Endocrine Surgery — MCQs

Endocrine Surgery Indian Medical PG Practice Questions and MCQs

Question 71: Which of the following is NOT a true statement about papillary carcinoma?

A. Radiation is a risk factor.
B. It can be multifocal.
C. Hematogenous spread is common. (Correct Answer)
D. Distant metastasis is seen.

Explanation: **Explanation:** Papillary Thyroid Carcinoma (PTC) is the most common type of thyroid malignancy. The hallmark of PTC is its tendency for **lymphatic spread** rather than hematogenous spread. 1. **Why Option C is the correct (False) statement:** Unlike Follicular Thyroid Carcinoma, which characteristically spreads via the bloodstream (hematogenous), Papillary Carcinoma primarily spreads through the lymphatics to the cervical lymph nodes. While hematogenous spread can occur, it is **uncommon** (occurring in <5-10% of cases). Therefore, stating it is "common" is incorrect. 2. **Analysis of other options:** * **Option A (Radiation):** Exposure to ionizing radiation (especially during childhood) is the most well-established environmental risk factor for PTC. * **Option B (Multifocal):** PTC is frequently multifocal (involving multiple sites within the gland) and bilateral in up to 20-80% of cases, which often influences the decision for total thyroidectomy. * **Option D (Distant metastasis):** Although rare compared to lymphatic spread, distant metastasis can occur, most commonly involving the **lungs** (often presenting as a miliary pattern) and occasionally the bones. **NEET-PG High-Yield Pearls:** * **Most common** thyroid cancer overall and most common after radiation exposure. * **Microscopic Hallmarks:** Psammoma bodies (calcified laminations), Orphan Annie eye nuclei (clear nuclei), and nuclear grooves. * **Prognosis:** Generally excellent; the **AMES** (Age, Metastasis, Extent, Size) and **MACIS** scores are used for staging. * **BRAF Mutation:** The most common genetic mutation associated with PTC.

Question 72: A patient with long-standing multinodular goitre develops hoarseness of voice, and the swelling undergoes a sudden increase in size. What is the likely diagnosis?

A. Follicular carcinoma (Correct Answer)
B. Papillary carcinoma
C. Medullary carcinoma
D. Anaplastic carcinoma

Explanation: ### Explanation The clinical presentation of a **sudden increase in size** of a long-standing multinodular goitre (MNG) associated with **hoarseness of voice** (suggestive of recurrent laryngeal nerve palsy) is a classic indicator of malignant transformation. **Why Follicular Carcinoma is the correct answer:** Follicular carcinoma (FC) typically arises in patients with a pre-existing long-standing goitre, especially in iodine-deficient areas. While it usually spreads hematogenously, a sudden rapid growth in a chronic MNG is a hallmark of FC. The hoarseness indicates local invasion into the recurrent laryngeal nerve, a sign of advanced disease or aggressive transformation. **Analysis of Incorrect Options:** * **Papillary Carcinoma:** This is the most common thyroid malignancy. It usually presents as a slow-growing, painless "cold" nodule and often spreads via lymphatics. It is less commonly associated with a sudden transformation of a long-standing MNG compared to FC. * **Medullary Carcinoma:** This arises from parafollicular C-cells. It is often associated with MEN 2 syndromes and presents with elevated calcitonin levels. It does not typically arise from a pre-existing MNG. * **Anaplastic Carcinoma:** While this presents with extremely rapid growth and pressure symptoms (dyspnea, dysphagia, hoarseness), it usually occurs in much older patients (6th–7th decade) and the growth is "explosive" (weeks) rather than just "sudden." While a possible differential, in the context of standard NEET-PG patterns, a sudden change in a chronic MNG is the classic description for Follicular Carcinoma. **High-Yield Clinical Pearls for NEET-PG:** * **Follicular Carcinoma:** Hematogenous spread is common (bones, lungs). Diagnosis **cannot** be made by FNAC; it requires histopathology to demonstrate capsular or vascular invasion. * **Orphan Annie Eye nuclei:** Pathognomonic for Papillary Carcinoma. * **Psammoma bodies:** Seen in Papillary thyroid cancer. * **Amyloid stroma:** Characteristic of Medullary thyroid cancer.

Question 73: In which type of thyroid carcinoma is treatment with radioactive iodine (1-131) most beneficial?

