Endocrine Pathology Practice Questions

Q: Which of the following is a fibrosing type of thyroiditis?

Riedel's thyroiditis. **Explanation:** **Riedel’s Thyroiditis** is the correct answer because it is characterized by extensive **dense fibrous tissue replacement** of the thyroid parenchyma [1]. This fibrosis often extends beyond the thyroid capsule into adjacent neck structures (trachea, esophagus, recurrent laryngeal nerve), mimicking a malignancy [1]. It is now considered a manifestation of **IgG4-related systemic disease** [1]. On palpation, the thyroid is classically described as "stony hard" and fixed [1]. **Why other options are incorrect:** * **Hashimoto’s Thyroiditis:** While late-stage Hashimoto’s can show some fibrosis, its hallmark is **lymphocytic infiltration** with germinal center formation and the presence of **Hürthle cells** (oxyphilic metaplasia). It is the most common cause of hypothyroidism in iodine-sufficient areas. * **De Quervain’s Thyroiditis (Subacute Granulomatous):** This is typically a post-viral inflammatory condition. Histologically, it is characterized by **granulomatous inflammation** with multinucleated giant cells surrounding fragments of colloid, rather than extensive fibrosis. It is clinically associated with a painful, tender thyroid. **NEET-PG High-Yield Pearls:** * **Riedel’s Thyroiditis:** Look for the "Hard as wood/iron" thyroid. It is associated with other fibrosing conditions like retroperitoneal fibrosis, sclerosing cholangitis, and mediastinal fibrosis [1]. * **Microscopy:** Riedel's shows a dense collagenous stroma with a sparse inflammatory infiltrate (lymphocytes, plasma cells, and eosinophils). * **Differential:** Must be differentiated from the **fibrosing variant of Hashimoto’s** and **Anaplastic Carcinoma**; however, Riedel’s lacks the cellular atypia seen in malignancy. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Endocrine System, pp. 1091-1092.

Q: Papillary carcinoma of the thyroid primarily spreads via which route?

Lymphatic. **Explanation:** **1. Why Lymphatic is Correct:** Papillary Thyroid Carcinoma (PTC) is the most common type of thyroid malignancy. Its hallmark characteristic is a strong predilection for **lymphatic spread**. Approximately 50-80% of patients have microscopic cervical lymph node involvement at the time of diagnosis. It typically spreads to the central compartment (Level VI) first, followed by the lateral neck nodes (Levels II-V). This occurs because the tumor cells easily invade the rich lymphatic network of the thyroid gland. **2. Why Other Options are Incorrect:** * **Hematogenous:** While PTC can spread via the blood, this is **rare** (seen in <5% of cases) and usually occurs late in the disease, primarily to the lungs and bones. In contrast, **Follicular Carcinoma** is the thyroid malignancy known for early hematogenous spread. * **Local Spread:** While PTC can invade the thyroid capsule and adjacent structures (like the trachea or recurrent laryngeal nerve), this is a feature of advanced T4 disease rather than the primary mode of metastasis. * **All of the Above:** Although all routes are theoretically possible, the question asks for the *primary* route. Lymphatic spread is the defining metastatic pathway for PTC. **3. High-Yield Clinical Pearls for NEET-PG:** * **Psammoma Bodies:** These are pathognomonic laminated calcifications often seen in PTC (representing infarcted papillae). * **Orphan Annie Eye Nuclei:** A classic histological finding (large, pale, clear nuclei). * **Prognosis:** Despite frequent lymph node metastasis, PTC has an excellent 10-year survival rate (>90%). * **Risk Factor:** Prior exposure to ionizing radiation is the most significant risk factor. * **BRAF Mutation:** The V600E mutation is the most common genetic alteration in PTC and is associated with a higher risk of lymph node metastasis.

Q: A 24-year-old male presented with a swelling on the anterior aspect of the neck. On examination, the swelling was firm and moved with deglutition. A biopsy from the lesion is shown. What is the typical finding and diagnosis?

