Endocrine Surgery Practice Questions

Q: Which of the following is true regarding medullary carcinoma of the thyroid?

Elevated levels of serum calcitonin. **Explanation:** **Medullary Thyroid Carcinoma (MTC)** arises from the **parafollicular C-cells** of the thyroid, which are neuroendocrine cells derived from the neural crest. These cells are responsible for the secretion of **calcitonin**. Therefore, elevated serum calcitonin is a highly sensitive and specific tumor marker for the diagnosis, screening, and monitoring of recurrence in MTC. **Analysis of Options:** * **Option A (Incorrect):** MTC is strongly associated with mutations in the **RET proto-oncogene**, not the MET oncogene. MET is more commonly associated with papillary renal cell carcinoma. * **Option C (Incorrect):** MTC is a component of **MEN 2A and 2B** syndromes. MEN 1 (Wermer’s Syndrome) typically involves the "3 Ps": Pituitary, Parathyroid, and Pancreatic tumors. * **Option D (Incorrect):** **Papillary Thyroid Carcinoma** is the most common type of thyroid cancer (approx. 80-85%). MTC accounts for only about 5-10% of cases. **High-Yield Clinical Pearls for NEET-PG:** 1. **Amyloid Stroma:** Histologically, MTC is characterized by nests of cells separated by an amyloid stroma (stained by Congo Red). 2. **Genetics:** 75% of cases are sporadic; 25% are familial (MEN 2A, 2B, or Familial MTC). 3. **Prophylactic Surgery:** In patients with known RET mutations, prophylactic total thyroidectomy is recommended. 4. **Carcinoembryonic Antigen (CEA):** This is another important tumor marker used alongside calcitonin for MTC. 5. **Spread:** Unlike papillary cancer (lymphatic), MTC spreads via both lymphatic and hematogenous routes.

Q: Which of the following is the most likely type of thyroid cancer with the best prognosis of all thyroid malignancies?

Papillary cancer of the thyroid. **Explanation:** **1. Why Papillary Thyroid Cancer (PTC) is the correct answer:** Papillary thyroid cancer is the most common type of thyroid malignancy (accounting for approximately 80–85% of cases). It is characterized by an **excellent prognosis**, with a 10-year survival rate exceeding 90–95%. The favorable outcome is due to its slow-growing nature, high responsiveness to radioactive iodine (RAI) therapy [1], and tendency to remain localized or spread only to regional lymph nodes rather than distant organs. **2. Why the other options are incorrect:** * **Anaplastic Thyroid Cancer:** This is the most aggressive thyroid malignancy with the **worst prognosis**. It is rapidly enlarging, often fatal within months, and shows poor response to treatment. * **Follicular Thyroid Cancer:** While it has a good prognosis, it is generally considered more aggressive than PTC because it tends to spread **hematogenously** (via blood) to distant sites like bone and lungs. * **Lymphoma of the Thyroid:** Usually associated with Hashimoto’s thyroiditis, its prognosis depends on the histological subtype (e.g., MALT vs. DLBCL) [2], but it does not surpass the survival rates of PTC. **3. High-Yield Clinical Pearls for NEET-PG:** * **Psammoma bodies:** Concentric calcifications seen on histology (pathognomonic for PTC). * **Orphan Annie Eye Nuclei:** Large, pale, clear nuclei seen in PTC. * **Risk Factor:** Prior exposure to ionizing radiation is the most significant risk factor for PTC. * **Genetic Association:** *BRAF* mutations (most common) and *RET/PTC* rearrangements. * **Staging:** In patients <55 years, the TNM staging system only uses Stage I and II, reflecting the excellent prognosis in younger individuals.

Q: A patient underwent thyroidectomy for hyperthyroidism. Two days later, the patient presented with features of thyroid storm. What is the most likely cause?

Inadequate preoperative preparation. ### Explanation **1. Why "Inadequate Preoperative Preparation" is correct:** The primary goal of preoperative management in hyperthyroidism (especially Graves' disease) is to achieve a **euthyroid state** before surgery. If a patient is not properly prepared with antithyroid drugs (like Carbimazole or Methimazole) and Beta-blockers, the thyroid gland remains hyperactive. Surgical manipulation of an overactive gland triggers a massive release of stored thyroid hormones (T3 and T4) into the circulation. This sudden surge precipitates a **Thyroid Storm**, a life-threatening hypermetabolic state characterized by hyperpyrexia, tachycardia, and cardiac failure. **2. Why other options are incorrect:** * **Poor antibiotic coverage:** While this increases the risk of surgical site infection or sepsis, it does not directly trigger the hormonal surge characteristic of a thyroid storm. * **Rough handling during surgery:** While excessive manipulation can exacerbate hormone release, it rarely causes a storm if the patient was adequately prepared and euthyroid. Preparation is the definitive preventive factor. * **Removal of parathyroid:** This leads to **hypocalcemia** (tetany, Chvostek’s/Trousseau’s signs), not thyroid storm. **3. Clinical Pearls for NEET-PG:** * **Lugol’s Iodine:** Often given 10 days preoperatively to decrease the **vascularity** and friability of the gland (Plummer’s effect). * **Drug of choice for Thyroid Storm:** **Propylthiouracil (PTU)** is preferred over Methimazole because it also inhibits the peripheral conversion of T4 to T3. * **Beta-blockers (Propranolol):** Essential to control adrenergic symptoms and also help inhibit peripheral T4 to T3 conversion. * **Burch-Wartofsky Point Scale:** Used clinically to diagnose and grade the severity of a thyroid storm.

