Endocrine Surgery Practice Questions

Q: In pheochromocytoma, which of the following is NOT part of the 'rule of 10'?

10% are symptomatic. ### Explanation Pheochromocytoma is a catecholamine-secreting tumor arising from chromaffin cells of the adrenal medulla. Traditionally, it is described by the **"Rule of 10s,"** which helps clinicians remember its epidemiological distribution. **Why Option D is the correct answer:** The statement "10% are symptomatic" is **incorrect** because the vast majority of patients with pheochromocytoma are symptomatic. The classic triad consists of episodic headache, sweating (diaphoresis), and palpitations, often accompanied by hypertension. If only 10% were symptomatic, the tumor would rarely be diagnosed clinically. **Analysis of the "Rule of 10s" (Incorrect Options):** * **10% are Bilateral (Option A):** Most cases are sporadic and unilateral; however, roughly 10% occur on both sides (this percentage is significantly higher in familial syndromes like MEN 2A/2B). * **10% are Malignant (Option B):** About 90% are benign. Malignancy is defined not by histology, but by the presence of tumor cells in non-chromaffin sites (e.g., bone, liver, lungs). * **10% are Extra-adrenal (Option C):** These are known as **paragangliomas**. The most common extra-adrenal site is the Organ of Zuckerkandl (near the origin of the inferior mesenteric artery). **High-Yield Clinical Pearls for NEET-PG:** 1. **Rule of 10s Update:** Recent genetics suggest that up to **30-40%** of cases may be hereditary (associated with *RET, VHL, NF1,* and *SDH* mutations), challenging the traditional "10% familial" rule. 2. **Diagnosis:** The best initial screening test is **24-hour urinary fractionated metanephrines** or plasma free metanephrines. 3. **Pre-operative Management:** Always follow the rule: **Alpha-blockade first** (e.g., Phenoxybenzamine) for 10-14 days, followed by Beta-blockade to prevent a hypertensive crisis. 4. **10% occur in children.**

Q: Thyroid storm after operation is typically due to which of the following factors?

Inadequate control of preoperative hyperthyroidism. **Explanation:** **Thyroid storm** is a life-threatening exacerbation of hyperthyroidism characterized by hyperpyrexia, tachycardia, and altered mental status. In the context of surgery, the primary cause is the **inadequate preoperative control of hyperthyroidism**. When a patient with uncontrolled Graves' disease or toxic multinodular goiter undergoes surgery, the physical stress and surgical manipulation of the gland trigger a massive release of pre-formed thyroid hormones ($T_3$ and $T_4$) into the circulation, leading to a hypermetabolic crisis. **Analysis of Options:** * **Option A (Correct):** Achieving a **euthyroid state** before surgery is the gold standard for prevention. This is typically done using Antithyroid drugs (Propylthiouracil/Methimazole) and Lugol’s iodine (to decrease vascularity). * **Option B:** Massive bleeding leads to hypovolemic shock, not a hypermetabolic thyroid crisis. * **Option C:** Recurrent laryngeal nerve injury causes hoarseness (unilateral) or airway obstruction (bilateral), but does not trigger hormonal surges. * **Option D:** While systemic infection can *precipitate* a thyroid storm in a medical setting, the specific "post-thyroidectomy" storm is almost always attributed to poor preoperative preparation. **Clinical Pearls for NEET-PG:** * **Timing:** Thyroid storm typically occurs **6–18 hours** postoperatively. * **Management:** Treatment includes **Beta-blockers** (Propranolol to control symptoms and inhibit peripheral $T_4$ to $T_3$ conversion), **PTU**, **IV Sodium Iodide** (given 1 hour after PTU), and **Corticosteroids** (to prevent adrenal exhaustion and inhibit $T_4 \to T_3$ conversion). * **Aspirin is contraindicated** in thyroid storm as it displaces thyroid hormones from thyroid-binding globulin (TBG), increasing free hormone levels. Use Paracetamol for fever instead.

Q: In which of the following thyroid malignancies does the size of the primary lesion have a greater impact on prognosis than lymph node metastasis?

