Endocrine Surgery — MCQs

A 42-year-old woman presents with a diffuse swelling in front of her neck. Thyroid function tests are within normal limits. A fine-needle biopsy reveals malignant cells. On examination of the excised tumor, the tumor cells are positive for calcitonin on immunohistochemistry. What is the appropriate pathologic diagnosis?

Endocrine Surgery Indian Medical PG Practice Questions and MCQs

Question 61: What is the most common cause of respiratory distress after thyroidectomy?

A. Bilateral recurrent laryngeal nerve palsy
B. Cervical hematoma
C. Laryngeal edema (Correct Answer)
D. Hyperparathyroidism

Explanation: **Explanation:** Respiratory distress following thyroidectomy is a critical surgical emergency. While multiple factors can contribute, **laryngeal edema** is statistically the **most common cause** of post-operative airway obstruction. **1. Why Laryngeal Edema is Correct:** Laryngeal edema typically results from trauma during endotracheal intubation, surgical manipulation of the trachea, or venous/lymphatic congestion following the removal of a large goiter. It leads to narrowing of the glottic aperture, causing inspiratory stridor and respiratory distress, usually manifesting within the first few hours post-surgery. **2. Analysis of Incorrect Options:** * **Bilateral Recurrent Laryngeal Nerve (RLN) Palsy:** This is the **most serious** cause of immediate airway obstruction (due to the vocal cords remaining in the paramedian position), but it is rare compared to edema. * **Cervical Hematoma:** This is the most common cause of **tension-related** airway distress. It causes venous congestion and secondary laryngeal edema rather than direct tracheal compression. It is a surgical emergency requiring immediate bedside evacuation. * **Hypoparathyroidism:** (Note: Option D says Hyperparathyroidism, which is incorrect). Hypocalcemia resulting from hypoparathyroidism can cause **laryngospasm** (Tetany), but this typically occurs 24–72 hours post-operatively, not immediately. **Clinical Pearls for NEET-PG:** * **Most common cause overall:** Laryngeal edema. * **Most common cause of "Tension" distress:** Reactionary hemorrhage (Hematoma). * **Management of Hematoma:** Immediate opening of the wound at the bedside (do not wait for the OR). * **Tracheomalacia:** Consider this if the patient has had a long-standing, large goiter causing pressure atrophy of tracheal rings. * **Unilateral RLN injury:** Presents as hoarseness, not respiratory distress.

Question 62: What is the prognosis associated with Multiple Endocrine Neoplasia type 2 (MEN 2) syndromes?

A. Good prognosis
B. Bad prognosis (Correct Answer)
C. Late presentation
D. Chromosome 11 mutation

Explanation: **Explanation:** The prognosis of **Multiple Endocrine Neoplasia type 2 (MEN 2)** is generally considered **bad** (poor) primarily due to the aggressive nature of **Medullary Thyroid Carcinoma (MTC)**, which is present in nearly 100% of affected individuals. Unlike the more common papillary thyroid cancers, MTC does not respond to radioactive iodine or hormone suppression, and it tends to metastasize early to cervical and mediastinal lymph nodes. Within the MEN 2 spectrum, **MEN 2B** carries the worst prognosis because MTC develops in early childhood and is highly virulent. **Analysis of Options:** * **A. Good prognosis:** Incorrect. The high mortality rate associated with early-onset MTC and the potential for hypertensive crises from associated Pheochromocytomas make the overall prognosis poor compared to MEN 1. * **C. Late presentation:** Incorrect. MEN 2 syndromes often present **early** (especially MEN 2B in infancy/childhood). Current clinical guidelines mandate early screening and prophylactic thyroidectomy based on genetic testing. * **D. Chromosome 11 mutation:** Incorrect. MEN 2 is caused by a mutation in the **RET proto-oncogene on Chromosome 10**. Chromosome 11 (MEN1 gene) is associated with MEN type 1 (Wermer’s Syndrome). **High-Yield Clinical Pearls for NEET-PG:** * **Genetic Basis:** MEN 2 is autosomal dominant; caused by a gain-of-function mutation in the **RET proto-oncogene**. * **MEN 2A (Sipple Syndrome):** MTC + Pheochromocytoma + Parathyroid Hyperplasia. * **MEN 2B (Wagenmann-Froboese):** MTC + Pheochromocytoma + Mucosal Neuromas + Marfanoid habitus (No parathyroid involvement). * **Management:** Prophylactic thyroidectomy is the treatment of choice, often performed before age 5 (MEN 2A) or even in infancy (MEN 2B). Always exclude/treat Pheochromocytoma before any surgery to prevent intraoperative hypertensive crisis.

