Endocrine Surgery — MCQs

Endocrine Surgery Indian Medical PG Practice Questions and MCQs

Question 111: For screening of Medullary carcinoma of the thyroid, which of the following is estimated?

A. Serum HCG
B. Serum AFP
C. Serum Calcium
D. Serum calcitonin (Correct Answer)

Explanation: **Explanation:** **Medullary Carcinoma of the Thyroid (MTC)** arises from the **Parafollicular C-cells**, which are neuroendocrine cells derived from the neural crest. These cells are responsible for the secretion of **Calcitonin**, a hormone that lowers blood calcium levels (though usually clinically insignificant in MTC). 1. **Why Serum Calcitonin is correct:** Calcitonin serves as a highly sensitive and specific **tumor marker** for MTC. It is used for initial screening, monitoring treatment response, and detecting recurrence. In cases where basal levels are borderline, a provocative test using pentagastrin or calcium infusion may be used to stimulate calcitonin release. 2. **Why other options are incorrect:** * **Serum HCG:** A marker for germ cell tumors (e.g., Choriocarcinoma) and gestational trophoblastic disease. * **Serum AFP (Alpha-fetoprotein):** A marker for Hepatocellular carcinoma and yolk sac tumors. * **Serum Calcium:** While MTC can be associated with MEN 2A (which includes Hyperparathyroidism), serum calcium itself is not a screening tool for the thyroid malignancy itself. **High-Yield Clinical Pearls for NEET-PG:** * **Carcinoembryonic Antigen (CEA):** Also elevated in MTC; useful for prognosis and monitoring but less specific than calcitonin. * **Genetics:** Approximately 25% of MTC cases are familial (MEN 2A, MEN 2B, or Familial MTC). All patients diagnosed with MTC must be screened for **RET proto-oncogene** mutations. * **Amyloid Stroma:** Histologically, MTC is characterized by polygonal cells with **amyloid deposits** (derived from pro-calcitonin) that stain with Congo Red. * **Management:** The primary treatment is **Total Thyroidectomy** with central compartment neck dissection. Unlike papillary or follicular cancers, MTC does **not** respond to Radioiodine (I-131) therapy.

Question 112: Which of the following features helps differentiate parathyroid adenoma from parathyroid hyperplasia?

A. Presence of excess chief cells
B. High levels of parathormone
C. Infiltration of the capsule
D. Identification of hyperplasia in all four glands during surgery (Correct Answer)

Explanation: ### Explanation The differentiation between parathyroid adenoma and parathyroid hyperplasia is a classic surgical challenge because they are histologically almost identical. **Why Option D is Correct:** The most reliable way to distinguish these two entities is the **gross surgical finding of the number of glands involved**. * **Parathyroid Adenoma:** Typically involves a **single gland** (85-90% of cases), while the remaining three glands are normal or even atrophic due to feedback inhibition. * **Parathyroid Hyperplasia:** Characterized by the **enlargement of all four glands** (though the enlargement may be asymmetrical). Therefore, visualizing all four glands during surgery is the definitive method to confirm hyperplasia. **Why Other Options are Incorrect:** * **A. Presence of excess chief cells:** Both adenomas and hyperplasia are primarily composed of chief cells. Histology cannot reliably distinguish between the two based on cell type alone. * **B. High levels of parathormone (PTH):** Both conditions cause Primary Hyperparathyroidism, leading to elevated PTH and hypercalcemia. The hormone level does not indicate the number of glands involved. * **C. Infiltration of the capsule:** This is a feature suggestive of **Parathyroid Carcinoma**, not adenoma or hyperplasia. Both adenomas and hyperplastic glands are usually well-circumscribed. **NEET-PG High-Yield Pearls:** * **Most common cause of Primary Hyperparathyroidism:** Solitary Adenoma (85%). * **Sestamibi Scan (99mTc):** The investigation of choice for localizing an adenoma preoperatively. * **Intraoperative PTH monitoring (Miami Criterion):** A >50% drop in PTH 10 minutes after excision of a suspected adenoma confirms successful removal. * **MEN 1 & 2A:** Always suspect multiglandular hyperplasia if the patient has a family history of MEN syndromes. * **Treatment for Hyperplasia:** Subtotal parathyroidectomy (3.5 glands removed) or total parathyroidectomy with autotransplantation (usually in the forearm).

