Endocrine Surgery — MCQs

Endocrine Surgery Indian Medical PG Practice Questions and MCQs

Question 241: What is the most common histological type of thyroid carcinoma?

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

Explanation: **Explanation:** Thyroid carcinomas are classified based on their histological origin. **Papillary Thyroid Carcinoma (PTC)** is the most common histological type, accounting for approximately **80–85%** of all thyroid malignancies. It typically presents as a slow-growing, painless thyroid nodule and has an excellent prognosis. **Why the other options are incorrect:** * **Follicular Carcinoma (Option A):** This is the second most common type (approx. 10–15%). Unlike PTC, it tends to spread hematogenously (to bone and lungs) rather than via lymphatics. * **Anaplastic Carcinoma (Option C):** This is the rarest (<2%) but most aggressive form. it typically occurs in elderly patients and has a very poor prognosis. * **Medullary Carcinoma (Option D):** This arises from the parafollicular C-cells (secreting calcitonin) and accounts for about 5% of cases. It can be sporadic or associated with MEN 2A/2B syndromes. **High-Yield Clinical Pearls for NEET-PG:** 1. **Risk Factor:** The most significant risk factor for Papillary Carcinoma is prior exposure to **ionizing radiation**. 2. **Histological Hallmarks:** Look for **Psammoma bodies** (laminated calcifications) and characteristic nuclear features: **Orphan Annie eye nuclei** (clear/ground-glass appearance) and **nuclear grooves/pseudoinclusions**. 3. **Spread:** PTC primarily spreads via the **lymphatics** to cervical lymph nodes. 4. **Investigation of Choice:** **FNAC** is the gold standard for diagnosis (except for Follicular carcinoma, which requires histopathology to see capsular/vascular invasion).

Question 242: What is the most common nerve injury associated with thyroid surgery?

A. Right recurrent laryngeal nerve
B. Left recurrent laryngeal nerve
C. Right internal laryngeal nerve
D. External branch of superior laryngeal nerve (Correct Answer)

Explanation: The correct answer is **D. External branch of superior laryngeal nerve (EBSLN)**. ### **Explanation** The **External branch of the Superior Laryngeal Nerve (EBSLN)** is the most commonly injured nerve in thyroid surgery. This is because of its close anatomical proximity to the **superior thyroid artery**. It often runs just deep to or within the fascia of the inferior constrictor muscle before supplying the **cricothyroid muscle**. During the ligation of the superior vascular pedicle, if the vessels are not divided close to the thyroid gland, the EBSLN is easily clamped or transected. ### **Analysis of Incorrect Options** * **A & B (Recurrent Laryngeal Nerve - RLN):** While RLN injury is the most *feared* complication due to its dramatic presentation (hoarseness or airway obstruction), it is statistically less common than EBSLN injury. The **Right RLN** is slightly more prone to injury than the left because it follows a more oblique course and is not protected in the tracheoesophageal groove as consistently as the left. * **C (Internal Laryngeal Nerve):** This is a branch of the Superior Laryngeal Nerve that provides sensory innervation to the supraglottic larynx. It is rarely injured during routine thyroidectomy as it enters the thyrohyoid membrane well above the surgical field. ### **Clinical Pearls for NEET-PG** * **EBSLN Injury:** Results in the inability to tense the vocal cords. Clinically, the patient loses the ability to produce **high-pitched sounds** (the "singer’s nerve"). It presents as vocal fatigue or a "weak" voice. * **Unilateral RLN Injury:** Most common symptom is **hoarseness** of voice. The vocal cord assumes a **paramedian position**. * **Bilateral RLN Injury:** This is a surgical emergency. It leads to **stridor** and respiratory distress, often requiring an emergency tracheostomy. * **Prevention:** To avoid EBSLN injury, ligate the superior thyroid artery **individually and as close to the gland** as possible. To avoid RLN injury, ligate the inferior thyroid artery **away from the gland** (trunk ligation).

Question 243: Fine-needle aspiration cytology (FNAC) is the investigation of choice in which of the following thyroid conditions?

