Endocrine Pathology Practice Questions

Q: What is the most common cause of primary hyperparathyroidism?

Single adenoma. **Explanation:** Primary hyperparathyroidism (PHPT) is characterized by the autonomous overproduction of parathyroid hormone (PTH), leading to hypercalcemia. **1. Why "Single Adenoma" is correct:** A **solitary parathyroid adenoma** is the most frequent cause, accounting for approximately **85% to 95%** of all cases of PHPT. Pathologically, these are usually well-circumscribed, solitary nodules (often involving the inferior parathyroid glands) composed of chief cells, with a characteristic rim of compressed normal parathyroid tissue. **2. Why the other options are incorrect:** * **Multiple gland hyperplasia:** This accounts for about **10% to 15%** of cases. It typically involves all four glands and is frequently associated with familial syndromes like MEN1 or MEN2A [1]. * **Multiple adenomas:** These are rare (approx. **1%**) and involve two or more glands while others remain normal. * **Single gland hyperplasia:** This is not a standard pathological entity; hyperplasia by definition involves a proliferation of cells that typically affects multiple glands in the parathyroid context. * **Parathyroid Carcinoma:** (Not listed, but important) This is the rarest cause, occurring in <1% of cases. **High-Yield Clinical Pearls for NEET-PG:** * **Clinical Presentation:** Classically described as "Bones, Stones, Abdominal Groans, and Psychic Moans" (osteitis fibrosa cystica, nephrolithiasis, peptic ulcers, and depression). * **Biochemical Hallmark:** Elevated Serum Calcium + Elevated (or inappropriately normal) PTH + Low Serum Phosphate. * **Most common genetic mutation:** *MEN1* gene (sporadic or syndromic) and *CCND1* (Cyclin D1) inversions [1]. * **Sestamibi Scan:** The investigation of choice for localizing an adenoma before surgery. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Endocrine System, pp. 1104-1105.

Q: A 45-year-old female patient presented with features of hypothyroidism. Based on the provided histological features, what is your diagnosis?

Hashimoto thyroiditis. ***Hashimoto thyroiditis*** - Classic histological features include **lymphocytic infiltration** with **germinal center formation** and **Hürthle cell metaplasia**, consistent with hypothyroidism in a middle-aged female. - Shows **follicular atrophy** and **fibrosis**, leading to gradual thyroid dysfunction and is the most common cause of hypothyroidism in iodine-sufficient areas. *Granulomatous thyroiditis* - Characterized by **epithelioid granulomas** and **giant cells** histologically, not lymphocytic infiltration with germinal centers. - Typically presents with **painful thyroid enlargement** and **transient hyperthyroidism** followed by hypothyroidism, rather than primary hypothyroidism. *Papillary carcinoma of the thyroid* - Shows **papillary architecture** with **psammoma bodies** and **nuclear features** like overlapping, grooves, and pseudoinclusions. - Usually presents as a **thyroid nodule** rather than diffuse hypothyroidism, and patients are typically **euthyroid**. *Riedel's thyroiditis* - Characterized by **dense fibrous tissue** replacing thyroid parenchyma with **woody hardness** on palpation. - Shows **storiform fibrosis** without significant lymphocytic infiltration or germinal centers, and often involves surrounding structures.

Q: All are seen in MEN IIA syndrome except?

Caused by loss of function mutation in RET protooncogene.. **Explanation:** **MEN IIA (Sipple Syndrome)** is an autosomal dominant disorder characterized by a triad of Medullary Thyroid Carcinoma (MTC), Pheochromocytoma, and Parathyroid Hyperplasia [1]. **1. Why Option C is the correct answer (The False Statement):** MEN IIA is caused by a **gain-of-function** (activating) mutation in the **RET proto-oncogene** on chromosome 10 [1]. In contrast, "loss-of-function" mutations in the RET gene are associated with **Hirschsprung disease**. This is a high-yield distinction for NEET-PG. **2. Analysis of Incorrect Options (True Statements):** * **Option A:** MTC is the most consistent feature of MEN IIA, occurring in **100%** of patients [1]. It is often multifocal and preceded by C-cell hyperplasia. * **Option B:** Pheochromocytomas occur in approximately **40-50%** of patients [1]. They are frequently bilateral and extra-adrenal. * **Option C:** Primary hyperparathyroidism (due to hyperplasia) is seen in **10-20%** of cases. Because it occurs in the minority of patients compared to MTC and Pheochromocytoma, it is considered the **most variable** clinical feature. **Clinical Pearls for NEET-PG:** * **MEN IIA Components:** MTC + Pheochromocytoma + Parathyroid Hyperplasia [1]. * **MEN IIB Components:** MTC + Pheochromocytoma + Mucosal Neuromas/Marfanoid habitus (No parathyroid involvement) [1]. * **Prophylactic Thyroidectomy:** Recommended in children carrying the RET mutation because MTC is inevitable. * **Screening:** Always rule out Pheochromocytoma (via urinary metanephrines) before performing surgery for MTC to prevent a hypertensive crisis. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Endocrine System, p. 1137.