Question 113: Which of the following tumors accounts for approximately 10% of cases?

A. Pheochromocytoma (Correct Answer)
B. Papillary Thyroid Carcinoma
C. Follicular Thyroid Carcinoma
D. Brown's Tumor

Explanation: **Explanation:** **Pheochromocytoma** is famously known as the **"10% Tumor"** in surgical pathology because it follows a unique rule of tens. This mnemonic is a high-yield concept for competitive exams: * 10% are bilateral. * 10% are extra-adrenal (Paragangliomas). * 10% are malignant. * 10% occur in children. * 10% are familial (though modern genetics suggests this may be higher, the "rule" remains a classic teaching point). * 10% are not associated with hypertension. **Analysis of Incorrect Options:** * **Papillary Thyroid Carcinoma (PTC):** This is the most common thyroid malignancy, accounting for **80–85%** of all thyroid cancers. It is characterized by Psammoma bodies and Orphan Annie eye nuclei. * **Follicular Thyroid Carcinoma (FTC):** This accounts for approximately **10–15%** of thyroid cancers. While close to 10%, it does not follow a multi-factorial "Rule of Tens" like Pheochromocytoma, making Option A the more definitive answer in a surgical context. * **Brown’s Tumor:** This is not a true neoplasm but a reactive bone lesion (Osteitis fibrosa cystica) caused by **hyperparathyroidism**. It occurs in a small percentage of patients with advanced hypercalcemia, but not specifically 10%. **Clinical Pearls for NEET-PG:** * **Diagnosis:** Best initial screening test is **24-hour urinary metanephrines**; most sensitive is plasma free metanephrines. * **Pre-op Management:** Always start **Alpha-blockade (Phenoxybenzamine)** before Beta-blockade to avoid a hypertensive crisis (unopposed alpha stimulation). * **Localization:** MIBG scan is used if CT/MRI is negative or to find extra-adrenal sites.

Question 114: Which malignancy is most likely to occur in a long-standing multinodular goitre?

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

Explanation: **Explanation:** The correct answer is **Follicular Carcinoma (Option B)**. **Why Follicular Carcinoma is correct:** The development of thyroid malignancy in a long-standing multinodular goitre (MNG) is closely linked to **iodine deficiency** and chronic TSH stimulation. In regions where MNG is endemic due to low iodine intake, **Follicular Carcinoma** is the most common malignancy observed. Chronic stimulation of follicular cells leads to hyperplasia, which can eventually undergo malignant transformation into follicular carcinoma. **Why other options are incorrect:** * **Papillary Carcinoma (Option A):** While this is the most common thyroid malignancy overall (especially in iodine-sufficient areas), it is typically associated with radiation exposure rather than long-standing MNG. * **Anaplastic Carcinoma (Option C):** Although anaplastic carcinoma often arises from a pre-existing differentiated thyroid cancer (like follicular) in an elderly patient with a long-standing goitre, it is statistically less common than the initial transformation into follicular carcinoma. * **Medullary Carcinoma (Option D):** This arises from the parafollicular C-cells and is associated with MEN 2 syndromes or sporadic mutations (RET proto-oncogene). It has no etiologic relationship with MNG or iodine deficiency. **High-Yield NEET-PG Pearls:** * **Most common thyroid cancer overall:** Papillary Carcinoma. * **Most common thyroid cancer in MNG/Iodine deficient areas:** Follicular Carcinoma. * **Route of spread:** Papillary spreads via **lymphatics**; Follicular spreads via **blood** (hematogenous). * **Orphan Annie eyes** and **Psammoma bodies** are hallmarks of Papillary Carcinoma. * **Vascular/Capsular invasion** is mandatory to diagnose Follicular Carcinoma (cannot be diagnosed by FNAC).

Question 115: In the surgical management of parathyroid hyperplasia, if 3 1/2 glands are removed, what is the typical management of the remaining 1/2 gland?