A. Papillary carcinoma
B. Follicular carcinoma (Correct Answer)
C. Anaplastic carcinoma
D. Medullary carcinoma

Explanation: **Explanation:** The efficacy of **Radioactive Iodine (I-131) therapy** depends on the expression of the **Sodium-Iodide Symporter (NIS)**, which allows thyroid cells to trap iodine. **Why Follicular Carcinoma is the correct answer:** While both Papillary and Follicular carcinomas are "Differentiated Thyroid Cancers" (DTC) and can take up iodine, **Follicular Thyroid Carcinoma (FTC)** typically shows a higher and more uniform affinity for I-131. FTC has a greater propensity for **hematogenous spread** (e.g., to bone and lungs). Radioactive iodine is the mainstay for treating these distant metastases, as the well-differentiated follicular cells avidly take up the isotope, leading to targeted destruction of micrometastases. **Analysis of Incorrect Options:** * **A. Papillary Carcinoma:** Although it is the most common DTC and often treated with I-131 post-thyroidectomy, it primarily spreads via lymphatics. Some variants (like the tall cell variant) may have lower iodine uptake compared to classic FTC. * **C. Anaplastic Carcinoma:** This is an undifferentiated tumor. The cells lose all functional characteristics of thyroid tissue, including the NIS protein, making them completely **radio-resistant** to I-131. * **D. Medullary Carcinoma:** This tumor arises from **Parafollicular C-cells**, which do not trap iodine. Therefore, I-131 has no role in its management. **High-Yield Clinical Pearls for NEET-PG:** * **Pre-requisite for I-131:** High TSH levels (>30 mIU/L) are required to stimulate NIS expression before therapy (achieved by thyroxine withdrawal or recombinant human TSH). * **Monitoring:** **Serum Thyroglobulin** is the tumor marker used to monitor recurrence in DTC after total thyroidectomy and ablation. * **Medullary Carcinoma Marker:** Calcitonin and CEA. * **Diagnosis:** FTC cannot be diagnosed by FNAC (requires histological proof of capsular or vascular invasion); Papillary carcinoma is easily diagnosed by FNAC (Orphan Annie eye nuclei).

Question 74: Compared to follicular carcinoma, papillary carcinoma of the thyroid is associated with which of the following?

A. More male preponderance
B. Radiation exposure (Correct Answer)
C. Iodine deficiency
D. Increased mortality

Explanation: **Explanation:** The correct answer is **Radiation exposure**. Papillary Thyroid Carcinoma (PTC) is the most common thyroid malignancy and has a strong, well-documented association with prior exposure to ionizing radiation (e.g., childhood neck irradiation or nuclear accidents). In contrast, Follicular Thyroid Carcinoma (FTC) is more closely linked to dietary factors. **Analysis of Options:** * **Radiation Exposure (Correct):** Ionizing radiation is a major risk factor for PTC, often involving mutations in the *RET/PTC* rearrangement or *BRAF* gene. * **More Male Preponderance (Incorrect):** Both PTC and FTC are significantly more common in females (approx. 3:1 ratio). There is no male preponderance for PTC. * **Iodine Deficiency (Incorrect):** This is a classic risk factor for **Follicular Carcinoma** and Anaplastic Carcinoma. In contrast, iodine-rich areas often see a higher relative incidence of Papillary Carcinoma. * **Increased Mortality (Incorrect):** PTC has an excellent prognosis with a 10-year survival rate exceeding 90-95%. FTC is generally more aggressive than PTC due to its tendency for early hematogenous spread (to bone and lungs), whereas PTC primarily spreads via lymphatics. **High-Yield Clinical Pearls for NEET-PG:** * **Psammoma Bodies:** Laminated calcifications pathognomonic for PTC (found in 50% of cases). * **Orphan Annie Eye Nuclei:** Characteristic clear/ground-glass nuclei seen in PTC. * **Spread:** PTC spreads **Lymphatically** (most common site: Level VI nodes); FTC spreads **Hematogenously**. * **Diagnosis:** PTC can be diagnosed via FNAC (nuclear features); FTC **cannot** be diagnosed by FNAC (requires histological proof of capsular or vascular invasion).

Question 75: What is true regarding incidental adrenal masses?