A. Papillary carcinoma
B. Medullary carcinoma
C. Anaplastic carcinoma (Correct Answer)
D. None of the above

Explanation: **Explanation:** Fine-needle aspiration cytology (FNAC) is the gold standard and initial investigation of choice for evaluating thyroid nodules. However, its diagnostic utility varies across different histological types. **Why Anaplastic Carcinoma is the correct answer:** In **Anaplastic Carcinoma**, FNAC is highly diagnostic because the cells are markedly pleomorphic, giant, or spindle-shaped, showing clear features of high-grade malignancy. Since the diagnosis is based on cellular morphology rather than tissue architecture, FNAC is the investigation of choice to confirm this rapidly growing, aggressive tumor. **Analysis of Incorrect Options:** * **Papillary Carcinoma (A):** While FNAC is excellent for Papillary Carcinoma (identifying Orphan Annie eye nuclei, Psammoma bodies, and nuclear grooves), it is often considered the "investigation of choice" for *screening* all thyroid nodules. However, in the context of this specific question format, Anaplastic is often highlighted because it provides a definitive diagnosis of malignancy without the ambiguity sometimes found in other types. * **Medullary Carcinoma (B):** FNAC can suggest Medullary Carcinoma (showing amyloid stroma or spindle cells), but the definitive diagnosis often requires calcitonin levels or immunohistochemistry (IHC) for confirmation. * **Follicular Carcinoma (Not listed but crucial):** FNAC **cannot** distinguish between Follicular Adenoma and Follicular Carcinoma because the diagnosis of carcinoma requires evidence of **capsular or vascular invasion**, which can only be seen on histopathology (biopsy), not cytology. **NEET-PG High-Yield Pearls:** * **FNAC Limitation:** The most significant limitation of thyroid FNAC is its inability to diagnose **Follicular Carcinoma**. * **Bethesda System:** Thyroid FNAC results are reported using the Bethesda System (I-VI). * **Best Initial Test:** For a thyroid nodule, the first step is TSH levels; if TSH is normal, the next step is Ultrasound-guided FNAC. * **Anaplastic Carcinoma:** Usually presents in elderly patients as a rapidly enlarging neck mass with pressure symptoms (dyspnea/dysphagia).

Question 244: Occult thyroid malignancy with nodal metastasis is seen in which type?

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

Explanation: **Explanation:** The correct answer is **Papillary Thyroid Carcinoma (PTC)**. **Why Papillary Carcinoma is correct:** Papillary carcinoma is the most common type of thyroid malignancy and is characterized by its **lymphatic spread**. The term "Occult Papillary Carcinoma" (also known as a microcarcinoma) refers to a tumor less than 1 cm in diameter that is often clinically silent. Frequently, the first clinical presentation of an occult PTC is a **palpable cervical lymph node** (lateral aberrant thyroid), while the primary tumor remains non-palpable within the thyroid gland. **Why the other options are incorrect:** * **Follicular Carcinoma:** This type primarily spreads via the **hematogenous route** (bloodstream) to bones and lungs. Nodal involvement is rare (less than 10%), making it an unlikely candidate for occult presentation via nodal metastasis. * **Medullary Carcinoma:** While it does spread to lymph nodes, it arises from parafollicular C-cells and is usually associated with elevated Calcitonin levels. It is less likely than PTC to present as an isolated occult nodal mass. * **Anaplastic Carcinoma:** This is a highly aggressive, rapidly growing tumor. It presents as a massive, fixed neck swelling with compressive symptoms; it is never "occult" by the time it metastasizes. **High-Yield Clinical Pearls for NEET-PG:** * **Psammoma bodies:** Characteristic laminated calcifications seen in PTC. * **Orphan Annie Eye nuclei:** Pathognomonic nuclear clearing seen in PTC. * **Lateral Aberrant Thyroid:** A historical term for a cervical lymph node containing metastatic papillary thyroid tissue. * **Prognosis:** PTC has an excellent prognosis despite nodal metastasis, which (unlike in other cancers) does not significantly worsen the survival rate in younger patients.

Question 245: What is the primary cause of thyroid storm post-total thyroidectomy?