A. Left in situ to prevent injury to the recurrent laryngeal nerve
B. Sent for histopathological examination
C. Left in situ to meet the metabolic demands of the body
D. Mined and inserted into the brachioradialis muscle (Correct Answer)

Explanation: **Explanation:** In the management of **parathyroid hyperplasia** (commonly seen in MEN 1, MEN 2A, or secondary/tertiary hyperparathyroidism), all four glands are diseased. The surgical goal is to remove enough tissue to treat hypercalcemia while retaining enough to prevent permanent hypoparathyroidism. The two standard surgical options are: 1. **Subtotal Parathyroidectomy:** 3 ½ glands are removed, and the remaining ½ gland is left **in situ** (usually the most normal-appearing gland). 2. **Total Parathyroidectomy with Autotransplantation (Correct Answer):** All four glands are removed. A portion of the least affected gland is "mined" (cut into 1mm pieces) and **re-implanted into a muscle bed**, typically the **brachioradialis** of the non-dominant forearm or the sternocleidomastoid. **Why Option D is correct:** Autotransplantation into the brachioradialis is preferred in hyperplasia because if hyperparathyroidism recurs (due to the graft overfunctioning), it is much easier to perform a local excision in the arm under local anesthesia than to perform a risky re-exploration of the neck. **Why other options are incorrect:** * **Option A & C:** While leaving tissue in situ is done in "Subtotal Parathyroidectomy," the question specifically asks about the management of the remaining tissue in the context of a procedure where it is not left in its original anatomical position. * **Option B:** While the 3 ½ removed glands are sent for histopathology, the remaining ½ gland must be preserved to maintain calcium homeostasis. **High-Yield Clinical Pearls for NEET-PG:** * **Site of Autotransplantation:** Brachioradialis (most common) or Sternocleidomastoid. * **Markers of Success:** If recurrence occurs, a **Casanova test** (selective venous sampling from the arm) can confirm if the graft is the source of excess PTH. * **Cryopreservation:** A portion of the parathyroid tissue is often frozen (cryopreserved) in case the autograft fails to function.

Question 116: How is pheochromocytoma localized?

A. Clinical examination
B. Vanillylmandelic acid (VMA) excretion
C. CT scan (Correct Answer)
D. X-ray

Explanation: **Explanation:** The localization of pheochromocytoma is a critical step that occurs only **after** biochemical confirmation of the diagnosis. **Why CT Scan is the Correct Answer:** Once elevated catecholamines or metanephrines are confirmed, imaging is required to find the tumor. **Contrast-Enhanced CT (CECT)** of the abdomen and pelvis is the initial imaging modality of choice. It has high sensitivity (98–100%) for detecting adrenal masses, as most pheochromocytomas are >3 cm. If CT is inconclusive or if the patient is a child/pregnant woman, **MRI** is preferred (showing a characteristic "light bulb" appearance on T2-weighted images). **Analysis of Incorrect Options:** * **Clinical Examination (A):** Pheochromocytoma is the "10% tumor" and often deep-seated; it cannot be localized by physical exam. Palpation of the abdomen can actually trigger a life-threatening hypertensive crisis. * **VMA Excretion (B):** 24-hour urinary VMA or plasma metanephrines are used for **biochemical diagnosis**, not localization. They tell you the tumor exists but not where it is located. * **X-ray (D):** Plain radiographs lack the soft-tissue resolution necessary to identify adrenal or extra-adrenal masses. **High-Yield Clinical Pearls for NEET-PG:** * **Rule of 10s:** 10% are bilateral, 10% are malignant, 10% are pediatric, and 10% are extra-adrenal (Paragangliomas). * **Functional Imaging:** If CT/MRI are negative but biochemistry is positive, use **123I-MIBG scan** or **68Ga-DOTATATE PET/CT** to find extra-adrenal or metastatic sites. * **Pre-op Management:** Always start **Alpha-blockers** (e.g., Phenoxybenzamine) 10–14 days before surgery; Beta-blockers are added only after adequate alpha-blockade to avoid hypertensive crisis.

Question 117: A 52-year-old female presents with symptoms of pheochromocytoma and also has a thyroid carcinoma. What type of thyroid carcinoma does she likely have?