A. May be seen in as many as 10% of abdominal CT studies.
B. Most commonly represent pheochromocytoma; adrenocortical adenoma, adrenocortical carcinoma, and metastases from other primary cancers occur less frequently.
C. May represent adrenocortical carcinoma if greater than 6 cm in diameter. (Correct Answer)
D. Should be routinely evaluated by measurement of 24-hour urine levels of catecholamines and their metabolites, cortisol, and aldosterone plus fine-needle aspiration.

Explanation: ### Explanation **1. Why Option C is Correct:** The size of an adrenal incidentaloma is a critical predictor of malignancy. While most incidentalomas are benign, the risk of **Adrenocortical Carcinoma (ACC)** increases significantly with size. Lesions **>6 cm** have a 25% risk of being malignant, making surgical resection (adrenalectomy) mandatory. Conversely, lesions <4 cm are usually benign, and those between 4–6 cm fall into a "grey zone" requiring close monitoring or surgery based on imaging characteristics. **2. Why Other Options are Incorrect:** * **Option A:** Adrenal incidentalomas are found in approximately **4–5%** of abdominal CT scans, not 10%. The prevalence increases with age (up to 7–10% in the elderly). * **Option B:** The most common cause of an adrenal incidentaloma is a **non-functioning adrenocortical adenoma** (approx. 70–80%). Pheochromocytomas and metastases are much less common. * **Option D:** While biochemical screening for catecholamines, cortisol (Dexamethasone Suppression Test), and aldosterone (if hypertensive) is mandatory, **Fine-Needle Aspiration (FNA) is NOT routine.** FNA cannot distinguish between benign adenoma and ACC; its only role is to confirm metastatic disease in a patient with a known primary extra-adrenal cancer, and only *after* ruling out pheochromocytoma to avoid a hypertensive crisis. ### NEET-PG High-Yield Pearls: * **Definition:** An adrenal mass ≥1 cm found incidentally on imaging performed for reasons other than suspected adrenal disease. * **Initial Workup:** Every patient needs a biochemical workup to rule out hyperfunction (Pheochromocytoma, Cushing’s, and Conn’s syndrome). * **Imaging Phenotype:** Benign adenomas typically have **low Hounsfield Units (HU <10)** on non-contrast CT due to high lipid content and rapid contrast washout (>60% at 10–15 mins). * **Surgical Threshold:** Adrenalectomy is indicated for all functional tumors or non-functional tumors >4–6 cm.

Question 76: Which of the following is FALSE regarding medullary carcinoma of the thyroid?

A. The tumor marker is calcitonin.
B. It arises from parafollicular cells.
C. It is associated with RET mutations.
D. It is familial in 90% of cases. (Correct Answer)

Explanation: **Explanation:** Medullary Thyroid Carcinoma (MTC) is a unique neuroendocrine tumor. The correct answer is **D** because the statement is factually reversed: **75–80% of MTC cases are sporadic**, while only **20–25% are familial** (associated with MEN 2A, MEN 2B, or Familial MTC). * **Option A (Incorrect):** Calcitonin is the primary tumor marker for MTC. It is used for diagnosis, screening of family members, and monitoring recurrence. Carcinoembryonic antigen (CEA) is also used as a secondary marker. * **Option B (Incorrect):** MTC arises from the **Parafollicular C-cells**, which are derived from the **ultimobranchial body** (neural crest origin). Unlike papillary or follicular cancers, MTC does not arise from follicular cells and thus does not concentrate iodine. * **Option C (Incorrect):** The **RET proto-oncogene** mutation is the hallmark of MTC. It is present in nearly 100% of familial cases (germline mutation) and approximately 50% of sporadic cases (somatic mutation). **High-Yield Clinical Pearls for NEET-PG:** * **Amyloid Stroma:** Histology typically shows nests of cells with "apple-green birefringence" on Congo Red staining due to procalcitonin deposition. * **Management:** The treatment of choice is **Total Thyroidectomy with Central Compartment Neck Dissection**. * **Screening:** In patients with known RET mutations, prophylactic thyroidectomy is recommended (at age 5 for MEN 2A and infancy for MEN 2B). * **Rule out Pheochromocytoma:** Always screen for pheochromocytoma before surgery in familial cases to prevent a hypertensive crisis during anesthesia.

Question 77: Which type of carcinoma most commonly arises in a thyroglossal cyst?