Q: Which neck swelling moves on swallowing?

Thyroid gland. **Explanation:** The **Thyroid gland** is the correct answer because of its unique anatomical relationship with the **pretracheal fascia**. The thyroid is enclosed within this fascia, which is firmly attached to the **cricoid cartilage** and the **oblique line of the thyroid cartilage**. During deglutition (swallowing), the larynx and trachea are elevated by the suprahyoid muscles; because the thyroid is anchored to these structures via the pretracheal fascia (specifically the Suspensory Ligament of Berry), it moves upward along with them. **Analysis of Incorrect Options:** * **Submandibular salivary gland:** Located in the submandibular triangle, it is not attached to the laryngeal framework or the pretracheal fascia. While it may move slightly with jaw movement, it does not move with swallowing. * **Supraclavicular lymph gland:** These are located in the posterior triangle or the root of the neck and are not associated with the visceral compartment of the neck. * **Sternomastoid tumour:** This is a fibromatosis of the sternocleidomastoid muscle (often seen in congenital muscular torticollis). It is located within the carotid sheath or muscle belly and is independent of the swallowing mechanism. **Clinical Pearls for NEET-PG:** 1. **Exceptions:** Two other swellings move with swallowing: **Thyroglossal cysts** (which also move with **protrusion of the tongue** due to their attachment to the hyoid bone) and **Subhyoid bursitis**. 2. **Fixed Thyroid:** If a thyroid swelling does *not* move with swallowing, it suggests **malignant infiltration** into surrounding structures or **Riedel’s thyroiditis**. 3. **Laryngocele:** This may also move with swallowing but is typically resonant on percussion.

Q: A 20-year-old female presents with a 9-month history of neck swelling and thyrotoxic symptoms. Investigations reveal increased T4 and decreased TSH levels, with a palpable 2 cm thyroid nodule. What is the next appropriate investigation?

Thyroid scan. ### **Explanation** The clinical presentation describes a patient with **overt hyperthyroidism** (increased T4, decreased TSH) and a **palpable thyroid nodule**. In the management of a thyroid nodule, the first step is always checking the TSH level. 1. **Why Thyroid Scan is correct:** When TSH is suppressed (low), the next step is a **Thyroid Radionuclide Scan** (using Technetium-99m or Iodine-123). This determines the functional status of the nodule. If the nodule is "hot" (autonomously functioning), the risk of malignancy is extremely low (<1%), and further evaluation with FNAC is generally not required. If the nodule is "cold" (non-functioning), the risk of malignancy is higher, and an Ultrasound-guided FNAC is indicated. 2. **Why Ultrasound is incorrect:** While USG is the most sensitive tool for anatomical characterization of nodules, in the presence of hyperthyroidism, functional assessment (Scan) takes precedence to avoid unnecessary biopsy of a hot nodule. 3. **Why Radioactive Iodine Uptake (RAIU) is incorrect:** RAIU measures the percentage of iodine trapped by the *entire* gland to differentiate causes of thyrotoxicosis (e.g., Graves' vs. Thyroiditis). It does not provide the localized "hot vs. cold" map required to evaluate a specific nodule. 4. **Why CT scan is incorrect:** CT is not a primary investigation for thyroid nodules and the iodinated contrast can interfere with subsequent radioactive iodine therapy. ### **Clinical Pearls for NEET-PG** * **The "Golden Rule":** Never perform FNAC on a "Hot" nodule. * **Hot Nodule:** High uptake; low risk of malignancy; treat the hyperthyroidism. * **Cold Nodule:** Low uptake; ~15-20% risk of malignancy; proceed to FNAC. * **Most common cause of a solitary hot nodule:** Toxic Adenoma (Plummer’s disease).

Q: A 50-year-old lady presents with a thyroid swelling diagnosed as papillary carcinoma. The mass measures 4 cm at its greatest diameter and invades strap muscles. Lymph node status is negative. What is the stage of the disease?

