Endocrine Surgery — MCQs

Endocrine Surgery Indian Medical PG Practice Questions and MCQs

Question 171: Prophylactic thyroidectomy is indicated for which of the following conditions?

A. Hashimoto's thyroiditis
B. Multiple Endocrine Neoplasia (MEN) 2B syndrome (Correct Answer)
C. Riedel's thyroiditis
D. Graves' disease

Explanation: **Explanation:** **Why Option B is Correct:** Prophylactic thyroidectomy is the standard of care for patients with **Multiple Endocrine Neoplasia (MEN) 2A and 2B** due to the 100% penetrance of **Medullary Thyroid Carcinoma (MTC)**. In MEN 2B, MTC is particularly aggressive, appearing earlier in life and metastasizing rapidly. Current guidelines (ATA) recommend prophylactic total thyroidectomy **within the first year of life** (ideally by 6 months) for infants identified with the *RET* proto-oncogene mutation associated with MEN 2B. **Why Other Options are Incorrect:** * **A. Hashimoto’s Thyroiditis:** This is an autoimmune condition managed primarily with levothyroxine. Surgery is only indicated if there is a suspicion of lymphoma or compressive symptoms. * **C. Riedel’s Thyroiditis:** A rare systemic IgG4-related sclerosing disease. Management is medical (Tamoxifen, Steroids). Surgery is technically difficult due to dense fibrosis and is reserved only for relieving tracheal compression (wedge resection of the isthmus). * **D. Graves’ Disease:** An autoimmune hyperthyroidism. While thyroidectomy is a definitive treatment option (especially for large goiters or suspicious nodules), it is **therapeutic**, not prophylactic. **High-Yield Clinical Pearls for NEET-PG:** * **MEN 2A:** Prophylactic thyroidectomy is recommended by **age 5**. * **Screening:** The most sensitive screening tool for MEN 2 syndromes is genetic testing for **RET proto-oncogene** mutations. * **Tumor Marker:** Post-operative monitoring for MTC recurrence is done via serum **Calcitonin** and CEA levels. * **Order of Surgery:** In MEN 2 patients, always rule out or treat **Pheochromocytoma** before performing thyroid surgery to prevent a hypertensive crisis.

Question 172: What is the treatment for parathyroid adenoma?

A. Calcitonin and steroid
B. Removal of the adenoma (Correct Answer)
C. Total parathyroidectomy and implantation in the arm
D. Total parathyroidectomy

Explanation: **Explanation:** **1. Why Option B is Correct:** The primary cause of Primary Hyperparathyroidism (PHPT) in approximately 85-90% of cases is a **solitary parathyroid adenoma**. The definitive treatment is the surgical excision of the specific enlarged gland (Adenoma). Once the hyperfunctioning tissue is removed, the remaining normal parathyroid glands (which were suppressed by high calcium levels) regain function, restoring calcium homeostasis. In modern practice, this is often done via **Minimally Invasive Parathyroidectomy (MIP)** if the adenoma is localized pre-operatively using Sestamibi scans or ultrasound. **2. Why Other Options are Incorrect:** * **Option A:** Calcitonin and steroids are used in the acute management of severe hypercalcemia (hypercalcemic crisis) to lower serum calcium levels temporarily. They do not treat the underlying surgical pathology (the adenoma). * **Option C:** Total parathyroidectomy with autotransplantation (usually into the brachioradialis muscle) is the treatment of choice for **secondary hyperparathyroidism** or **multiglandular hyperplasia** (e.g., MEN 1 or MEN 2A), not a solitary adenoma. * **Option D:** Total parathyroidectomy without reimplantation would lead to permanent hypocalcemia and hypoparathyroidism, requiring lifelong calcium and Vitamin D supplementation. **3. NEET-PG High-Yield Pearls:** * **Gold Standard Investigation:** Sestamibi Scan (Technetium-99m) is the most sensitive for localizing an adenoma. * **Intraoperative Confirmation:** The **Miami Criterion** is used—a >50% drop in intraoperative Parathyroid Hormone (ioPTH) levels 10 minutes after excision confirms a successful surgery. * **Hungry Bone Syndrome:** A common post-operative complication characterized by profound hypocalcemia, hypophosphatemia, and hypomagnesemia as the "starved" bones rapidly uptake minerals. * **Most common location:** The inferior parathyroid glands are more variable in location and are the most common site for ectopic adenomas (often in the thymus).

