Endocrine Surgery — MCQs

Endocrine Surgery Indian Medical PG Practice Questions and MCQs

Question 141: Which of the following levels of lymph nodes are first involved by papillary carcinoma?

A. Level II
B. Level IV
C. Level V
D. Level VI (Correct Answer)

Explanation: **Explanation:** **1. Why Level VI is Correct:** Papillary Thyroid Carcinoma (PTC) is a lymphophilic tumor that typically spreads in a predictable, stepwise fashion via the lymphatic system. The **Level VI (Central Compartment)** lymph nodes are the first-tier nodes for the thyroid gland. This compartment includes the pre-tracheal, para-tracheal, and pre-laryngeal (Delphian) nodes. Because of their immediate anatomical proximity to the thyroid gland, they are the first site of metastasis in approximately 50-80% of patients with PTC. **2. Why Other Options are Incorrect:** * **Level II, III, and IV (Lateral Compartment):** These represent the upper, middle, and lower jugular chains, respectively. While PTC frequently involves these nodes, they are considered **second-tier** drainage sites. Spread to the lateral neck usually occurs after the central compartment is involved, though "skip metastases" can rarely occur. * **Level V (Posterior Triangle):** These nodes are located along the spinal accessory nerve and transverse cervical artery. They are involved much less frequently than Levels II-IV and are almost never the first site of involvement. **3. NEET-PG High-Yield Pearls:** * **Most common site:** The most common specific node involved in the central compartment is the **paratracheal node**. * **Delphian Node:** A positive pre-laryngeal node (Level VI) often indicates extensive subglottic or thyroid involvement and carries a higher risk of further lymphatic spread. * **Management:** While Level VI nodes are the first involved, prophylactic central neck dissection is controversial; however, therapeutic dissection is mandatory if nodes are clinically involved. * **Skip Metastasis:** Defined as lateral node involvement (Levels II-IV) without central node (Level VI) involvement; seen in ~10-20% of cases.

Question 142: The most common cause of hypoparathyroidism after thyroidectomy is:

A. Removal
B. Vascular injury (Correct Answer)
C. Hypertrophy
D. Malignancy

Explanation: **Explanation:** Hypoparathyroidism is the most frequent complication following total thyroidectomy. While several factors can contribute, the primary mechanism is **vascular injury** to the parathyroid glands. **1. Why Vascular Injury is Correct:** The parathyroid glands have a precarious and terminal blood supply. The **inferior thyroid artery (ITA)** is the primary source for both the superior and inferior parathyroid glands in the majority of cases. During thyroid surgery, particularly during the ligation of the ITA or extensive dissection near the posterior capsule, the delicate vessels supplying the glands can be easily damaged, thrombosed, or inadvertently ligated. This leads to **ischemia** and subsequent transient or permanent hypocalcemia, even if the glands remain anatomically in situ. **2. Why Other Options are Incorrect:** * **Removal:** While accidental removal (inadvertent parathyroidectomy) occurs, modern surgical techniques (capsular dissection) aim to identify and preserve the glands. Vascular compromise occurs much more frequently than total physical removal. * **Hypertrophy:** This refers to an increase in cell size, typically seen in secondary hyperparathyroidism, and is not a cause of post-surgical deficiency. * **Malignancy:** While thyroid malignancy may necessitate more radical dissection (increasing the risk of injury), the malignancy itself does not cause hypoparathyroidism; the surgical intervention does. **Clinical Pearls for NEET-PG:** * **Most common site** for an ectopic parathyroid gland: **Thymus** (Inferior parathyroid). * **Hungry Bone Syndrome:** Severe hypocalcemia following surgery for hyperparathyroidism (due to sudden withdrawal of high PTH levels). * **Chvostek’s and Trousseau’s signs:** Classic clinical indicators of post-operative hypocalcemia. * **Surgical Tip:** To preserve blood supply, the inferior thyroid artery should be ligated **distally** (close to the thyroid gland) rather than at its main trunk.

Question 143: What is the gold standard test for diagnosing insulinoma?

