Endocrine Pathology — MCQs

Endocrine Pathology Indian Medical PG Practice Questions and MCQs

Question 131: What is the goitrous form of autoimmune thyroiditis called?

A. Myxoedema.
B. Hashimoto's disease. (Correct Answer)
C. Riedel's thyroiditis.
D. All of the above.

Explanation: **Explanation:** **Hashimoto’s Thyroiditis** (Chronic Lymphocytic Thyroiditis) is the most common cause of hypothyroidism in iodine-sufficient regions. It is an autoimmune disorder characterized by the destruction of thyroid cells by cell-mediated and humoral immune processes. It typically presents in two clinical forms: 1. **Goitrous Form:** Characterized by a diffuse, painless enlargement of the thyroid gland (goiter) [1]. This is the classic **Hashimoto’s disease**. 2. **Atrophic Form:** Characterized by a small, fibrotic thyroid gland, often representing the end-stage of the inflammatory process. **Analysis of Options:** * **Hashimoto’s Disease (Correct):** It is the definitive "goitrous form" of autoimmune thyroiditis. Histologically, it shows intense lymphocytic infiltration with germinal center formation and the presence of **Hürthle cells** (oxyphilic, eosinophilic granular cytoplasm) [1]. * **Myxoedema:** This refers to the clinical state of severe hypothyroidism characterized by non-pitting edema. While Hashimoto’s can lead to myxoedema, it is a clinical manifestation/complication, not the name of the goitrous disease itself. * **Riedel’s Thyroiditis:** This is a rare condition characterized by extensive systemic fibrosis (IgG4-related disease) where the thyroid is replaced by dense fibrous tissue ("woody" or "iron-hard" thyroid). It is not primarily classified as an autoimmune lymphocytic thyroiditis. **NEET-PG High-Yield Pearls:** * **Antibodies:** Anti-Thyroid Peroxidase (Anti-TPO) and Anti-Thyroglobulin (Anti-Tg) are hallmarks. * **Genetics:** Associated with **HLA-DR3** and **HLA-DR5**. * **Risk:** Increased risk of **B-cell Non-Hodgkin Lymphoma** (specifically MALToma) and Papillary Thyroid Carcinoma. * **Cytology:** Look for "Hurthle cells" (metaplastic follicular cells) and "Lymphocytic clusters" [1]. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Liver And Biliary System Disease, pp. 427-428.

Question 132: Which of the following statements is true about pituitary adenoma?

A. Accounts for 10% of brain tumors
B. Erodes the sellar and extends into surrounding areas (Correct Answer)
C. Prolactinoma is the least common type
D. It is differentiated by reticulin stain

Explanation: **Explanation:** Pituitary adenomas are common benign neoplasms of the anterior pituitary. The correct statement is that they can **erode the sella turcica and extend into surrounding areas** [2]. As these tumors grow (especially macroadenomas >10mm), they exert pressure on the bony walls of the sella, leading to erosion and expansion [2]. They frequently extend superiorly into the suprasellar space, compressing the optic chiasm (causing bitemporal hemianopsia) [1], [2], or laterally into the cavernous sinuses. **Analysis of Options:** * **Option A:** Pituitary adenomas actually account for approximately **10% to 15%** of all intracranial neoplasms, making them the most common tumor in the sellar region. * **Option C:** Prolactinoma is the **most common** type of functioning pituitary adenoma (approx. 30%), followed by growth hormone-secreting adenomas [1], [2]. * **Option D:** This is a common distractor. Pituitary adenomas are characterized by the **loss/disruption of the reticulin network**. While the reticulin stain is used to *diagnose* them, the statement "it is differentiated by reticulin stain" is often used to describe the *absence* of the normal acinar reticulin pattern seen in the healthy pituitary gland. **High-Yield NEET-PG Pearls:** * **Morphology:** Monomorphism (cells look identical) and absence of a reticulin network are the hallmarks of an adenoma. * **Genetics:** Mutations in the **GNAS1** gene (encoding the Gsα protein) are found in 40% of somatotroph (GH) adenomas. * **MEN1 Syndrome:** Pituitary adenomas are a component of the "3 Ps" (Pituitary, Parathyroid, Pancreas). * **Clinical:** The "classic" presentation of a macroadenoma is **bitemporal hemianopsia** due to optic chiasm compression [1], [2]. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Liver And Biliary System Disease, pp. 417-418. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Endocrine System, p. 1081.

Question 133: Amyloid deposition is characteristic of which of the following conditions?