Papillary carcinoma. **Explanation:** In **Papillary Thyroid Carcinoma (PTC)**, the most common thyroid malignancy, the presence of regional lymph node metastasis is frequent (occurring in up to 50-80% of cases) but surprisingly has a **minimal impact on overall survival**, especially in younger patients. According to the **AMES** (Age, Metastasis, Extent, Size) and **MACIS** scoring systems, the **size of the primary tumor** (>4 cm) and the age of the patient are far more significant prognostic indicators than nodal involvement. While nodal spread increases the risk of local recurrence, it does not significantly decrease long-term survival rates. **Analysis of Incorrect Options:** * **B. Follicular Carcinoma:** This tumor spreads primarily via the **hematogenous route** (bloodstream) rather than lymphatics. Therefore, lymph node metastasis is rare, and prognosis is dictated by vascular invasion and distant metastasis (bone/lung). * **C. Medullary Carcinoma:** Derived from parafollicular C-cells, this tumor is more aggressive than PTC. The presence of lymph node metastasis here is a **strong negative prognostic factor** and significantly correlates with a decrease in survival and higher recurrence rates. * **D. Anaplastic Carcinoma:** This is one of the most lethal human malignancies. The prognosis is universally poor regardless of size or nodal status, as most patients present with locally advanced disease or distant metastasis at the time of diagnosis. **High-Yield Clinical Pearls for NEET-PG:** * **Most common thyroid cancer:** Papillary Carcinoma. * **Characteristic Histology (PTC):** Orphan Annie eye nuclei, Psammoma bodies, and Coffee bean nuclei (nuclear grooves). * **Route of Spread:** Papillary = Lymphatic; Follicular = Hematogenous. * **Prognostic Systems:** Remember **AMES** and **MACIS** for PTC; size and age are the heavy hitters, not nodes.

Q: A 29-year-old woman underwent a thyroidectomy. Postoperatively, the patient presented with hoarseness. Which of the following nerves was most likely injured during the operation?

Recurrent laryngeal. **Explanation:** The patient’s presentation of **hoarseness** following thyroidectomy is a classic sign of **Recurrent Laryngeal Nerve (RLN)** injury. **1. Why Recurrent Laryngeal Nerve is Correct:** The RLN provides motor supply to all intrinsic muscles of the larynx except the cricothyroid. It also provides sensory innervation to the larynx below the vocal cords. * **Unilateral injury:** Results in the vocal cord assuming a paramedian position, leading to **hoarseness** and a weak, breathy voice. * **Bilateral injury:** Can lead to airway obstruction and stridor, often requiring an emergency tracheostomy. The RLN is most vulnerable during the ligation of the **inferior thyroid artery**, as it closely approximates the artery near the lower pole of the thyroid. **2. Analysis of Incorrect Options:** * **External Laryngeal Nerve (ELN):** This nerve supplies the **cricothyroid muscle**. Injury (usually during ligation of the superior thyroid artery) leads to an inability to tense the vocal cords, resulting in a **loss of high-pitched tones** and easy vocal fatigue, but not frank hoarseness. * **Internal Laryngeal Nerve:** This is a purely **sensory** nerve supplying the larynx above the vocal cords. Injury results in a loss of the cough reflex, increasing the risk of aspiration, but does not affect voice quality. * **Superior Laryngeal Nerve (SLN):** This nerve divides into the internal and external branches. While "SLN injury" is a broad term, the specific motor deficit causing voice changes is attributed to its external branch. **3. NEET-PG High-Yield Pearls:** * **Most common nerve injured** in thyroidectomy: Recurrent Laryngeal Nerve. * **Nerve at risk during Superior Thyroid Artery ligation:** External Laryngeal Nerve. * **Nerve at risk during Inferior Thyroid Artery ligation:** Recurrent Laryngeal Nerve. * **Standard of Care:** Intraoperative nerve monitoring is increasingly used to identify and preserve these nerves.

Q: Which of the following is FALSE regarding follicular thyroid cancer?

It is not encapsulated.. **Explanation** Follicular Thyroid Carcinoma (FTC) is the second most common thyroid malignancy. Understanding its pathological and clinical behavior is crucial for NEET-PG. **Why Option C is the Correct (False) Statement:** Unlike Papillary Thyroid Carcinoma (PTC), which is often unencapsulated, **Follicular Thyroid Carcinoma is typically encapsulated.** The diagnosis of malignancy depends entirely on demonstrating **capsular invasion** or **vascular invasion** on histopathology. If the tumor is confined within the capsule without invasion, it is classified as a Follicular Adenoma. **Analysis of Other Options:** * **Option A:** FTC is indeed more prevalent in iodine-deficient (endemic) areas. While thyroid cancers are more common in females, the prognosis is often more aggressive (more malignant) in females and older age groups. * **Option B:** This is a classic high-yield fact. **FNAC cannot differentiate between follicular adenoma and carcinoma** because it only evaluates cellular morphology, not the architectural integrity of the capsule or blood vessels. * **Option D:** FTC typically presents in an older age group compared to PTC, with a peak incidence around the 5th decade (50 years). **Clinical Pearls for NEET-PG:** * **Spread:** FTC spreads primarily via the **hematogenous route** (blood), most commonly to the lungs and bones (osteolytic lesions). PTC spreads via lymphatics. * **Hürthle Cell Carcinoma:** A variant of FTC characterized by oxyphilic cells; it is more likely to spread to lymph nodes than typical FTC. * **Treatment:** Total thyroidectomy followed by Radioactive Iodine (RAI) ablation is the standard for tumors >1 cm. * **Marker:** Serum **Thyroglobulin** is used as a tumor marker for post-operative surveillance.