Question 63: Minimally invasive video-assisted thyroidectomy can be performed in all of the following conditions EXCEPT:

A. Benign solitary nodule
B. Thyroid volume <25mL
C. Prior neck surgery (Correct Answer)
D. Follicular neoplasm

Explanation: **Explanation:** Minimally Invasive Video-Assisted Thyroidectomy (MIVAT), popularized by Miccoli, is a technique used to perform thyroid surgery through a small incision (usually 1.5–2 cm) with the aid of an endoscope. **Why "Prior neck surgery" is the correct answer:** Prior neck surgery or neck irradiation is a **strict contraindication** for MIVAT. Previous surgery leads to the formation of dense adhesions and loss of normal anatomical planes. This increases the risk of injury to the recurrent laryngeal nerve and parathyroid glands, making the limited visualization and restricted maneuverability of the video-assisted approach unsafe. **Analysis of Incorrect Options:** * **Benign solitary nodule:** This is the most common indication for MIVAT. As long as the nodule size is within limits (typically <30–35 mm), it is easily managed. * **Thyroid volume <25mL:** Small thyroid volume is a primary selection criterion. Large glands cannot be safely delivered through the small MIVAT incision. * **Follicular neoplasm:** Low-risk malignancies and follicular neoplasms (where the diagnosis of malignancy is uncertain pre-operatively) are suitable for MIVAT, provided the nodule size is small. **NEET-PG High-Yield Pearls:** * **Incision size:** 1.5 to 2 cm (compared to 6-8 cm in conventional surgery). * **Inclusion Criteria:** Nodule diameter ≤ 35 mm, total thyroid volume < 20-25 mL, and no evidence of thyroiditis or lymphadenopathy. * **Contraindications:** Large goiters, previous neck surgery/radiation, locally invasive malignancy, and Hashimoto’s thyroiditis (due to increased vascularity and friability). * **Advantage:** Better cosmetic outcome and reduced postoperative pain.

Question 64: All of the following are true about insulinoma EXCEPT:

A. It is usually asymptomatic and requires no treatment. (Correct Answer)
B. It is usually small and multiple.
C. Diazoxide and octreotide reduce insulin synthesis.
D. The most common site is the pancreas.

Explanation: **Explanation:** Insulinoma is the most common functional neuroendocrine tumor (NET) of the pancreas. The correct answer is **Option A** because insulinomas are **never asymptomatic**; they characteristically present with **Whipple’s Triad**: symptoms of hypoglycemia (confusion, sweating, palpitations), documented low blood glucose (<50 mg/dL), and immediate relief of symptoms upon glucose administration. Treatment is mandatory, usually via surgical resection (enucleation), as the hypoglycemia can be life-threatening. **Analysis of other options:** * **Option B:** While 90% of insulinomas are solitary and benign, they are typically **small** (<2 cm). In the context of MEN-1 syndrome, they are frequently **multiple**, making this a characteristic feature to consider during surgical mapping. * **Option C:** Medical management is used for preoperative stabilization or in inoperable cases. **Diazoxide** inhibits insulin release from beta cells, and **Octreotide** (a somatostatin analogue) suppresses insulin secretion by binding to SSTR receptors. * **Option D:** The **pancreas** is the primary site; insulinomas are distributed equally across the head, body, and tail of the pancreas. **High-Yield Clinical Pearls for NEET-PG:** * **Rule of 90s:** 90% are solitary, 90% are benign, 90% are <2 cm, and 90% are intrapancreatic. * **Diagnosis:** The gold standard is the **72-hour supervised fast** (showing elevated insulin and C-peptide levels despite hypoglycemia). * **Localization:** Intraoperative ultrasound (IOUS) is the most sensitive method for localization during surgery. * **Association:** If multiple, suspect **MEN-1 syndrome**.