A. Medullary carcinoma of the thyroid (Correct Answer)
B. Acute liver failure
C. Cirrhosis
D. Budd-Chiari syndrome

Explanation: **Explanation:** **Medullary Carcinoma of the Thyroid (MTC)** is a neuroendocrine tumor derived from the **parafollicular C-cells**, which secrete the hormone **calcitonin**. The characteristic amyloid deposition seen in MTC is "procalcitonin-derived amyloid." [1] Excess calcitonin undergoes misfolding and aggregates into insoluble fibrils, which deposit within the tumor stroma. [3] On histopathology, this appears as extracellular eosinophilic material that shows **apple-green birefringence** under polarized light when stained with **Congo Red**. [2] **Analysis of Incorrect Options:** * **Acute Liver Failure:** Characterized by massive hepatic necrosis and cerebral edema, but not amyloid deposition. * **Cirrhosis:** Defined by diffuse fibrosis and regenerative nodules. While chronic inflammation can lead to systemic AA amyloidosis, cirrhosis itself is not characterized by localized amyloid deposition. * **Budd-Chiari Syndrome:** Caused by hepatic vein obstruction leading to post-sinusoidal portal hypertension. The pathology involves centrilobular congestion and necrosis, not amyloid. **High-Yield Clinical Pearls for NEET-PG:** * **Origin:** Parafollicular C-cells (Ultimobranchial body). * **Genetics:** Associated with **RET proto-oncogene** mutations (MEN 2A and 2B syndromes). [1] * **Tumor Marker:** Serum **Calcitonin** is used for diagnosis and monitoring recurrence. [1] * **Staining:** Congo Red (Apple-green birefringence) and Immunohistochemistry for Calcitonin. [2] * **Microscopy:** Polygonal to spindle-shaped cells in nests (Zellballen pattern) or cords, separated by amyloid stroma. [1] **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Endocrine System, pp. 1102-1103. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of the Immune System, pp. 268-269. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of the Immune System, pp. 264-266.

Question 134: Which of the following is not a histological variant of thyroid neoplasm?

A. Follicular
B. Merkel cell (Correct Answer)
C. Insular
D. Anaplastic

Explanation: The correct answer is **Merkel cell** because it is a primary neuroendocrine carcinoma of the **skin**, not the thyroid gland. ### **Detailed Explanation** **1. Why Merkel Cell is the Correct Answer:** Merkel cell carcinoma is a rare, aggressive cutaneous malignancy derived from mechanoreceptor cells in the basal layer of the epidermis. While it is a neuroendocrine tumor, it does not originate in the thyroid. In the context of thyroid pathology, the primary neuroendocrine tumor is **Medullary Thyroid Carcinoma (MTC)**, which arises from parafollicular C-cells [1]. **2. Analysis of Incorrect Options:** * **Follicular (Option A):** This is a major category of thyroid neoplasm [4]. It includes Follicular Adenoma (benign) and Follicular Thyroid Carcinoma (malignant), characterized by the formation of follicles without the nuclear features of papillary carcinoma [1], [3]. * **Insular (Option B):** This is a specific histological variant of **Poorly Differentiated Thyroid Carcinoma (PDTC)**. It is characterized by "islands" (insulae) of small, uniform cells and carries a prognosis intermediate between well-differentiated and anaplastic carcinomas. * **Anaplastic (Option D):** This is an undifferentiated, highly aggressive thyroid malignancy [4]. Histologically, it presents with pleomorphic giant cells, spindle cells, or squamoid features [2]. ### **NEET-PG High-Yield Pearls** * **Most common thyroid cancer:** Papillary Thyroid Carcinoma (associated with *Orphan Annie eye* nuclei and *Psammoma bodies*) [4]. * **Insular Carcinoma marker:** Often shows positivity for **Thyroglobulin**, helping distinguish it from Medullary carcinoma. * **Merkel Cell Carcinoma marker:** Characteristically expresses **CK20** in a "perinuclear dot-like" pattern. * **Medullary Carcinoma marker:** Calcitonin and Amyloid stroma (Congo Red positive) [2]. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Liver And Biliary System Disease, pp. 428-429. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Liver And Biliary System Disease, pp. 430-431. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Endocrine System, pp. 1099-1100. [4] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Liver And Biliary System Disease, pp. 429-430.

Question 135: Vanillylmandelic acid (VMA) is increased in which of the following conditions?