A. Excessive manipulation of the thyroid gland during surgery.
B. Insufficient preoperative preparation of the patient. (Correct Answer)
C. Injury to the recurrent laryngeal nerve.
D. Damage to the parathyroid glands.

Explanation: **Explanation:** Thyroid storm is a life-threatening exacerbation of hyperthyroidism characterized by a hypermetabolic state. In the context of surgery, the **primary cause** is **insufficient preoperative preparation (Option B)**. Patients with Graves' disease or toxic multinodular goiter must be rendered **euthyroid** before surgery using antithyroid drugs (Methimazole/PTU) and Beta-blockers. If a patient undergoes surgery while still thyrotoxic, the physiological stress of anesthesia and surgery triggers a massive release of thyroid hormones ($T_3$ and $T_4$) into the circulation, leading to a storm. **Analysis of Incorrect Options:** * **Option A:** While excessive manipulation was historically blamed, modern evidence shows that surgical trauma alone rarely triggers a storm if the patient is biochemically euthyroid. * **Option C:** Injury to the recurrent laryngeal nerve causes vocal cord palsy (hoarseness or airway obstruction) but has no effect on thyroid hormone levels. * **Option D:** Damage to the parathyroid glands leads to hypocalcemia (tetany), which is a common post-thyroidectomy complication but unrelated to thyroid storm. **High-Yield Clinical Pearls for NEET-PG:** * **Pre-op Preparation:** Lugol’s iodine or Potassium Iodide (SSKI) is often given 10 days pre-operatively to decrease the vascularity and friability of the gland. * **Clinical Features:** Hyperpyrexia (>104°F), tachycardia, arrhythmias (Atrial Fibrillation), and CNS agitation. * **Management (The "P"s):** **P**ropylthiouracil (blocks synthesis and peripheral $T_4 \to T_3$ conversion), **P**ropranolol (symptom control), **P**rednisolone (steroids), and **P**otassium Iodide (after antithyroid drugs).

Question 246: Localization in insulinoma is best with which imaging modality?

A. Contrast computerized tomography
B. Magnetic resonance imaging
C. Somatostatin receptor scintigraphy
D. Selective angiography (Correct Answer)

Explanation: **Explanation:** Insulinomas are the most common functional neuroendocrine tumors (NETs) of the pancreas. They are typically small (<2 cm), solitary, and benign. The primary challenge in management is localization. **Why Selective Angiography is the Correct Answer:** While non-invasive imaging is performed first, **Selective Angiography** (specifically when combined with calcium stimulation) is historically and classically considered the most sensitive modality for localization. In the **Calcium Stimulation Venous Sampling (ASVS) test**, calcium gluconate is injected into the gastroduodenal, superior mesenteric, and splenic arteries. A rise in insulin levels in the hepatic vein identifies the specific anatomical region (head, body, or tail) of the tumor. It has a sensitivity of >90%, surpassing standard CT/MRI for small lesions. **Why Other Options are Incorrect:** * **A & B (CT/MRI):** These are the initial screening tests. However, because insulinomas are often very small and isodense with the pancreas, CT and MRI have lower sensitivity (approx. 40–70%). * **C (Somatostatin Receptor Scintigraphy/Octreoscan):** Unlike other NETs (like gastrinomas), only about 50% of insulinomas express somatostatin receptors (SSTR2). Therefore, Octreoscan is unreliable for insulinoma localization. **Clinical Pearls for NEET-PG:** * **Whipple’s Triad:** Symptoms of hypoglycemia, low plasma glucose (<50 mg/dL), and relief of symptoms after glucose administration. * **Gold Standard for Localization:** **Endoscopic Ultrasound (EUS)** is now the preferred *pre-operative* investigation (sensitivity 80–90%). * **Most Sensitive Overall:** **Intra-operative Ultrasound (IOUS)** combined with surgical palpation is the most accurate method (95–100% sensitivity) to locate the tumor during surgery. * **Medical Management:** Diazoxide is used to inhibit insulin release in unresectable cases.

Question 247: A 32-year-old male presents with a painless cervical lymph node. Lymph node biopsy reveals normal thyroid gland features, and the thyroid is clinically normal on palpation. What is the most likely diagnosis?