Q: Crook's hyaline change occurs in which of the following?

Basophils of the pituitary gland in Cushing's disease. **Explanation:** **Crooke’s hyaline change** refers to a specific morphological alteration occurring in the **ACTH-producing basophils** of the anterior pituitary gland [1]. This change is a response to chronic high levels of circulating glucocorticoids (hypercortisolism), most commonly seen in **Cushing’s syndrome** (regardless of the cause) and **Cushing’s disease** [1]. **Why it occurs:** Under the influence of excess cortisol, the normal granular cytoplasm of the basophils is replaced by a homogenous, pale, eosinophilic, and glassy material. This "hyaline" represents an accumulation of **intermediate keratin filaments** (cytokeratins), which occurs as a result of the feedback inhibition of ACTH secretion [1]. **Analysis of Incorrect Options:** * **Voluntary muscles:** Chronic steroid excess leads to muscle wasting (steroid myopathy) due to catabolism, but not "hyaline change." * **Liver in Diabetes Mellitus:** The liver in DM typically shows **steatosis** (fatty change) or glycogenated nuclei, not Crooke’s hyaline. * **Liver in Viral Hepatitis B:** This is characterized by **"Ground-glass hepatocytes"** (due to HBsAg accumulation in the ER) or **Councilman bodies** (apoptotic hepatocytes). **High-Yield Clinical Pearls for NEET-PG:** * **Microscopy:** Look for the replacement of basophilic granules with a pale, "glassy" cytoplasmic appearance [1]. * **Reversibility:** Crooke’s hyaline change is a reactive process and is potentially reversible if the source of excess cortisol is removed. * **Differential:** Do not confuse this with **Mallory-Denk bodies** (seen in alcoholic liver disease), which are also composed of intermediate filaments but occur in hepatocytes. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Endocrine System, p. 1127.

Question 1

What is the most common cause of primary hyperparathyroidism?

Accepted Answer

Single adenoma

Answer

Multiple adenomas

Answer

Single gland hyperplasia

Answer

Multiple gland hyperplasia

Question 2

A 45-year-old female patient presented with features of hypothyroidism. Based on the provided histological features, what is your diagnosis?

Accepted Answer

Hashimoto thyroiditis

Answer

Granulomatous thyroiditis

Answer

Papillary carcinoma of the thyroid

Answer

Riedel's thyroiditis

Question 3

All are seen in MEN IIA syndrome except?

Accepted Answer

Caused by loss of function mutation in RET protooncogene.

Answer

Medullary carcinoma of thyroid is seen in 100% of the patients.

Answer

40-50% patients have phaeochromocytomas.

Answer

Primary hyperparathyroidism is the most variable feature of MEN IIA syndrome.

Question 4

Pancreatitis, pituitary tumor, and pheochromocytoma may be associated with which of the following types of thyroid cancer?

Accepted Answer

Medullary carcinoma of the thyroid

Answer

Anaplastic carcinoma of the thyroid

Answer

Papillary carcinoma of the thyroid

Answer

Follicular carcinoma of the thyroid

Question 5

Carcinoid tumours commonly arise from which cell type and location?

Accepted Answer

Argentaffin cells of the small intestine

Answer

Gastrin cells in the pancreas

Answer

Pancreatic endocrine tumour

Answer

Colon polyps

Question 6

Pheochromocytomas are known to arise from all of the following locations, except:

Accepted Answer

Chest wall

Answer

Adrenal gland

Answer

Mediastinum

Answer

Neck

Question 7

All of the following are seen in follicular carcinoma of the thyroid, except?

Accepted Answer

Point mutations of TP53

Answer

PAX8-PPARG fusion

Answer

RAS gene mutations

Answer

Loss-of-function mutations of PTEN gene

Question 8

Crook's hyaline change occurs in which of the following?

Accepted Answer

Basophils of the pituitary gland in Cushing's disease

Answer

Voluntary muscles

Answer

Liver in diabetes mellitus

Answer

Liver in viral hepatitis B

Question 9

A female neonate with DiGeorge syndrome develops severe muscle cramps and convulsions soon after birth. Which of the following is the cause of convulsions in this neonate?

Accepted Answer

Hypocalcemia

Answer

Acute hemorrhagic adrenalitis

Answer

Hypoglycemia

Answer

Hypokalemia

Question 10

Hürthle cell carcinoma is a variant of which thyroid carcinoma?

Accepted Answer

Follicular carcinoma

Answer

Medullary carcinoma

Answer

Papillary carcinoma

Answer

Anaplastic carcinoma

Endocrine Pathology — MCQs

Endocrine Pathology — MCQs

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