A. Follicular
B. Medullary
C. Papillary (Correct Answer)
D. Anaplastic

Explanation: **Explanation:** A thyroglossal duct cyst (TGDC) is the most common congenital neck swelling, resulting from a failure of the thyroglossal duct to obliterate. While malignancy is rare (occurring in <1% of cases), when it does occur, it is almost always of thyroid follicular cell origin. **1. Why Papillary Carcinoma is Correct:** **Papillary Thyroid Carcinoma (PTC)** accounts for approximately **85–90%** of all malignancies arising in a thyroglossal cyst. The reason is attributed to the presence of ectopic thyroid tissue within the cyst wall. Since PTC is the most common type of thyroid cancer in the general population, it is also the most frequent histological subtype found in these remnants. **2. Why Other Options are Incorrect:** * **Follicular Carcinoma:** While it arises from follicular cells, it is significantly less common than PTC in this location (approx. 5–7%). * **Medullary Carcinoma:** This arises from **Parafollicular C-cells**, which are derived from the **ultimobranchial body** (4th branchial pouch), not the thyroglossal duct. Therefore, Medullary carcinoma is virtually never found in a TGDC. * **Anaplastic Carcinoma:** This is an extremely rare, undifferentiated tumor. While theoretically possible, it is not the "most common." **3. NEET-PG High-Yield Pearls:** * **Sistrunk Operation:** The definitive surgical treatment for TGDC, involving excision of the cyst, the entire duct, and the **central portion of the hyoid bone** to prevent recurrence. * **Diagnosis:** Often an incidental finding on histopathology after a Sistrunk procedure. * **Management of Malignancy:** If a TGDC contains PTC, a Sistrunk procedure is often sufficient if the thyroid gland itself is normal on ultrasound. Total thyroidectomy is considered if there are suspicious nodules in the main thyroid gland or cervical lymphadenopathy.

Question 78: A male patient in a euthyroid state presents with which of the following conditions?

A. Thyroglossal cyst
B. Multiple nodular goiter (Correct Answer)
C. Solitary thyroid nodule
D. Toxic nodular goiter

Explanation: ### Explanation **1. Why Multiple Nodular Goiter (MNG) is the Correct Answer:** In the context of standard surgical presentations, **Multinodular Goiter (MNG)** is the classic example of a thyroid swelling where the patient typically remains in a **euthyroid state**. The pathophysiology involves cycles of hyperplasia and involution due to fluctuating TSH levels or iodine deficiency, leading to thyroid enlargement without necessarily causing functional overactivity. While some MNGs can become toxic (Plummer’s disease), the vast majority encountered in clinical practice and exams are "non-toxic" or euthyroid. **2. Analysis of Incorrect Options:** * **Thyroglossal Cyst (Option A):** While patients are usually euthyroid, this is a **developmental anomaly** (persistent thyroglossal duct) rather than a primary thyroid gland pathology. It is often midline and moves with protrusion of the tongue. * **Solitary Thyroid Nodule (Option C):** A solitary nodule can be euthyroid, but it carries a higher risk of **malignancy** (approx. 5-15%) or may be a "hot" toxic nodule. MNG is a more definitive clinical representation of a benign euthyroid enlargement. * **Toxic Nodular Goiter (Option D):** By definition, "toxic" implies **hyperthyroidism**. These patients present with suppressed TSH and elevated T3/T4 levels, manifesting clinical symptoms like tachycardia and tremors. **3. Clinical Pearls for NEET-PG:** * **Most common cause of goiter worldwide:** Iodine deficiency. * **Pemberton’s Sign:** Used to detect retrosternal extension in MNG; look for facial flushing and inspiratory stridor upon raising both arms. * **Investigation of Choice:** FNAC is the gold standard for evaluating nodules within an MNG to rule out malignancy (Dominant nodule). * **Treatment:** For euthyroid MNG, surgery (Total Thyroidectomy) is indicated only if there are pressure symptoms, retrosternal extension, or cosmetic concerns.

Question 79: A 30-year-old pregnant woman presents with a history of thyroid swelling. FNAC report shows papillary carcinoma of the thyroid, and the nodule was cold on radioiodine uptake scan. Which of the following is NOT a treatment option?