Question 173: A 30-year-old lady who underwent near-total thyroidectomy for papillary carcinoma two years ago is found to have multiple, discrete, mobile, left deep cervical lymph nodes measuring 1 to 1.5 cm in size during follow-up. What is the ideal treatment for this patient?

A. Iodine 131 ablation (Correct Answer)
B. External irradiation to the neck
C. Thyroxine therapy
D. Modified radical neck dissection

Explanation: **Explanation:** The management of recurrent or metastatic Papillary Thyroid Carcinoma (PTC) depends on the size and extent of the disease. In this patient, the presence of multiple, small (1–1.5 cm), discrete, and mobile lymph nodes two years after a near-total thyroidectomy indicates regional recurrence. **1. Why Iodine-131 (RAI) Ablation is Correct:** Papillary carcinoma is an iodine-concentrating tumor. Following a near-total or total thyroidectomy, any residual thyroid tissue or microscopic/small-volume nodal disease is best managed with **Radioactive Iodine (I-131) therapy**. It effectively targets and destroys occult or small metastatic deposits that are difficult to clear surgically. In clinical practice, if nodes are small and multiple, RAI is the preferred first-line systemic approach to achieve "biochemical cure." **2. Why Other Options are Incorrect:** * **Modified Radical Neck Dissection (MRDN):** This is indicated for clinically significant, bulky, or fixed lymphadenopathy (usually >2 cm) or when nodes fail to respond to RAI. For small, mobile nodes, surgery is often deferred in favor of RAI to avoid the morbidity of re-exploration. * **Thyroxine Therapy:** While suppressive doses of T4 are mandatory post-thyroidectomy to keep TSH low, it is an adjuvant treatment, not a primary treatment for active nodal recurrence. * **External Irradiation:** This is reserved for palliative care in elderly patients with unresectable, iodine-refractory disease or rapidly progressive anaplastic transformation. **Clinical Pearls for NEET-PG:** * **Investigation of Choice for Recurrence:** Serum Thyroglobulin (Tg) levels and Neck Ultrasound. * **Gold Standard for Nodal Mapping:** Contrast-enhanced CT (without IV contrast if RAI is planned) or USG-guided FNAC. * **RAI Requirement:** Patients must have a high TSH (>30 mIU/L) and a low-iodine diet before I-131 administration for maximum uptake.

Question 174: What is the primary treatment for Medullary Carcinoma of the thyroid?

A. Surgery and radiotherapy
B. Radiotherapy and chemotherapy
C. Surgery only (Correct Answer)
D. Radioiodine ablation

Explanation: **Explanation:** Medullary Thyroid Carcinoma (MTC) arises from the **parafollicular C-cells**, which are neuroendocrine in origin and derived from the neural crest. Unlike follicular cells, C-cells do not concentrate iodine; therefore, MTC is inherently resistant to radioactive iodine therapy and is generally poorly responsive to chemotherapy and external beam radiation. **1. Why "Surgery only" is correct:** Surgery is the only curative treatment for MTC. The standard of care is **Total Thyroidectomy** with **Central Compartment Neck Dissection (Level VI)**. This is because MTC is frequently multicentric (especially in familial cases/MEN 2 syndromes) and has a high propensity for early lymphatic spread. **2. Why other options are incorrect:** * **Radiotherapy and Chemotherapy (A & B):** MTC is relatively radioresistant and chemoresistant. These modalities are reserved only for palliative care or unresectable local recurrence, not as primary treatment. * **Radioiodine Ablation (D):** This is a major "distractor." Since MTC originates from C-cells (not follicular cells), it does not take up Iodine-131. Radioiodine is used for Differentiated Thyroid Cancers (Papillary and Follicular) but has **no role** in MTC. **Clinical Pearls for NEET-PG:** * **Tumor Marker:** Serum **Calcitonin** (used for diagnosis, screening, and monitoring recurrence) and CEA. * **Genetic Screening:** All patients with MTC must be screened for **RET proto-oncogene** mutations to rule out MEN 2A/2B. * **Pre-op Rule Out:** Always exclude **Pheochromocytoma** (via urinary/plasma metanephrines) before surgery to prevent a hypertensive crisis during anesthesia. * **Prophylactic Surgery:** In RET mutation carriers, prophylactic thyroidectomy is performed based on the specific codon mutation risk.

Question 175: Which of the following is not a feature of Riedel thyroiditis?