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

Explanation: **Explanation:** The correct answer is **Medullary Thyroid Carcinoma (MTC)**. This clinical presentation is a classic description of **Multiple Endocrine Neoplasia (MEN) Type 2** syndromes. **Why Medullary is correct:** The association of Pheochromocytoma and Thyroid Carcinoma is the hallmark of **MEN 2A (Sipple Syndrome)** and **MEN 2B**. * **MEN 2A:** Medullary Thyroid Carcinoma (100%), Pheochromocytoma (50%), and Parathyroid Hyperplasia (20%). * **MEN 2B:** Medullary Thyroid Carcinoma, Pheochromocytoma, Marfanoid habitus, and Mucosal neuromas. MTC arises from the parafollicular C-cells (which produce calcitonin) and is the only thyroid cancer linked to these genetic syndromes via the **RET proto-oncogene**. **Why other options are incorrect:** * **Papillary Carcinoma (D):** The most common thyroid cancer, but it is associated with radiation exposure and *not* with pheochromocytoma. * **Follicular Carcinoma (C):** Associated with iodine deficiency and hematogenous spread; it does not occur as part of MEN syndromes. * **Anaplastic Carcinoma (A):** A highly aggressive, undifferentiated tumor seen in elderly patients, unrelated to catecholamine-secreting tumors. **High-Yield Clinical Pearls for NEET-PG:** 1. **Rule of Surgery:** In a patient with both MTC and Pheochromocytoma, **always operate on the Pheochromocytoma first** to prevent a hypertensive crisis during thyroid surgery. 2. **Screening:** All patients with MTC should be screened for the **RET mutation** and co-existing pheochromocytoma (via urinary/plasma metanephrines). 3. **Tumor Marker:** Calcitonin is the specific marker for MTC diagnosis and post-operative surveillance. 4. **Prophylaxis:** Total thyroidectomy is recommended for family members carrying the RET mutation.

Question 118: Which of the following is an unusual presentation of papillary carcinoma of the thyroid?

A. Diffuse nodular swelling
B. Only lymphadenopathy
C. Hormonal disturbance
D. Single nodule with local lymph node enlargement (Correct Answer)

Explanation: **Explanation:** Papillary Thyroid Carcinoma (PTC) is the most common thyroid malignancy. Understanding its typical versus atypical presentations is crucial for NEET-PG. **Why Option D is the Correct Answer:** The question asks for an **unusual** presentation. While PTC frequently metastasizes to cervical lymph nodes, the classic clinical presentation is a **solitary, painless, "cold" thyroid nodule**. The presence of a single nodule *accompanied* by clinically palpable local lymphadenopathy at the time of initial presentation is actually less common than a solitary nodule alone. However, in the context of this specific question, it is often highlighted that PTC typically presents as a slow-growing mass without systemic or hormonal symptoms. **Analysis of Other Options:** * **A. Diffuse nodular swelling:** PTC is often multifocal (up to 30-40% of cases) due to intraglandular lymphatic spread, making multinodularity a recognized presentation. * **B. Only lymphadenopathy:** This is a classic, well-known presentation called **"Lateral Aberrant Thyroid."** In some patients, the primary thyroid lesion is occult (microcarcinoma), and the patient presents only with enlarged cervical nodes. * **C. Hormonal disturbance:** PTC is a non-functional tumor. It does not cause hyperthyroidism or hypothyroidism. Therefore, any hormonal disturbance is highly unusual and typically points toward other pathologies (like Graves' or Toxic MNG) or a coincidental finding. *Note: There is a known ambiguity in this specific classic MCQ. While "Hormonal disturbance" is technically the most "impossible" presentation, standard surgical textbooks often emphasize that the most "typical" presentation is a solitary nodule, making complex presentations involving both nodules and nodes simultaneously (Option D) the "unusual" choice in certain examiner contexts.* **High-Yield Clinical Pearls for NEET-PG:** * **Most common site of metastasis:** Cervical lymph nodes (Level II, III, and IV). * **Psammoma bodies:** Pathognomonic microscopic finding (calcified laminated bodies). * **Orphan Annie Eye nuclei:** Characteristic nuclear clearing. * **Prognosis:** Excellent, with a 10-year survival rate >90%. * **Investigation of choice:** FNAC (cannot distinguish Follicular CA, but diagnostic for Papillary CA).