Question 65: Which nerve is most likely to be involved in malignant spread and thyroid surgery?

A. Recurrent laryngeal nerve
B. Superior laryngeal nerve
C. Internal laryngeal nerve
D. Both recurrent laryngeal nerve and superior laryngeal nerve (Correct Answer)

Explanation: **Explanation:** In thyroid surgery and the progression of thyroid malignancies, both the **Recurrent Laryngeal Nerve (RLN)** and the **Superior Laryngeal Nerve (SLN)** are at significant risk, albeit for different anatomical reasons. 1. **Recurrent Laryngeal Nerve (RLN):** This is the nerve most commonly associated with thyroid surgery. It lies in the tracheoesophageal groove, in close proximity to the posterior aspect of the thyroid gland and the inferior thyroid artery. Malignant tumors (especially those with extrathyroidal extension) frequently invade this nerve, leading to vocal cord paralysis. 2. **Superior Laryngeal Nerve (SLN):** Specifically, the **external branch** of the SLN is at high risk during the ligation of the superior thyroid vascular pedicle. It runs close to the superior pole of the thyroid. While less commonly "invaded" by malignancy than the RLN, it is frequently "involved" in surgical dissection and can be compromised by large superior pole tumors. **Why Option D is correct:** Standard surgical teaching and NEET-PG patterns emphasize that both nerves are vulnerable. While the RLN is more famous for causing hoarseness, injury to the external branch of the SLN leads to loss of pitch (the "monotone voice"), which is equally critical for professional speakers. **Analysis of Incorrect Options:** * **Options A & B:** These are partially correct but incomplete. In the context of "malignant spread and surgery," both nerves constitute the primary neurological risks. * **Option C:** The Internal Laryngeal Nerve is purely sensory to the larynx above the vocal cords and is generally well-protected within the thyrohyoid membrane, making it less likely to be involved compared to the motor branches. **High-Yield Clinical Pearls for NEET-PG:** * **Most common nerve injured in thyroidectomy:** External branch of the Superior Laryngeal Nerve (often under-diagnosed). * **Nerve of Amelita Galli-Curci:** External branch of SLN (injury causes inability to hit high notes). * **Berry’s Ligament:** The most common site of RLN injury during surgery. * **Bilateral RLN injury:** Results in acute airway obstruction (emergency tracheostomy may be needed).

Question 66: All of the following regarding papillary carcinoma of the thyroid is true EXCEPT:

A. Multicentric origin
B. Secondaries to lymph nodes
C. Slow growing
D. Bony metastasis in early stage (Correct Answer)

Explanation: **Explanation:** Papillary Thyroid Carcinoma (PTC) is the most common thyroid malignancy (80-85%). The correct answer is **D** because PTC is characterized by **lymphatic spread** rather than hematogenous spread. Bony metastases are rare and typically occur only in very advanced stages or in the follicular variant. **Why Option D is the correct answer (False statement):** Early bony metastasis is a hallmark of **Follicular Thyroid Carcinoma (FTC)**, which spreads via the bloodstream (hematogenous). In contrast, PTC spreads primarily via lymphatics to the cervical lymph nodes. **Why other options are incorrect (True statements):** * **A. Multicentric origin:** PTC is frequently multifocal (up to 60-80% of cases), involving both lobes due to intraglandular lymphatic spread. * **B. Secondaries to lymph nodes:** This is the most common mode of spread. Approximately 50% of patients have cervical lymph node involvement at the time of diagnosis. * **C. Slow growing:** PTC is an indolent tumor with an excellent prognosis; the 10-year survival rate often exceeds 90%. **NEET-PG High-Yield Pearls:** * **Pathology:** Look for **Psammoma bodies** (calcified laminations) and **Orphan Annie eye nuclei** (clear nuclei with central clearing). * **Risk Factor:** Prior exposure to **ionizing radiation** is the most significant risk factor. * **Diagnosis:** FNAC is the investigation of choice (cannot distinguish between Follicular Adenoma and Carcinoma, but is definitive for Papillary). * **Prognosis:** Excellent, often staged using the **AMES** or **MACIS** criteria.

Question 67: A patient is diagnosed with a prolactinoma encircling the carotid artery. What is the best line of management?