A. Fibrosing condition
B. Fibrosing condition
C. Fine needle aspiration cytology (FNAC) is the investigation of choice (Correct Answer)
D. Associated with retroperitoneal fibrosis

Explanation: **Explanation:** Riedel thyroiditis is a rare, chronic inflammatory disease characterized by the replacement of thyroid parenchyma with dense fibrous tissue. It is now considered a manifestation of **IgG4-related systemic disease**. **Why Option C is correct:** Fine Needle Aspiration Cytology (FNAC) is **not** the investigation of choice because the thyroid gland becomes extremely hard ("woody" or "iron-hard"). The dense fibrosis makes it difficult to aspirate sufficient cellular material, often resulting in a non-diagnostic or "dry tap." The definitive diagnosis requires an **open wedge biopsy** to confirm the presence of dense fibrous tissue extending beyond the thyroid capsule into adjacent structures. **Why other options are incorrect:** * **Options A & B (Fibrosing condition):** These are characteristic features. Riedel thyroiditis is defined by intense fibrosis that destroys the thyroid and infiltrates surrounding muscles, nerves, and the trachea. * **Option D (Associated with retroperitoneal fibrosis):** This is a classic association. As part of the IgG4-related spectrum, it is frequently linked with other systemic fibrosing conditions, including retroperitoneal fibrosis (Ormond’s disease), sclerosing cholangitis, and mediastinal fibrosis. **High-Yield Clinical Pearls for NEET-PG:** * **Clinical Presentation:** A "stony hard," painless, fixed goiter that can cause obstructive symptoms (dyspnea, dysphagia, hoarseness). * **Differential Diagnosis:** Must be distinguished from Anaplastic Carcinoma (which also presents as a hard, fixed mass but usually in older patients with rapid growth). * **Treatment:** **Tamoxifen** and **Corticosteroids** are the mainstays of medical management. Surgery is limited to wedge resection of the thyroid isthmus to relieve tracheal compression. * **Thyroid Function:** Most patients are euthyroid, but 30% may develop hypothyroidism.

Question 176: Which type of thyroid cancer is characterized by high aggressiveness and lethality?

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

Explanation: **Explanation:** **Anaplastic Thyroid Carcinoma (ATC)** is the correct answer because it is one of the most aggressive and lethal solid tumors in humans. Unlike differentiated thyroid cancers, ATC is characterized by rapid local invasion of neck structures (trachea, esophagus, and vessels) and early distant metastasis. It typically presents in elderly patients (6th–7th decade) as a rapidly enlarging neck mass, often leading to death within 6 months of diagnosis due to airway obstruction or systemic disease. **Analysis of Incorrect Options:** * **Papillary Thyroid Carcinoma (PTC):** This is the most common type of thyroid cancer. It has an excellent prognosis with a 10-year survival rate exceeding 90%. It typically spreads via lymphatics. * **Follicular Thyroid Carcinoma (FTC):** This is the second most common type. While more aggressive than Papillary (due to hematogenous spread to bones and lungs), it still carries a very favorable prognosis compared to Anaplastic. * **Medullary Thyroid Carcinoma (MTC):** Arising from parafollicular C-cells, it is of intermediate aggressiveness. While more lethal than PTC/FTC, it does not match the rapid fatality of ATC. **High-Yield Clinical Pearls for NEET-PG:** * **Histology:** ATC shows spindle, polygonal, or giant cells with frequent mitoses; it lacks any follicular or papillary architecture. * **Transformation:** ATC often arises from a pre-existing long-standing differentiated thyroid cancer (usually Follicular) or goiter. * **Markers:** ATC is often negative for Thyroglobulin and TTF-1, making diagnosis reliant on clinical presentation and biopsy. * **Treatment:** Most cases are unresectable at the time of diagnosis; palliative tracheostomy and radiotherapy are often the only options.