Q: Which of the following is a key step in the surgical management of a thyroglossal cyst?

Excision of the central portion of the hyoid bone. The surgical management of a thyroglossal cyst is defined by the **Sistrunk Procedure**. This procedure is based on the embryological development of the thyroid gland, which descends from the foramen caecum at the base of the tongue to its final position in the neck. ### Why Option A is Correct The thyroglossal duct has an intimate relationship with the **hyoid bone**, often passing anterior, posterior, or even through it. To ensure complete removal and prevent recurrence, the **central portion of the hyoid bone** must be excised along with the cyst and the entire ductal tract up to the foramen caecum. Failure to remove the hyoid bone is the most common cause of recurrence. ### Why Other Options are Incorrect * **Option B & D:** While strap muscles (including the sternothyroid) are retracted or divided to gain access to the cyst, their dissection is a surgical approach step, not the "key" curative step of the procedure. * **Option C:** Isthmusectomy and subtotal thyroidectomy are used for thyroid pathologies (like multinodular goiter or certain malignancies). They are not indicated for a thyroglossal cyst unless there is a rare associated thyroid malignancy. ### High-Yield Clinical Pearls for NEET-PG * **Most common location:** Subhyoid (65%). * **Clinical Sign:** The cyst moves upward on **protrusion of the tongue** (due to its attachment to the foramen caecum) and on deglutition. * **Diagnosis:** Ultrasound is the initial investigation to confirm the cyst and ensure a normal thyroid gland is present elsewhere. * **Recurrence Rate:** Reduced from ~50% to <5% by performing the Sistrunk Procedure. * **Malignancy:** Most common cancer in a thyroglossal cyst is **Papillary Carcinoma of the Thyroid**.

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

Multiple Endocrine Neoplasia (MEN) 2B syndrome. **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.

Q: 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?

Iodine 131 ablation. **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.

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

Surgery only. **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 1

In pheochromocytoma, which of the following is NOT part of the 'rule of 10'?

Accepted Answer

10% are symptomatic

Answer

10% are bilateral

Answer

10% are malignant

Answer

10% are extra-adrenal

Question 2

Thyroid storm after operation is typically due to which of the following factors?

Accepted Answer

Inadequate control of preoperative hyperthyroidism

Answer

Massive intraoperative bleeding

Answer

Recurrent laryngeal nerve injury

Answer

Postoperative infection

Question 3

In which of the following thyroid malignancies does the size of the primary lesion have a greater impact on prognosis than lymph node metastasis?

Accepted Answer

Papillary carcinoma

Answer

Follicular carcinoma

Answer

Medullary carcinoma

Answer

Anaplastic carcinoma

Question 4

A 29-year-old woman underwent a thyroidectomy. Postoperatively, the patient presented with hoarseness. Which of the following nerves was most likely injured during the operation?

Accepted Answer

Recurrent laryngeal

Answer

Internal laryngeal

Answer

External laryngeal

Answer

Superior laryngeal

Question 5

Which of the following is FALSE regarding follicular thyroid cancer?

Accepted Answer

It is not encapsulated.

Answer

It is more common in endemic areas and is more malignant in females.

Answer

Fine needle aspiration cytology (FNAC) cannot reliably differentiate follicular adenoma from follicular carcinoma.

Answer

It is common at 50 years of age.

Question 6

Which of the following is a key step in the surgical management of a thyroglossal cyst?

Accepted Answer

Excision of the central portion of the hyoid bone

Answer

Dissection of the sternothyroid muscle

Answer

Isthmusectomy with subtotal thyroidectomy

Answer

Dissection of the strap muscles of the neck

Question 7

Prophylactic thyroidectomy is indicated for which of the following conditions?

Accepted Answer

Multiple Endocrine Neoplasia (MEN) 2B syndrome

Answer

Hashimoto's thyroiditis

Answer

Riedel's thyroiditis

Answer

Graves' disease

Question 8

What is the treatment for parathyroid adenoma?

Accepted Answer

Removal of the adenoma

Answer

Calcitonin and steroid

Answer

Total parathyroidectomy and implantation in the arm

Answer

Total parathyroidectomy

Question 9

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?

Accepted Answer

Iodine 131 ablation

Answer

External irradiation to the neck

Answer

Thyroxine therapy

Answer

Modified radical neck dissection

Question 10

What is the primary treatment for Medullary Carcinoma of the thyroid?

Accepted Answer

Surgery only

Answer

Surgery and radiotherapy

Answer

Radiotherapy and chemotherapy

Answer

Radioiodine ablation

Endocrine Surgery — MCQs

Endocrine Surgery — MCQs

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