A. CT scan
B. Ultrasound (Correct Answer)
C. MRI
D. Arteriography

Explanation: **Explanation:** The diagnosis of insulinoma is established biochemically via the **72-hour supervised fast** (showing Whipple’s triad). Once confirmed, the challenge lies in localization. While the question asks for the "gold standard" among the options provided, it specifically refers to **Intraoperative Ultrasound (IOUS)**, which is widely considered the most sensitive and accurate method for localizing these small, often occult tumors. * **Why Ultrasound is correct:** Intraoperative Ultrasound (IOUS) combined with surgical palpation has a sensitivity of **90-95%**. Since insulinomas are typically small (<2 cm) and often isodense with the pancreas, they are frequently missed by preoperative imaging. IOUS allows the surgeon to visualize the tumor’s relationship to the pancreatic duct and major vessels, making it the definitive "gold standard" for localization during surgery. **Analysis of Incorrect Options:** * **CT Scan (A):** While often the first-line preoperative investigation (Triple-phase CT), its sensitivity is relatively low (approx. 60-70%) for small tumors. * **MRI (B):** Useful for detecting liver metastases but generally less sensitive than EUS or IOUS for small primary insulinomas. * **Arteriography (D):** Historically used (specifically the Calcium Stimulation Test or ASVS), it is invasive and now reserved only for cases where non-invasive imaging and IOUS fail. **High-Yield Clinical Pearls for NEET-PG:** * **Whipple’s Triad:** Hypoglycemic symptoms, low plasma glucose (<55 mg/dL), and relief of symptoms after glucose administration. * **Most Sensitive Preoperative Test:** Endoscopic Ultrasound (EUS). * **Most Sensitive Overall/Intraoperative Test:** IOUS + Palpation. * **Rule of 10s:** 10% are malignant, 10% are multiple, and 10% are associated with **MEN-1 syndrome**. * **Medical Management:** Diazoxide is the drug of choice to inhibit insulin release before surgery.

Question 144: What is the treatment of choice for a cold nodule of the thyroid?

A. Sub-total thyroidectomy
B. Radioactive iodine therapy (I-131)
C. Hemithyroidectomy (Correct Answer)
D. Excision of nodule

Explanation: ### Explanation **1. Why Hemithyroidectomy is the Correct Answer:** A "cold nodule" on a radionuclide scan indicates a lack of iodine uptake, which carries a **15–20% risk of malignancy**. The primary goal of management is to obtain a definitive histopathological diagnosis. While Fine Needle Aspiration Cytology (FNAC) is the initial investigation of choice, if surgery is indicated (due to suspicious cytology or a large symptomatic nodule), **Hemithyroidectomy** (removal of one lobe and the isthmus) is the minimum recommended procedure. It provides an intact specimen for the pathologist to evaluate capsular or vascular invasion (essential for diagnosing Follicular Carcinoma) while preserving the contralateral parathyroid glands and recurrent laryngeal nerve. **2. Why Other Options are Incorrect:** * **Sub-total thyroidectomy (A):** This is an obsolete procedure for nodules. It leaves behind a remnant of thyroid tissue, making re-operation difficult and increasing the risk of recurrence and nerve injury if the nodule proves to be malignant. * **Radioactive iodine therapy (B):** I-131 is used for "hot" nodules (toxic adenomas) or as adjuvant therapy after total thyroidectomy for thyroid cancer. It is ineffective for cold nodules because they do not take up iodine. * **Excision of nodule (D):** Simple "enucleation" is contraindicated in thyroid surgery. It risks breaching the tumor capsule (seeding cells) and has a high rate of recurrence. **3. Clinical Pearls for NEET-PG:** * **Initial Investigation:** Thyroid Function Test (TFT). If TSH is normal/high, proceed to **Ultrasound + FNAC**. * **Best Initial Imaging:** Ultrasonography (USG). * **Gold Standard for Diagnosis:** FNAC (Note: FNAC cannot distinguish between Follicular Adenoma and Carcinoma). * **Hot Nodule:** Usually benign (Toxic Adenoma); risk of malignancy is <1%. * **Cold Nodule:** High suspicion of malignancy; requires surgical evaluation if FNAC is indeterminate (Bethesda III/IV) or suspicious.