Question 177: Surgical removal of adrenal adenoma is indicated when their size is more than:

A. 2 cm
B. 4 cm (Correct Answer)
C. 6 cm
D. 10 cm

Explanation: The management of adrenal incidentalomas (incidentally discovered adrenal masses) is a high-yield topic in surgical endocrinology. The primary concern with an asymptomatic adrenal mass is the risk of **adrenocortical carcinoma (ACC)**. ### **Why 4 cm is the Correct Answer** The size of the adrenal mass is the most reliable predictor of malignancy. Statistical data shows: * Lesions **<4 cm** have a very low risk of malignancy (approx. 2%). * Lesions **4–6 cm** have an intermediate risk (approx. 6%). * Lesions **>6 cm** have a high risk (up to 25%). Current clinical guidelines (including AACE/AAES) recommend surgical resection for non-functional adrenal masses **≥4 cm** because the risk of missing a localized carcinoma outweighs the risks of surgery. ### **Analysis of Incorrect Options** * **A (2 cm):** Most masses of this size are benign adenomas. Surgery is only indicated if the mass is biochemically active (e.g., Conn’s syndrome or Cushing’s). * **C (6 cm):** While 6 cm is a definitive threshold where malignancy risk increases sharply, the "surgical trigger" is set lower at 4 cm to ensure early intervention for potentially curable cancers. * **D (10 cm):** Masses of this size are highly suspicious for malignancy and often present with local invasion or metastasis. ### **High-Yield Clinical Pearls for NEET-PG** 1. **Biochemical Workup:** Every adrenal incidentaloma, regardless of size, must be screened for functionality (24-hr urinary metanephrines, low-dose dexamethasone suppression test, and plasma aldosterone/renin ratio if hypertensive). 2. **Imaging Characteristics:** A "benign" profile on CT includes a size <4 cm, smooth borders, and **low attenuation (<10 Hounsfield Units)** due to high lipid content. 3. **Biopsy Contraindication:** Never perform a Fine Needle Aspiration (FNA) of an adrenal mass until **Pheochromocytoma** is ruled out, as it can precipitate a lethal hypertensive crisis. 4. **Growth Rate:** If a mass <4 cm grows by **>1 cm** during follow-up, surgical removal is indicated.

Question 178: A 26-year-old woman presents with a palpable thyroid nodule. Needle biopsy demonstrates amyloid in the stroma of the lesion. A cervical lymph node is palpable on the same side as the lesion. What is the preferred treatment?

A. Removal of the involved node, the isthmus, and the enlarged lymph node.
B. Removal of the involved lobe, the isthmus, a portion of the opposite lobe, and the enlarged lymph node.
C. Total thyroidectomy and modified neck dissection on the side of the enlarged lymph node. (Correct Answer)
D. Total thyroidectomy and irradiation of the cervical lymph nodes.

Explanation: ### Explanation **1. Understanding the Diagnosis** The presence of **amyloid in the stroma** on needle biopsy is the pathognomonic histological feature of **Medullary Thyroid Carcinoma (MTC)**. MTC arises from the parafollicular C-cells (which produce calcitonin) and is characterized by extracellular amyloid deposits derived from pro-calcitonin. **2. Why Option C is Correct** MTC is a more aggressive tumor than differentiated thyroid cancers (like papillary or follicular) and frequently presents with early lymph node metastasis. * **Total Thyroidectomy:** MTC is often multicentric (especially in familial cases), necessitating the removal of the entire gland. * **Modified Radical Neck Dissection (MRND):** Since a cervical lymph node is already palpable (indicating metastasis), a formal neck dissection is mandatory. MTC is **not** sensitive to radioiodine or external beam radiation; therefore, surgical clearance is the only curative intent. **3. Why Other Options are Wrong** * **Options A & B:** Hemithyroidectomy or subtotal thyroidectomy are inadequate for MTC because they leave behind thyroid tissue prone to recurrence and do not address the systemic nature of C-cell hyperplasia or multicentricity. * **Option D:** MTC is **radioresistant**. Irradiation is not a primary treatment for cervical lymphadenopathy in thyroid cancer; surgical excision (MRND) is the standard of care. **Clinical Pearls for NEET-PG:** * **Marker:** Serum **Calcitonin** is used for diagnosis and monitoring recurrence; **CEA** is a secondary marker. * **Genetics:** 25% are familial (MEN 2A/2B syndrome). Always screen for **Pheochromocytoma** (using urinary metanephrines) before thyroid surgery to prevent intraoperative hypertensive crisis. * **RET Proto-oncogene:** Mutations are associated with MTC. * **Stain:** Amyloid in MTC stains positive with **Congo Red** and shows apple-green birefringence under polarized light.

Question 179: A patient presents with a small solitary nodule in the right lobe of the thyroid. FNAC shows follicular adenoma. What is the best surgical management?