Orphan Annie eye nuclei; Papillary carcinoma of the thyroid. ***Orphan Annie eye nuclei; Papillary carcinoma of the thyroid*** - **Orphan Annie eye nuclei** (ground-glass, empty-appearing nuclei with prominent nucleoli) are the **hallmark histological feature** of papillary thyroid carcinoma. - The clinical presentation of a **firm neck swelling that moves with deglutition** in a young male is classic for papillary thyroid carcinoma, the most common thyroid malignancy. *Orphan Annie eye nuclei; Follicular carcinoma of the thyroid* - While **Orphan Annie eye nuclei** are correctly identified, they are **pathognomonic for papillary carcinoma**, not follicular carcinoma. - **Follicular carcinoma** shows **microfollicular architecture** with **capsular and vascular invasion**, lacking the characteristic nuclear features of papillary carcinoma. *Hurthle cell change; Follicular carcinoma of the thyroid* - **Hurthle cell change** (oncocytic cells with abundant eosinophilic cytoplasm) can occur in various thyroid conditions but is **not the primary histological feature** described here. - The **nuclear morphology** (Orphan Annie eye nuclei) is more specific for diagnosis than cytoplasmic changes like Hurthle cell transformation. *Hurthle cell change; Papillary carcinoma of the thyroid* - While papillary carcinoma can occasionally show **Hurthle cell features**, the **primary diagnostic criterion** is the **nuclear morphology** (Orphan Annie eye nuclei). - **Hurthle cell change** is a **secondary feature** and not the **pathognomonic finding** that defines papillary thyroid carcinoma.

Question 1

Which of the following is a fibrosing type of thyroiditis?

Accepted Answer

Riedel's thyroiditis

Answer

Hashimoto's thyroiditis

Answer

De Quervain's thyroiditis

Answer

All of the above

Question 2

Which of the following findings is not seen in hyperparathyroidism?

Accepted Answer

Punched-out lesions of the skull

Answer

Osteopenia

Answer

Renal stones

Answer

Brown tumors

Question 3

Papillary carcinoma of the thyroid primarily spreads via which route?

Accepted Answer

Lymphatic

Answer

Hematogenous

Answer

Local spread

Answer

All of the above

Question 4

Subperiosteal bone resorption is seen in which of the following conditions?

Accepted Answer

Hyperparathyroidism

Answer

Hypothyroidism

Answer

Hyperthyroidism

Answer

Hypoparathyroidism

Question 5

Which of the following is the most characteristic ultrastructural feature of paraganglioma on electron microscopy?

Accepted Answer

Dense core neuroendocrine granules

Answer

Shrunken mitochondria

Answer

Large Golgi apparatus

Answer

Frequent mitoses

Question 6

A 21-year-old pregnant woman experiences abruptio placentae at 37 weeks of gestation and develops severe vaginal bleeding that is difficult to control. Five months later, the patient presents with profound lethargy, pallor, muscle weakness, failure of lactation, and amenorrhea. Which of the following best explains the pathogenesis of pituitary insufficiency in this patient?

Accepted Answer

Infarction

Answer

Abscess

Answer

Embolism

Answer

Passive hyperemia

Question 7

A 24-year-old male presented with a swelling on the anterior aspect of the neck. On examination, the swelling was firm and moved with deglutition. A biopsy from the lesion is shown. What is the typical finding and diagnosis?

Accepted Answer

Orphan Annie eye nuclei; Papillary carcinoma of the thyroid

Answer

Orphan Annie eye nuclei; Follicular carcinoma of the thyroid

Answer

Hurthle cell change; Follicular carcinoma of the thyroid

Answer

Hurthle cell change; Papillary carcinoma of the thyroid

Question 8

Orphan Annie-eye nuclei are seen in which of the following conditions?

Accepted Answer

Papillary carcinoma of thyroid

Answer

Medullary carcinoma of thyroid

Answer

Anaplastic carcinoma of thyroid

Answer

Follicular carcinoma of thyroid

Question 9

What is characteristic of parathyroid carcinoma?

Accepted Answer

Increased parathormone, decreased calcium in bone

Answer

5-10% incidence

Answer

Cytology is diagnostic

Answer

Metastasis is essential

Question 10

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

Accepted Answer

Most cases are sporadic.

Answer

It is a tumor arising from C cells derived from the neural crest.

Answer

It secretes high levels of calcitonin.

Answer

It is not dependent on TSH.

Endocrine Pathology — MCQs

Endocrine Pathology — MCQs

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