A. Lateral aberrant thyroid
B. Follicular carcinoma thyroid with metastatic lymph nodes
C. Papillary carcinoma thyroid (Correct Answer)
D. Anaplastic carcinoma

Explanation: **Explanation:** The clinical presentation of "normal thyroid tissue" within a cervical lymph node is a classic description of **metastatic Papillary Carcinoma of the Thyroid (PTC)**. **1. Why Papillary Carcinoma is correct:** In the past, this presentation was mistakenly called "Lateral Aberrant Thyroid." However, it is now a fundamental surgical principle that **there is no such thing as a lateral aberrant thyroid.** Any thyroid tissue found in a cervical lymph node is considered a metastasis from a primary thyroid malignancy until proven otherwise. PTC is the most common thyroid cancer and is highly lymphophilic. It often presents as a "node-first" disease where the primary tumor in the thyroid gland is occult (too small to be felt on palpation), but the lymph node contains well-differentiated thyroid follicles that look "normal" under light microscopy. **2. Why other options are incorrect:** * **Lateral Aberrant Thyroid:** This is an obsolete term. Embryologically, the thyroid descends midline; lateral thyroid tissue is almost always metastatic PTC. * **Follicular Carcinoma:** This subtype typically spreads via the **hematogenous route** (blood) to bones and lungs, rather than the lymphatic route. * **Anaplastic Carcinoma:** This is a highly aggressive, undifferentiated tumor seen in elderly patients. It would show high-grade pleomorphism on biopsy, not "normal thyroid features," and usually presents as a rapidly growing, painful mass. **Clinical Pearls for NEET-PG:** * **Occult Primary:** PTC is the most common cause of an occult primary presenting as a cervical neck mass. * **Psammoma Bodies:** Look for these laminated calcifications in the pathology description of PTC. * **Orphan Annie Eye Nuclei:** The pathognomonic nuclear feature of PTC. * **Investigation of Choice:** Ultrasound-guided FNAC of the node and the thyroid gland.

Question 248: What percentage of cold nodules on thyroid scans are malignant?

A. 5%
B. 15%
C. 20% (Correct Answer)
D. 40%

Explanation: ### Explanation **Concept Overview:** Thyroid nodules are evaluated functionally using radionuclide scanning (Technetium-99m or Iodine-123). Nodules are classified based on their uptake of the isotope compared to the surrounding thyroid parenchyma: * **Hot (Hyperfunctioning):** Increased uptake; almost never malignant (<1%). * **Warm (Isfunctioning):** Normal uptake; low risk of malignancy. * **Cold (Hypofunctioning):** Decreased or absent uptake; these carry the highest risk of malignancy. **Why 20% is Correct:** Statistically, approximately **15% to 20%** of cold nodules are found to be malignant upon further investigation (FNAC/Histopathology). While most cold nodules (80-85%) are benign (e.g., colloid cysts, adenomas, or thyroiditis), the 20% malignancy rate is the standard high-yield figure used in surgical textbooks (like Bailey & Love and Sabiston) and medical examinations. **Analysis of Incorrect Options:** * **A (5%):** This represents the overall prevalence of malignancy in *all* thyroid nodules (including hot and warm), not specifically cold nodules. * **B (15%):** While some studies cite 15%, 20% is the more commonly tested upper limit for the risk associated with a solitary cold nodule. * **D (40%):** This significantly overestimates the risk. Even a cold nodule is more likely to be benign than malignant. **High-Yield Clinical Pearls for NEET-PG:** * **Investigation of Choice:** FNAC is the gold standard for evaluating a thyroid nodule. Radionuclide scans are now secondary to Ultrasound and FNAC. * **Hot Nodule Rule:** A "hot" nodule is reassuring as it indicates a functioning adenoma (e.g., Toxic Adenoma/Plummer’s Disease) and rarely requires biopsy. * **Risk Factors:** The risk of malignancy in a cold nodule increases if the patient is male, very young (<20 years), or very old (>70 years), or has a history of neck irradiation.