A. Enucleation
B. Subtotal thyroidectomy
C. Right hemithyroidectomy (Correct Answer)
D. Near-total thyroidectomy

Explanation: ### **Explanation** The core challenge in managing a follicular lesion on Fine Needle Aspiration Cytology (FNAC) is that **FNAC cannot distinguish between a benign follicular adenoma and a malignant follicular carcinoma.** This distinction requires histological evidence of capsular or vascular invasion, which can only be determined by examining the entire specimen after surgical excision. **Why Right Hemithyroidectomy is Correct:** For a solitary nodule suspicious of a follicular neoplasm, **Hemithyroidectomy (Lobectomy + Isthmusectomy)** is the standard diagnostic and therapeutic procedure. It ensures the entire nodule is removed with an intact capsule for histopathological examination. If pathology confirms an adenoma, the patient is cured. If it reveals carcinoma, the patient may require a completion thyroidectomy depending on the tumor size and features. **Analysis of Incorrect Options:** * **A. Enucleation:** This involves shelling out the nodule. It is contraindicated because it risks rupturing the capsule (spilling potential malignant cells) and provides inadequate margins for assessing vascular/capsular invasion. * **B. Subtotal thyroidectomy:** This leaves a portion of the thyroid tissue on both sides. It is generally obsolete in modern oncology because it makes re-operation difficult and provides an incomplete oncological clearance. * **C. Near-total thyroidectomy:** This is overly aggressive for a solitary nodule that has not yet been confirmed as malignant. It unnecessarily increases the risk of recurrent laryngeal nerve injury and hypoparathyroidism. **High-Yield Clinical Pearls for NEET-PG:** * **Bethesda Category IV:** Follicular neoplasms are classified as Bethesda IV. The risk of malignancy is approximately 15–30%. * **Frozen Section:** Generally **not useful** for follicular lesions because the pathologist needs to examine multiple sections of the capsule to rule out invasion, which cannot be done reliably during surgery. * **Hürthle Cell Lesions:** Managed similarly to follicular neoplasms (Hemithyroidectomy) as they also require histological assessment for malignancy.

Question 180: Which of the following are indications for surgery in a case of thyroid swelling?

A. Cosmetic, pressure symptoms, and myxedema
B. Cosmetic, pressure symptoms, and swelling with symptoms (Correct Answer)
C. Cosmetic, pressure symptoms, pain, and swelling with symptoms
D. All are indications for surgery

Explanation: ### Explanation The management of thyroid swellings (goiters) depends on the clinical presentation, functional status, and cytological findings. Surgery is indicated when the swelling causes physical distress, functional abnormalities, or aesthetic concerns. **1. Why Option B is Correct:** The standard indications for thyroidectomy include: * **Pressure Symptoms:** Large goiters can compress the trachea (causing dyspnea/stridor) or the esophagus (causing dysphagia). This is a definitive indication for surgical decompression. * **Cosmetic Reasons:** A large, visible neck mass can cause significant psychological distress or social inhibition for the patient. * **Swelling with Symptoms (Toxic Goiter):** In cases of hyperthyroidism (e.g., Graves' disease or Toxic Multinodular Goiter) where medical management fails, is contraindicated, or if there is a suspicion of malignancy, surgery is indicated. **2. Why Other Options are Incorrect:** * **Myxedema (Option A & D):** Myxedema is a state of severe hypothyroidism. Surgery is **contraindicated** in untreated hypothyroid states due to the risk of myxedema coma and poor surgical outcomes. Hypothyroidism is managed medically with Levothyroxine. * **Pain (Option C):** While pain can occur in conditions like De Quervain’s thyroiditis or hemorrhage into a cyst, it is rarely a primary indication for surgery. Thyroiditis is usually managed with NSAIDs or steroids, not surgery. **3. High-Yield Clinical Pearls for NEET-PG:** * **Absolute Indication:** Suspicion of malignancy (Bethesda Category V and VI) is the most critical indication for surgery. * **Retrosternal Goiter:** Most retrosternal goiters require surgery (even if asymptomatic) because they are likely to cause future airway compromise and cannot be monitored effectively by palpation. * **Pre-op Requirement:** In toxic goiters, the patient must be made **euthyroid** using antithyroid drugs (Carbimazole/PTU) and Beta-blockers before surgery to prevent a **Thyroid Storm**. * **Lugol’s Iodine:** Often given 10 days pre-operatively in Graves' disease to decrease the vascularity of the gland.

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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