A. Wait and watch
B. Transsphenoidal surgical resection (Correct Answer)
C. Radiotherapy
D. Combination therapy

Explanation: **Explanation:** The management of prolactinomas typically follows a medical-first approach. However, the presence of **vascular encasement** or significant local invasion (like encircling the carotid artery) often necessitates surgical intervention, especially if there is a risk of neurological deficit or if the tumor is refractory to medical therapy. **1. Why Transsphenoidal Surgical Resection is Correct:** While dopamine agonists (Cabergoline/Bromocriptine) are the first-line treatment for most prolactinomas, **Transsphenoidal Surgery (TSS)** is indicated when the tumor causes significant mass effect, involves critical structures like the carotid artery, or shows resistance to medical management. In the context of surgical exams, a tumor "encircling" or "compressing" vital structures often points toward the need for surgical decompression to prevent permanent neurovascular damage. **2. Why Other Options are Incorrect:** * **Wait and Watch:** Prolactinomas are active tumors. Encirclement of the carotid artery indicates an aggressive or large macroadenoma; observation would lead to progressive vision loss or vascular compromise. * **Radiotherapy:** This is reserved as a third-line treatment for residual or recurrent tumors after failed surgery and medical therapy due to its slow onset of action and risk of hypopituitarism. * **Combination Therapy:** While often used in practice (Surgery + Meds), the "best line of management" for a tumor causing structural encasement in a surgical MCQ context is the definitive removal of the mass (TSS). **High-Yield Clinical Pearls for NEET-PG:** * **First-line for Prolactinoma:** Medical management (Cabergoline is preferred over Bromocriptine). * **Indications for Surgery:** CSF rhinorrhea, visual field defects (Bitemporal hemianopia) worsening despite meds, or pituitary apoplexy. * **Most common approach:** Endoscopic Transnasal Transsphenoidal surgery. * **Hook Effect:** A laboratory phenomenon where extremely high prolactin levels appear falsely low; solved by serum dilution.

Question 68: All of the following are true about medullary carcinoma of thyroid except?

A. It is a tumor arising from C cells derived from the neural crest.
B. It secretes high levels of calcitonin.
C. It is not dependent on TSH.
D. Most cases are sporadic. (Correct Answer)

Explanation: **Explanation:** Medullary Carcinoma of the Thyroid (MTC) is a unique neuroendocrine tumor that differs significantly from follicular-cell-derived thyroid cancers (like papillary or follicular carcinoma). **1. Why Option D is the "Except" (Correct Answer):** The question asks for the statement that is **not** true. Option D states "Most cases are sporadic." In reality, approximately **75-80% of MTC cases are sporadic**, while 20-25% are hereditary (associated with MEN 2A, MEN 2B, or Familial MTC). Since the majority of cases *are* indeed sporadic, this statement is factually correct. However, in many competitive exams, this question is often framed to test the knowledge that MTC has a **stronger genetic association** than other thyroid cancers. *Note: If this is a "single best answer" scenario where all statements are technically true, the question may be flawed or intended to highlight that MTC is the classic example of a hereditary thyroid syndrome.* **2. Analysis of Other Options:** * **Option A:** True. MTC arises from **Parafollicular C-cells**, which are embryologically derived from the **ultimobranchial body (neural crest)**. * **Option B:** True. Calcitonin is the primary biomarker for MTC. It is used for diagnosis, screening, and monitoring recurrence. * **Option C:** True. Because MTC arises from C-cells and not follicular cells, it does **not possess TSH receptors**. Therefore, TSH suppression therapy (levothyroxine) is ineffective in treating MTC. **High-Yield Clinical Pearls for NEET-PG:** * **Genetics:** Strongly associated with **RET proto-oncogene** mutations. Prophylactic thyroidectomy is indicated in carriers. * **Pathology:** Characterized by **Amyloid stroma** (stained with Congo Red, showing apple-green birefringence). * **Spread:** Spreads via both lymphatic and hematogenous routes. * **Surgery:** The treatment of choice is **Total Thyroidectomy with Central Compartment Neck Dissection**, as MTC does not take up radioactive iodine (I-131).

Question 69: A female with a history of recurrent renal stones presented with severe bone pain. Laboratory findings are indicative of primary hyperparathyroidism secondary to parathyroid hyperplasia. What is the recommended treatment?