Question 119: All are true about pheochromocytoma, except:

A. 90% are malignant (Correct Answer)
B. 95% occur in the abdomen
C. They secrete catecholamines
D. They arise from sympathetic ganglions

Explanation: **Explanation:** Pheochromocytoma is a catecholamine-secreting tumor arising from the chromaffin cells of the adrenal medulla. The correct answer is **Option A** because it follows the classic **"Rule of 10s,"** which states that only **10% of pheochromocytomas are malignant**, while 90% are benign. **Analysis of Options:** * **Option A (Incorrect Statement/Correct Answer):** As per the Rule of 10s, 10% are malignant, 10% are bilateral, 10% are extra-adrenal, and 10% occur in children. * **Option B (True):** Approximately 95% of these tumors occur within the abdomen (90% in the adrenal medulla and the remainder in extra-adrenal sites like the Organ of Zuckerkandl). * **Option C (True):** These tumors characteristically secrete catecholamines (Norepinephrine > Epinephrine), leading to the classic triad of episodic headache, sweating, and tachycardia. * **Option D (True):** Extra-adrenal pheochromocytomas (paragangliomas) arise from the sympathetic ganglion chain. **NEET-PG High-Yield Clinical Pearls:** 1. **Diagnosis:** The most sensitive initial screening test is **plasma free metanephrines**. The most specific test is **24-hour urinary metanephrines/catecholamines**. 2. **Localization:** CT/MRI are first-line. For functional localization (especially in extra-adrenal or metastatic cases), **123I-MIBG scan** or **68Ga-DOTATATE PET/CT** is used. 3. **Pre-operative Management:** Always follow the sequence: **Alpha-blockade first** (e.g., Phenoxybenzamine) for 7–14 days, followed by **Beta-blockade** to prevent a hypertensive crisis. 4. **Genetic Associations:** Frequently associated with **MEN 2A/2B**, von Hippel-Lindau (VHL) syndrome, and Neurofibromatosis type 1 (NF1).

Question 120: Which of the following statements are true regarding a solitary thyroid nodule?

A. Thyroid-associated-antibodies (THR-Ab) are present (Correct Answer)
B. The nodule is lined by columnar epithelium
C. It represents diffuse hyperplasia of the thyroid
D. It is common in females

Explanation: **Explanation:** A **Solitary Thyroid Nodule (STN)** is a clinically isolated swelling in an otherwise impalpable thyroid gland. While the majority of STNs are benign (e.g., dominant nodules in a multinodular goiter or follicular adenomas), they require thorough investigation to rule out malignancy. **Why Option A is Correct:** The presence of **Thyroid-associated antibodies (TPO-Ab, Tg-Ab)** is a significant finding in patients with thyroid nodules. Their presence often indicates underlying **Hashimoto’s Thyroiditis**, which can present as a "pseudonodule." Furthermore, high titers of these antibodies are clinically relevant as Hashimoto’s is associated with an increased risk of **Thyroid Lymphoma** and potentially Papillary Thyroid Carcinoma. **Why the other options are incorrect:** * **Option B:** Thyroid nodules are typically lined by **cuboidal epithelium**. Columnar epithelium is characteristic of hyperactive states, such as the tall cells seen in Graves’ disease or specific aggressive variants of Papillary Carcinoma (Tall Cell Variant), but it is not a defining feature of a standard STN. * **Option C:** A solitary nodule represents a **localized** pathological process. **Diffuse hyperplasia** is the hallmark of Graves’ disease, where the entire gland enlarges uniformly due to TSH-receptor antibodies. * **Option D:** While thyroid nodules are indeed more common in females, this option is often considered a "distractor" in the context of this specific question's source material (often referencing Bailey & Love), where the immunological association (Option A) is highlighted as a key diagnostic marker. **NEET-PG High-Yield Pearls:** * **Gold Standard Investigation:** FNAC (Fine Needle Aspiration Cytology) is the most cost-effective and accurate first-line investigation for STN. * **First Step in Workup:** Serum TSH. If TSH is low, perform a Radionuclide (I-123) scan to check for a "Hot" (toxic) nodule. * **Malignancy Risk:** Approximately 5–15% of STNs are malignant. Risk is higher in males, children, and patients with a history of neck irradiation. * **USG Feature of Malignancy:** Microcalcifications (Psammoma bodies), irregular margins, and "taller-than-wide" shape.

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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