Stage I. ### **Explanation** The staging of **Differentiated Thyroid Carcinoma (DTC)**, which includes Papillary and Follicular types, is unique because it is heavily dependent on the **age of the patient** at the time of diagnosis. According to the **AJCC 8th Edition** TNM staging system: **1. Why Stage I is Correct:** For patients **younger than 55 years**, the staging is simplified into only two categories: * **Stage I:** Any T, Any N, **M0** (No distant metastasis). * **Stage II:** Any T, Any N, **M1** (Distant metastasis present). In this case, the patient is **50 years old** (under the 55-year cutoff). Although the tumor is 4 cm and invades strap muscles (T3b), and regardless of the lymph node status (N0), the absence of distant metastasis (M0) automatically classifies this as **Stage I**. **2. Why Other Options are Incorrect:** * **Stage II:** In patients <55 years, this is reserved only for cases with distant metastasis (e.g., lung or bone spread). In patients ≥55 years, Stage II involves T1/T2 with N1 or T3 tumors. * **Stage III & IV:** These stages **do not exist** for patients under the age of 55 in the AJCC 8th edition. They are only applicable to patients ≥55 years with advanced local invasion (T4) or distant metastasis. **3. NEET-PG High-Yield Pearls:** * **Age Cutoff:** The AJCC 8th edition increased the prognostic age cutoff from **45 to 55 years**. * **T3b Definition:** Invasion of **strap muscles only** (sternohyoid, sternothyroid, thyrohyoid, or omohyoid) is classified as T3b. * **Prognosis:** Papillary carcinoma has an excellent prognosis; patients <55 years have a near 0% 10-year mortality rate if they are M0. * **Anaplastic Carcinoma:** Always remember that Anaplastic thyroid cancer is considered **Stage IV** regardless of age or size at presentation.

Question 1

Which of the following statements about anaplastic carcinoma of the thyroid is false?

Accepted Answer

It is highly chemosensitive.

Answer

It is characterized by local infiltration.

Answer

Surgery has limited value in its management.

Answer

It spreads via the lymphatic route.

Question 2

Which of the following is true regarding medullary carcinoma of the thyroid?

Accepted Answer

Elevated levels of serum calcitonin

Answer

Associated with the MET oncogene

Answer

Seen in MEN I syndrome

Answer

Most common type of thyroid cancer

Question 3

A patient undergoes thyroid surgery, following which he develops perioral tingling. His blood calcium level is 8.9 meq. What is the next best step?

Accepted Answer

Administer intravenous calcium gluconate and monitor calcium levels serially.

Answer

Administer Vitamin D orally.

Answer

Administer oral calcium and Vitamin D.

Answer

Wait for serum calcium to decrease to less than 7.0 meq before initiating further action.

Question 4

A patient has a pituitary tumor, specifically a prolactinoma, that encircles the carotid artery. What is the best line of management?

Accepted Answer

Transsphenoidal surgical resection

Answer

Observation

Answer

Radiotherapy

Answer

Medical management with dopamine agonists

Question 5

Which of the following is the most likely type of thyroid cancer with the best prognosis of all thyroid malignancies?

Accepted Answer

Papillary cancer of the thyroid

Answer

Anaplastic thyroid cancer

Answer

Follicular cancer of the thyroid

Answer

Lymphoma of the thyroid

Question 6

In retrosternal goiter, what is the most common presenting feature?

Accepted Answer

Dyspnea

Answer

Dysphagia

Answer

Stridor

Answer

Superior vena cava syndrome

Question 7

A patient underwent thyroidectomy for hyperthyroidism. Two days later, the patient presented with features of thyroid storm. What is the most likely cause?

Accepted Answer

Inadequate preoperative preparation

Answer

Poor antibiotic coverage

Answer

Rough handling during surgery

Answer

Removal of parathyroid

Question 8

Which neck swelling moves on swallowing?

Accepted Answer

Thyroid gland

Answer

Submandibular salivary gland

Answer

Supraclavicular lymph gland

Answer

Sternomastoid tumour

Question 9

A 20-year-old female presents with a 9-month history of neck swelling and thyrotoxic symptoms. Investigations reveal increased T4 and decreased TSH levels, with a palpable 2 cm thyroid nodule. What is the next appropriate investigation?

Accepted Answer

Thyroid scan

Answer

Ultrasound

Answer

Radioactive iodine uptake

Answer

CT scan

Question 10

A 50-year-old lady presents with a thyroid swelling diagnosed as papillary carcinoma. The mass measures 4 cm at its greatest diameter and invades strap muscles. Lymph node status is negative. What is the stage of the disease?

Accepted Answer

Stage I

Answer

Stage II

Answer

Stage III

Answer

Stage IV

Endocrine Surgery — MCQs

Endocrine Surgery — MCQs

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