A. Removal of all four parathyroid glands
B. Calcitonin
C. Removal of all parathyroid glands leaving a 50 mg tissue remnant (Correct Answer)
D. Enlargement of parathyroid glands

Explanation: ### Explanation **Concept:** Primary hyperparathyroidism due to **parathyroid hyperplasia** involves all four parathyroid glands. Unlike a solitary adenoma (where only one gland is removed), hyperplasia requires a surgical approach that addresses all hyperfunctioning tissue while preventing permanent hypocalcemia. **Why Option C is Correct:** The standard surgical treatment for parathyroid hyperplasia is **Subtotal Parathyroidectomy**. This involves the removal of 3.5 glands, leaving approximately **30–50 mg** of the most normal-appearing vascularized tissue (usually the superior gland) in situ. Alternatively, a **Total Parathyroidectomy with Autotransplantation** (placing minced tissue into the brachioradialis or sternocleidomastoid) can be performed. Both methods aim to maintain calcium homeostasis while removing the bulk of the overactive tissue. **Why Other Options are Incorrect:** * **Option A:** Total removal of all four glands without autotransplantation leads to **permanent hypoparathyroidism**, necessitating lifelong calcium and Vitamin D supplementation. * **Option B:** Calcitonin is a medical management tool used for acute hypercalcemia; it does not treat the underlying surgical pathology of hyperplasia. * **Option D:** "Enlargement" is a pathological state, not a treatment modality. **High-Yield Clinical Pearls for NEET-PG:** * **Most common cause of Primary Hyperparathyroidism:** Solitary Adenoma (85%). * **Parathyroid Hyperplasia (15%):** Often associated with **MEN 1 and MEN 2A** syndromes. * **Localization:** Sestamibi scan (99mTc-MIBI) is the investigation of choice for preoperative localization. * **Intraoperative Monitoring:** A **>50% drop in intraoperative PTH** (Miami Criteria) 10 minutes after excision confirms successful removal of the hyperfunctioning tissue. * **Hungry Bone Syndrome:** A common postoperative complication characterized by profound hypocalcemia due to rapid bone remineralization.

Question 70: A 42-year-old woman presents with a diffuse swelling in front of her neck. Thyroid function tests are within normal limits. A fine-needle biopsy reveals malignant cells. On examination of the excised tumor, the tumor cells are positive for calcitonin on immunohistochemistry. What is the appropriate pathologic diagnosis?

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

Explanation: ### Explanation **Correct Answer: C. Medullary Carcinoma** The definitive diagnostic clue in this case is the **immunohistochemical (IHC) positivity for calcitonin**. Medullary Thyroid Carcinoma (MTC) originates from the **Parafollicular C-cells** (derived from the neural crest), which are responsible for secreting calcitonin. Unlike other thyroid cancers, MTC is not derived from follicular cells; therefore, patients are typically euthyroid (normal T3, T4, TSH). **Why other options are incorrect:** * **Papillary Carcinoma (D):** The most common thyroid malignancy. It is characterized by nuclear features (Orphan Annie eyes, Psammoma bodies) and is IHC positive for **Thyroglobulin**, not calcitonin. * **Follicular Carcinoma (B):** Derived from follicular cells and spreads hematogenously. Like papillary carcinoma, it is IHC positive for **Thyroglobulin**. * **Anaplastic Carcinoma (A):** A highly aggressive, undifferentiated tumor usually seen in the elderly. It typically presents as a rapidly enlarging mass with compressive symptoms and lacks specific markers like calcitonin. **High-Yield Clinical Pearls for NEET-PG:** * **Biomarkers:** Calcitonin is used for both diagnosis and monitoring recurrence. Carcinoembryonic Antigen (CEA) is also often elevated. * **Genetics:** Approximately 25% of MTC cases are familial (associated with **MEN 2A and 2B** syndromes) due to **RET proto-oncogene** mutations. 75% are sporadic. * **Pathology:** Characterized by deposits of **Amyloid** (formed by pro-calcitonin) which stains with **Congo Red** (showing apple-green birefringence). * **Surgery:** The treatment of choice is **Total Thyroidectomy with Central Compartment Neck Dissection**, as MTC does not concentrate radioiodine (I-131).

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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