Question 249: Which of the following is NOT a common complication of hemithyroidectomy?

A. Hypoparathyroidism (Correct Answer)
B. Reactionary hemorrhage
C. Recurrent laryngeal nerve palsy
D. External laryngeal nerve palsy

Explanation: **Explanation:** The correct answer is **A. Hypoparathyroidism**. In a **hemithyroidectomy** (lobectomy), only one side of the thyroid gland is removed. Humans typically possess four parathyroid glands (two on each side). Even if the two parathyroid glands on the operated side are inadvertently removed or their blood supply is compromised, the two contralateral parathyroid glands remain intact and are sufficient to maintain normal calcium homeostasis. Therefore, permanent or even transient symptomatic hypocalcemia/hypoparathyroidism is virtually non-existent in unilateral surgery. This complication is typically associated with **total or completion thyroidectomy**. **Analysis of Incorrect Options:** * **B. Reactionary hemorrhage:** This is a potential complication of any thyroid surgery, usually occurring within the first 24 hours due to a slipped ligature or "bucking" during extubation. It can lead to life-threatening airway obstruction. * **C. Recurrent laryngeal nerve (RLN) palsy:** The RLN lies in the tracheoesophageal groove and is at risk during any dissection near the inferior thyroid artery or the ligament of Berry, even in unilateral procedures. * **D. External laryngeal nerve (ELN) palsy:** The ELN (branch of the Superior Laryngeal Nerve) is at risk during the ligation of the superior thyroid vessels. Damage results in the inability to create high-pitched sounds due to cricothyroid muscle paralysis. **NEET-PG High-Yield Pearls:** * **Most common cause of hypoparathyroidism:** Post-surgical (following total thyroidectomy). * **Most common nerve injured in thyroidectomy:** External Laryngeal Nerve (presents as voice fatigue). * **Most serious immediate complication:** Reactionary hemorrhage causing tension hematoma. * **Chvostek’s and Trousseau’s signs:** Clinical indicators of latent tetany due to hypocalcemia.

Question 250: What is the initial preferred investigation for a thyroid nodule?

A. Fine Needle Aspiration Cytology (FNAC)
B. Radionuclide scan
C. Thyroid function test (Correct Answer)
D. Ultrasound (USG)

Explanation: The evaluation of a thyroid nodule follows a systematic diagnostic algorithm. The **initial preferred investigation** is a **Thyroid Function Test (TFT)**, specifically measuring Serum TSH levels. ### Why Thyroid Function Test (TFT) is the correct answer: The primary goal of the initial step is to determine the functional status of the nodule. * If **TSH is suppressed (low)**, it suggests a hyperfunctioning ("hot") nodule, which is rarely malignant. This directs the clinician toward a radionuclide scan. * If **TSH is normal or elevated**, the risk of malignancy is higher, and the next step is typically an Ultrasound followed by FNAC if indicated. Starting with TSH ensures that patients with functional nodules do not undergo unnecessary invasive procedures like FNAC. ### Why other options are incorrect: * **Ultrasound (USG):** While USG is the most sensitive tool for characterizing the anatomy and suspicious features (e.g., microcalcifications, irregular margins), it is usually performed concurrently with or immediately after the TSH result is known. * **Fine Needle Aspiration Cytology (FNAC):** This is the **gold standard** for diagnosing malignancy, but it is not the *initial* step. It is performed only after confirming the nodule is non-functional. * **Radionuclide Scan:** This is indicated only if the TSH is low. It is no longer a routine first-line test for all nodules. ### High-Yield Clinical Pearls for NEET-PG: * **Best Initial Test:** Serum TSH (TFT). * **Most Accurate/Gold Standard:** FNAC. * **First Imaging Modality:** Ultrasound. * **FNAC Contraindication:** FNAC should not be performed in a "Hot Nodule" (risk of bleeding and low diagnostic yield as hot nodules are almost always benign). * **Follicular Carcinoma:** FNAC cannot distinguish between follicular adenoma and carcinoma; histopathology (showing capsular or vascular invasion) is required.

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

Want unlimited practice?

Get full access to all questions, explanations, and performance tracking.

Start For Free