A. Thyroidectomy (Correct Answer)
B. Right-sided hemithyroidectomy
C. Lobectomy
D. Radioiodine ablation of the thyroid

Explanation: **Explanation:** The core concept in this question is the **contraindication of radioactive substances during pregnancy**. **Why Option D (Radioiodine ablation) is the correct answer (NOT an option):** Radioactive Iodine (I-131) is strictly contraindicated during pregnancy. It crosses the placenta and can be concentrated by the fetal thyroid gland (which begins functioning at 10–12 weeks of gestation), leading to **fetal hypothyroidism**, thyroid destruction, and potential teratogenic effects. Additionally, the radioiodine uptake scan mentioned in the stem is typically avoided in pregnancy; diagnosis is usually made via ultrasound and FNAC. **Why the other options are incorrect (They ARE treatment options):** * **A, B, and C (Surgical options):** Surgery is the mainstay of treatment for Papillary Thyroid Carcinoma (PTC) during pregnancy. If diagnosed in the 1st or 2nd trimester, surgery is ideally performed during the **2nd trimester** (when organogenesis is complete and the risk of preterm labor is lowest). If diagnosed in the 3rd trimester, surgery can often be deferred until the postpartum period unless the disease is rapidly progressive. Depending on the size and extent of the tumor, a Lobectomy, Hemithyroidectomy, or Total Thyroidectomy can be safely performed. **High-Yield Clinical Pearls for NEET-PG:** * **Most common thyroid cancer in pregnancy:** Papillary Carcinoma. * **Safe window for surgery:** 2nd Trimester (specifically before 24 weeks). * **I-131 and Breastfeeding:** Also contraindicated; it is secreted in breast milk. * **Suppressive Therapy:** If surgery is deferred until postpartum, the patient is started on **L-Thyroxine** to keep TSH levels low (0.1–0.5 mU/L) to prevent tumor growth.

Question 80: What serum marker is used after surgery for differentiated thyroid cancer?

A. T4
B. Thyroglobulin (Correct Answer)
C. Calcitonin
D. PTH

Explanation: **Explanation:** **Thyroglobulin (Tg)** is the correct answer because it serves as a highly specific tumor marker for **Differentiated Thyroid Cancer (DTC)**, which includes Papillary and Follicular carcinomas. 1. **Why Thyroglobulin?** Tg is a glycoprotein produced exclusively by follicular cells of the thyroid. After a total thyroidectomy and radioactive iodine (RAI) ablation, there should be no remaining thyroid tissue. Therefore, any detectable serum Tg during follow-up indicates persistent or recurrent disease. It is often measured alongside **Anti-thyroglobulin antibodies (anti-TgAb)**, as their presence can falsely lower Tg readings. 2. **Why the others are incorrect:** * **T4 (Thyroxine):** This is a hormone used for replacement therapy post-surgery, not a marker for recurrence. * **Calcitonin:** This is the specific tumor marker for **Medullary Thyroid Cancer (MTC)**, which arises from parafollicular C-cells, not DTC. * **PTH (Parathyroid Hormone):** This is monitored post-thyroidectomy to check for accidental damage or removal of the parathyroid glands (hypoparathyroidism), but it is not a cancer marker. **High-Yield Clinical Pearls for NEET-PG:** * **Stimulated Tg:** Tg levels are most sensitive when TSH is high (either by stopping T4 or giving recombinant TSH). * **Mnemonic:** **M**edullary = **M**arker is Calcitonin; **D**ifferentiated = **D**etected by Thyroglobulin. * **Hurthle Cell Carcinoma:** Also uses Thyroglobulin as a marker. * **Anaplastic Carcinoma:** Does not have a reliable serum marker as the cells are too undifferentiated to produce Tg.

Practice by Chapter

Thyroid Nodules

Practice Questions

Thyroid Cancer

Practice Questions

Graves' Disease

Practice Questions

Thyroiditis

Practice Questions

Primary Hyperparathyroidism

Practice Questions

Secondary and Tertiary Hyperparathyroidism

Practice Questions

Adrenal Cortical Tumors

Practice Questions

Pheochromocytoma

Practice Questions

Adrenal Incidentalomas

Practice Questions

Multiple Endocrine Neoplasia

Practice Questions

Neuroendocrine Tumors

Practice Questions

Intraoperative Monitoring in Endocrine Surgery

Practice Questions

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