Question 145: Which type of thyroid carcinoma is most commonly associated with lymph node metastasis?

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

Explanation: **Explanation:** **Papillary Thyroid Carcinoma (PTC)** is the most common type of thyroid malignancy and is characterized by its **lymphatic route of spread**. Approximately 50–80% of patients with PTC have cervical lymph node involvement at the time of diagnosis. This occurs because PTC cells have a high affinity for the lymphatic channels within the thyroid gland, leading to early spread to the central (Level VI) and lateral neck compartments. **Analysis of Incorrect Options:** * **Follicular Carcinoma:** This tumor typically spreads via the **hematogenous (bloodborne) route**. It commonly metastasizes to the bones and lungs; lymph node involvement is rare (less than 10%). * **Anaplastic Carcinoma:** While highly aggressive and locally invasive, it is characterized by rapid local growth and widespread distant metastasis. While it can involve lymph nodes, its defining feature is rapid destruction of local neck structures. * **Medullary Carcinoma:** This arises from parafollicular C-cells. While it frequently involves lymph nodes (approx. 50%), Papillary carcinoma remains the most common thyroid cancer overall and the one most frequently associated with nodal spread in clinical practice. **High-Yield Clinical Pearls for NEET-PG:** * **Most common thyroid cancer:** Papillary Carcinoma (85%). * **Psammoma bodies:** Laminated calcifications pathognomonic for Papillary Carcinoma. * **Orphan Annie Eye nuclei:** Characteristic nuclear clearing seen in PTC. * **Prognosis:** PTC has an excellent prognosis despite frequent lymph node metastasis. * **Route of Spread Summary:** Papillary = Lymphatic; Follicular = Hematogenous.

Question 146: A patient with a long-standing thyroid nodule is scheduled for subtotal thyroidectomy. What essential pre-operative check should the surgeon perform?

A. Serum Calcium levels
B. Serum PTH assay
C. Indirect Laryngoscopy (Correct Answer)
D. Iodine 131 scan

Explanation: **Explanation:** The correct answer is **Indirect Laryngoscopy (IDL)**. **1. Why Indirect Laryngoscopy is correct:** Before any thyroid or parathyroid surgery, it is mandatory to assess the functional status of the **Recurrent Laryngeal Nerves (RLN)**. Even if the patient is asymptomatic (no hoarseness), one vocal cord may already be paralyzed due to pressure from a long-standing nodule or malignancy. If a surgeon unknowingly damages the only functioning nerve during surgery, it can lead to catastrophic bilateral vocal cord palsy and acute airway obstruction. Documenting pre-operative cord mobility is also essential for medico-legal protection. **2. Why other options are incorrect:** * **Serum Calcium & PTH (Options A & B):** While these are vital *post-operatively* to monitor for accidental parathyroid removal or devascularization, they are not routine pre-operative requirements for a simple thyroid nodule unless medullary carcinoma or primary hyperparathyroidism is suspected. * **Iodine 131 scan (Option D):** This is used to assess the functional status of a nodule (hot vs. cold) or to detect metastases post-thyroidectomy. It is not a mandatory pre-operative safety check for the surgical procedure itself. **Clinical Pearls for NEET-PG:** * **Gold Standard:** While IDL is the traditional method, **Fiberoptic Laryngoscopy** is now preferred for better visualization. * **Nerve Injury:** Unilateral RLN injury causes hoarseness; Bilateral RLN injury causes respiratory distress (stridor) and is a surgical emergency. * **Superior Laryngeal Nerve (SLN):** Injury to the external branch leads to loss of high-pitched voice (the "Amelita Galli-Curci" nerve).

Question 147: What is the mainstay treatment for primary hyperparathyroidism?

