanced or metastatic disease. It is caused by the hypersecretion of calcitonin, prostaglandins, or serotonin, which increases intestinal motility. **High-Yield Clinical Pearls for NEET-PG:** * **Amyloid Stroma:** Histologically, MTC is characterized by nests of cells separated by amyloid deposits (stained by Congo Red). * **CEA:** Carcinoembryonic Antigen is another important tumor marker for MTC. * **Screening:** All patients diagnosed with MTC must be screened for **RET mutations** and **Pheochromocytoma** (before surgery) to rule out MEN 2. * **Treatment:** The primary treatment is Total Thyroidectomy with central compartment neck dissection.
Question 8: Which type of thyroid carcinoma is associated with hypocalcemia?
- A. Follicular carcinoma
- B. Medullary carcinoma (Correct Answer)
- C. Anaplastic carcinoma
- D. Papillary carcinoma
Explanation: **Explanation:** **Medullary Thyroid Carcinoma (MTC)** is the correct answer because of its unique cellular origin. Unlike other thyroid cancers that arise from follicular cells, MTC originates from the **Parafollicular C-cells** of the thyroid gland. These cells are responsible for the secretion of **Calcitonin**. In MTC, there is a pathological hypersecretion of Calcitonin. Calcitonin acts as a physiological antagonist to Parathyroid Hormone (PTH); it lowers serum calcium levels by inhibiting bone resorption (osteoclast activity) and increasing renal calcium excretion. While clinical hypocalcemia is rare in MTC patients due to compensatory mechanisms, the biochemical association with calcium-lowering hormones makes it the characteristic answer for this question. **Why other options are incorrect:** * **Papillary and Follicular Carcinoma:** These are "Differentiated Thyroid Cancers" (DTC) arising from follicular cells. They secrete Thyroglobulin, not Calcitonin, and have no direct effect on calcium metabolism. * **Anaplastic Carcinoma:** This is an undifferentiated, highly aggressive tumor. While it can cause local invasion (leading to hoarseness or dysphagia), it does not produce hormones that regulate calcium. **High-Yield Clinical Pearls for NEET-PG:** * **Tumor Marker:** Calcitonin is used for both diagnosis and monitoring recurrence in MTC. Carcinoembryonic Antigen (CEA) is also often elevated. * **Genetics:** Approximately 25% of MTC cases are familial, associated with **MEN 2A and 2B** syndromes (RET proto-oncogene mutation). * **Amyloid Stroma:** Histologically, MTC is characterized by polygonal cells with **amyloid deposits** (derived from pro-calcitonin) that stain with Congo Red. * **Spread:** MTC spreads via both lymphatic and hematogenous routes.
Question 9: A patient presents with secondary adrenal masses. What is the most common primary site for such metastases?
- A. Lung (Correct Answer)
- B. Kidney
- C. Breast
- D. Stomach
Explanation: **Explanation:** The adrenal glands are a highly vascularized site, making them the fourth most common site for hematogenous metastasis in the body (after the liver, lungs, and bones). **1. Why Lung is Correct:** **Lung cancer** is the most common primary malignancy to metastasize to the adrenal glands. Approximately 30-40% of patients with lung cancer will have adrenal involvement at the time of autopsy. Both Small Cell Lung Cancer (SCLC) and Non-Small Cell Lung Cancer (NSCLC), particularly **adenocarcinoma**, frequently spread to the adrenals. In clinical practice, when a unilateral or bilateral adrenal mass is found in a patient with a history of smoking or respiratory symptoms, lung cancer is the primary suspect. **2. Analysis of Incorrect Options:** * **Kidney (Renal Cell Carcinoma):** While RCC can spread to the adrenal gland (often via direct extension or venous routes), it is less common than lung-derived metastases. * **Breast:** Breast cancer is the second most common primary site for adrenal metastasis. While frequent, it statistically trails behind lung cancer. * **Stomach:** Gastrointestinal malignancies (Stomach, Colon) can metastasize to the adrenals, but they are significantly less common than thoracic or breast primaries. **3. Clinical Pearls for NEET-PG:** * **Bilateral Involvement:** Metastatic disease is the most common cause of bilateral adrenal masses. * **Imaging:** On CT, metastases typically show high unenhanced attenuation (>10 HU) and slow washout of contrast, unlike benign adenomas. * **Biopsy Rule:** Never perform a Fine Needle Aspiration (FNA) of an adrenal mass until **Pheochromocytoma** has been ruled out (via plasma/urine metanephrines) to avoid a life-threatening hypertensive crisis. * **Adrenal Insufficiency:** Clinical Addison’s disease is rare in metastasis unless >90% of both glands are destroyed.
Question 10: Which of the following statements is not true regarding medullary thyroid carcinoma?
- A. They are a type of neuroendocrine tumor.
- B. They are associated with MEN 2A and 2B syndromes.
- C. They comprise approximately 25% of all thyroid malignancies. (Correct Answer)
- D. Tumor cells may secrete serotonin, ACTH, and VIP.
Explanation: **Explanation** Medullary Thyroid Carcinoma (MTC) is a unique thyroid malignancy arising from the **parafollicular C-cells**, which are derived from the **neural crest**. **1. Why Option C is the correct answer (The False Statement):** MTC is relatively rare, accounting for only **5% to 8%** of all thyroid malignancies. The most common thyroid cancer is Papillary Thyroid Carcinoma (PTC), which comprises about 80–85%. Stating that MTC represents 25% is a significant overestimation. **2. Analysis of other options:** * **Option A (True):** Because they originate from neural crest cells and secrete hormones, they are classified as **neuroendocrine tumors**. * **Option B (True):** Approximately 25% of MTC cases are hereditary. It is a key component of **MEN 2A** (MTC, Pheochromocytoma, Hyperparathyroidism) and **MEN 2B** (MTC, Pheochromocytoma, Mucosal neuromas, Marfanoid habitus). * **Option D (True):** While Calcitonin is the primary marker, MTC cells are pluripotential and can secrete ectopic hormones like **Serotonin** (causing flushing/diarrhea), **ACTH** (causing Cushing’s syndrome), and **VIP**. **High-Yield Clinical Pearls for NEET-PG:** * **Biomarkers:** **Calcitonin** (used for diagnosis and monitoring recurrence) and **CEA**. * **Histology:** Characterized by **Amyloid stroma** (stained by Congo Red showing apple-green birefringence). * **Genetics:** Strongly associated with **RET proto-oncogene** mutations. Prophylactic thyroidectomy is indicated in carriers. * **Spread:** Unlike papillary CA (lymphatic) or follicular CA (hematogenous), MTC spreads via **both** lymphatic and hematogenous routes early. * **Management:** Total thyroidectomy with central compartment neck dissection is the treatment of choice; MTC does **not** respond to Radioiodine (I-131) therapy.
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