Endocrine Surgery Practice Questions

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

Papillary type. **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).

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

Papillary carcinoma. **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.

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

Insufficient preoperative preparation of the patient.. **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).

Q: Localization in insulinoma is best with which imaging modality?

Selective angiography. **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.

Q: 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?

Papillary carcinoma thyroid. **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.

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

20%. ### 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 ( 70 years), or has a history of neck irradiation.

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

Hypoparathyroidism. **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.

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

Thyroid function test. 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.

Question 1

What is the most common histological type of thyroid carcinoma?

Accepted Answer

Papillary type

Answer

Follicular type

Answer

Anaplastic type

Answer

Medullary type

Question 2

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

Accepted Answer

External branch of superior laryngeal nerve

Answer

Right recurrent laryngeal nerve

Answer

Left recurrent laryngeal nerve

Answer

Right internal laryngeal nerve

Question 3

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

Accepted Answer

Anaplastic carcinoma

Answer

Papillary carcinoma

Answer

Medullary carcinoma

Answer

None of the above

Question 4

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

Accepted Answer

Papillary carcinoma

Answer

Medullary carcinoma

Answer

Follicular carcinoma

Answer

Anaplastic carcinoma

Question 5

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

Accepted Answer

Insufficient preoperative preparation of the patient.

Answer

Excessive manipulation of the thyroid gland during surgery.

Answer

Injury to the recurrent laryngeal nerve.

Answer

Damage to the parathyroid glands.

Question 6

Localization in insulinoma is best with which imaging modality?

Accepted Answer

Selective angiography

Answer

Contrast computerized tomography

Answer

Magnetic resonance imaging

Answer

Somatostatin receptor scintigraphy

Question 7

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?

Accepted Answer

Papillary carcinoma thyroid

Answer

Lateral aberrant thyroid

Answer

Follicular carcinoma thyroid with metastatic lymph nodes

Answer

Anaplastic carcinoma

Question 8

What percentage of cold nodules on thyroid scans are malignant?

Accepted Answer

20%

Answer

5%

Answer

15%

Answer

40%

Question 9

Which of the following is NOT a common complication of hemithyroidectomy?

Accepted Answer

Hypoparathyroidism

Answer

Reactionary hemorrhage

Answer

Recurrent laryngeal nerve palsy

Answer

External laryngeal nerve palsy

Question 10

What is the initial preferred investigation for a thyroid nodule?

Accepted Answer

Thyroid function test

Answer

Fine Needle Aspiration Cytology (FNAC)

Answer

Radionuclide scan

Answer

Ultrasound (USG)

Endocrine Surgery — MCQs

Endocrine Surgery — MCQs

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