A. Bisphosphonates
B. Hormone replacement therapy
C. Calcimimetics
D. Surgery (Correct Answer)

Explanation: **Explanation:** **Primary Hyperparathyroidism (PHPT)** is most commonly caused by a single parathyroid adenoma (85%), followed by multiglandular hyperplasia (10-15%) and parathyroid carcinoma (<1%). **Why Surgery is the Correct Answer:** Surgery (Parathyroidectomy) is the **only definitive and curative treatment** for PHPT. It is indicated for all symptomatic patients (e.g., nephrolithiasis, symptomatic bone disease) and specific asymptomatic patients who meet the "NIH Consensus Criteria" (e.g., age <50, serum calcium >1 mg/dL above normal, T-score ≤ -2.5, or reduced creatinine clearance). Successful surgery results in a cure rate of over 95-98%. **Why Other Options are Incorrect:** * **A. Bisphosphonates:** These are used to increase bone mineral density in patients who cannot undergo surgery, but they do not treat the underlying hypercalcemia or the parathyroid pathology. * **B. Hormone Replacement Therapy (HRT):** While estrogen can reduce bone resorption in postmenopausal women, it is not a primary treatment for PHPT and carries risks like thromboembolism. * **C. Calcimimetics (e.g., Cinacalcet):** These drugs lower serum calcium by increasing the sensitivity of calcium-sensing receptors. They are used for medical management in patients who are poor surgical candidates or have parathyroid carcinoma, but they are not curative. **High-Yield Clinical Pearls for NEET-PG:** * **Gold Standard Localization:** Sestamibi Scan (Technetium-99m) combined with Ultrasound. * **Intraoperative Monitoring:** The **Miami Criterion** (a >50% drop in intraoperative PTH 10 minutes after excision) confirms a successful surgery. * **Most Common Cause:** Solitary Adenoma (usually in the inferior parathyroid gland). * **Hungry Bone Syndrome:** A common post-operative complication characterized by profound hypocalcemia, hypophosphatemia, and hypomagnesemia.

Question 148: What is the primary indication for surgical intervention in cases of thyroiditis?

A. Prevention of cancerous degeneration
B. Relief of neck and ear pain
C. Alleviation of tracheal or esophageal compression (Correct Answer)
D. Treatment of toxic reactions

Explanation: **Explanation:** Thyroiditis is primarily a medical condition managed with anti-inflammatory drugs, steroids, or thyroid hormone replacement. Surgery is rarely indicated and is never the first-line treatment. **Why Option C is Correct:** The primary indication for surgery in thyroiditis (specifically **Riedel’s Thyroiditis** or occasionally Hashimotos with a large goiter) is the **alleviation of pressure symptoms**. When the thyroid becomes intensely fibrotic or enlarged, it can compress the trachea (causing stridor/dyspnea) or the esophagus (causing dysphagia). In Riedel’s thyroiditis, a **wedge resection of the isthmus** (Isthmusectomy) is performed specifically to relieve tracheal compression. **Why Other Options are Incorrect:** * **Option A:** Thyroiditis (like Hashimoto’s) is associated with an increased risk of B-cell lymphoma, but prophylactic surgery is not indicated to prevent malignancy. * **Option B:** Pain in Subacute (De Quervain’s) thyroiditis is managed medically with NSAIDs or corticosteroids. Surgery does not play a role in pain management. * **Option D:** "Toxic reactions" (Hyperthyroidism) in thyroiditis are usually transient (release of pre-formed hormones) and are managed with Beta-blockers, not surgery or anti-thyroid drugs. **High-Yield Clinical Pearls for NEET-PG:** * **Riedel’s Thyroiditis:** Characterized by "woody" or "stony-hard" thyroid due to dense fibrosis that extends beyond the capsule into adjacent neck structures. * **Surgery in Riedel’s:** The goal is not total thyroidectomy (due to loss of tissue planes and risk to nerves/parathyroids) but a simple **isthmusectomy** to free the trachea. * **De Quervain’s Thyroiditis:** Most common cause of a **painful** thyroid gland; usually follows a viral upper respiratory infection. * **Hashimoto’s Thyroiditis:** Most common cause of hypothyroidism; associated with **Anti-TPO antibodies** and Hürthle cells on histology.

Question 149: A 35-year-old female presents with a solitary thyroid nodule. Fine needle aspiration cytology (FNAC) reveals "Orphan Annie eyed nuclei." There is no lymph node involvement. What is the most appropriate management for this patient?

A. Total thyroidectomy
B. Total thyroidectomy with central lymph node dissection
C. Hemi thyroidectomy (Correct Answer)
D. Hemi thyroidectomy with central lymph node dissection

Explanation: **Explanation:** The presence of **"Orphan Annie eyed nuclei"** (large, pale, overlapping nuclei with peripheral chromatin) is pathognomonic for **Papillary Thyroid Carcinoma (PTC)**, the most common thyroid malignancy. **1. Why Hemithyroidectomy is correct:** According to the latest **American Thyroid Association (ATA) guidelines**, for low-risk differentiated thyroid cancers (PTC) that are **solitary, <4 cm in size, and have no evidence of extrathyroidal extension or lymph node involvement (cN0)**, a thyroid lobectomy (hemithyroidectomy) is considered sufficient and appropriate management. This approach minimizes the risk of complications like recurrent laryngeal nerve injury and permanent hypoparathyroidism while maintaining excellent oncological outcomes. **2. Why other options are incorrect:** * **Total Thyroidectomy (Option A):** While previously the standard, it is now reserved for tumors >4 cm, bilateral disease, gross extrathyroidal extension, or patients with high-risk features/metastases. * **Total Thyroidectomy with Central Lymph Node Dissection (Option B):** This is indicated if there is clinical or radiological evidence of lymphadenopathy (cN1). Prophylactic central neck dissection is controversial and not routinely recommended for low-risk T1/T2 tumors. * **Hemithyroidectomy with Central Lymph Node Dissection (Option D):** Lymph node dissection is generally performed in conjunction with total thyroidectomy if nodes are involved; it is not standard practice to perform a dissection alongside a simple lobectomy in a cN0 neck. **High-Yield Clinical Pearls for NEET-PG:** * **Psammoma bodies:** Laminated calcifications often seen in PTC (60% of cases). * **Prognosis:** PTC has an excellent 10-year survival rate (>90%). * **Spread:** PTC primarily spreads via **lymphatics** (unlike Follicular CA, which spreads hematogenously). * **Most common site of metastasis:** Level VI (Central compartment) lymph nodes.

Question 150: Which of the following statements is NOT true regarding medullary carcinoma of the thyroid?

A. Hereditary
B. Secretes calcitonin
C. Hormone dependent (Correct Answer)
D. Amyloid stroma

Explanation: **Explanation:** Medullary Carcinoma of the Thyroid (MTC) arises from the **parafollicular C-cells**, which are neuroendocrine cells derived from the neural crest. Unlike papillary and follicular carcinomas, which arise from follicular cells and are stimulated by Thyroid Stimulating Hormone (TSH), MTC is **not hormone-dependent**. Therefore, TSH suppression therapy is ineffective in managing MTC. **Analysis of Options:** * **Hormone dependent (Correct Answer):** This is the false statement. MTC cells do not have TSH receptors; thus, their growth is independent of TSH levels. * **Hereditary:** Approximately 20–25% of MTC cases are hereditary, occurring as part of **MEN 2A, MEN 2B**, or Familial MTC (FMTC) syndromes, usually associated with the **RET proto-oncogene** mutation. * **Secretes calcitonin:** Calcitonin is the primary tumor marker for MTC. It is used for diagnosis, screening, and monitoring recurrence. Carcinoembryonic antigen (CEA) is also often elevated. * **Amyloid stroma:** A classic histological hallmark of MTC is the presence of acellular amyloid deposits in the stroma, which represent pro-calcitonin fibrils. These stain positive with **Congo Red** (showing apple-green birefringence). **High-Yield Clinical Pearls for NEET-PG:** * **Spread:** MTC spreads via both lymphatic and hematogenous routes. * **Treatment:** The definitive treatment is **Total Thyroidectomy** with central compartment neck dissection. * **Screening:** In hereditary cases, family members should be screened for the **RET mutation**. Prophylactic thyroidectomy is indicated if the mutation is present. * **Associated Conditions:** Always rule out **Pheochromocytoma** (part of MEN 2) before surgery to prevent a hypertensive crisis.

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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