A. Parathyroidism
B. Pheochromocytoma (Correct Answer)
C. Multiple Endocrine Neoplasia type 1 (MEN-1)
D. Addison's disease

Explanation: **Explanation:** **Pheochromocytoma** is a catecholamine-secreting tumor arising from the chromaffin cells of the adrenal medulla [1]. The correct answer is B because **Vanillylmandelic acid (VMA)** is the major end-stage metabolic byproduct of catecholamines (epinephrine and norepinephrine). In pheochromocytoma, the excessive production and subsequent degradation of these catecholamines by the enzymes Monoamine Oxidase (MAO) and Catechol-O-methyltransferase (COMT) lead to significantly elevated levels of VMA in a 24-hour urine collection [2]. **Analysis of Incorrect Options:** * **A. Parathyroidism:** Hyperparathyroidism involves excess Parathyroid Hormone (PTH), leading to hypercalcemia and hyperphosphaturia, but has no direct link to catecholamine metabolism. * **C. MEN-1 (Wermer Syndrome):** This syndrome is characterized by the "3 Ps": Pituitary, Parathyroid, and Pancreatic tumors. While Pheochromocytoma is associated with **MEN-2A and 2B**, it is not a feature of MEN-1. * **D. Addison’s Disease:** This is primary adrenocortical insufficiency (deficiency of cortisol and aldosterone). It typically results in low blood pressure and electrolyte imbalances, rather than an increase in catecholamine metabolites. **High-Yield Clinical Pearls for NEET-PG:** * **Gold Standard Screening:** While VMA was traditionally used, **Urinary or Plasma Fractionated Metanephrines** are now considered more sensitive and are the preferred initial screening test for Pheochromocytoma. * **Rule of 10s:** Pheochromocytoma is 10% bilateral, 10% malignant, 10% pediatric, 10% extra-adrenal (Paraganglioma), and 10% familial. * **Zellballen Pattern:** On histopathology, tumor cells are arranged in small nests or "balls" surrounded by a vascular stroma [2]. * **Clinical Triad:** Episodic headache, sweating (diaphoresis), and tachycardia in a patient with hypertension [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Endocrine System, pp. 1138-1139. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Liver And Biliary System Disease, pp. 419-420.

Question 136: The histopathologic feature of medullary carcinoma of the thyroid is:

A. Anaplasia
B. Mitotic figures
C. Psammoma bodies
D. Amyloid stroma (Correct Answer)

Explanation: **Explanation:** **Medullary Thyroid Carcinoma (MTC)** is a neuroendocrine neoplasm derived from the **parafollicular C-cells** of the thyroid [1]. These cells are responsible for secreting **calcitonin** [1]. 1. **Why Amyloid Stroma is Correct:** The hallmark of MTC is the presence of an acellular, eosinophilic **amyloid stroma**. This amyloid is unique because it is formed by the deposition of **procalcitonin** (altered calcitonin) molecules. On histology, these deposits appear as pink, amorphous material that shows **apple-green birefringence** under polarized light when stained with **Congo Red**. 2. **Why Other Options are Incorrect:** * **Anaplasia:** This is a feature of Anaplastic Thyroid Carcinoma, which shows extreme pleomorphism and giant cells, rather than MTC. * **Mitotic Figures:** While present in aggressive tumors, they are not a diagnostic or pathognomonic feature of MTC. * **Psammoma Bodies:** These are laminated calcifications characteristic of **Papillary Thyroid Carcinoma (PTC)**. They are almost never seen in MTC. **High-Yield Clinical Pearls for NEET-PG:** * **Origin:** Neural crest cells (C-cells). * **Genetics:** Associated with **RET proto-oncogene** mutations. It occurs in **MEN 2A and 2B** syndromes (familial cases are often bilateral/multicentric) [2]. * **Tumor Marker:** Serum **Calcitonin** (used for diagnosis and monitoring recurrence) and CEA [2]. * **Histology:** Polygonal to spindle-shaped cells in nests (Zellballen pattern), follicles, or sheets. * **IHC Markers:** Positive for Calcitonin, Chromogranin A, and Synaptophysin. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Liver And Biliary System Disease, pp. 428-429. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Endocrine System, pp. 1102-1103.

Question 137: All of the following are features of MEN 1 syndrome except?

A. Pancreatic tumor
B. Pituitary tumor
C. Hyperparathyroidism
D. Medullary carcinoma of thyroid (Correct Answer)

Explanation: **Explanation:** Multiple Endocrine Neoplasia (MEN) syndromes are autosomal dominant disorders characterized by tumors involving two or more endocrine glands. **Why Option D is the correct answer:** **Medullary Carcinoma of Thyroid (MTC)** is the hallmark feature of **MEN 2A and MEN 2B**, not MEN 1 [1]. MTC in these syndromes is typically multicentric and associated with *RET* proto-oncogene mutations. In MEN 1, the genetic defect involves the *MEN1* gene (encoding the protein Menin) on chromosome 11q13, which does not predispose to MTC [2]. **Why the other options are incorrect:** MEN 1 syndrome, also known as **Wermer Syndrome**, is classically defined by the **"3 Ps"**: * **Hyperparathyroidism (Option C):** The most common (95%) and usually the earliest manifestation [2]. It typically presents as multiglandular parathyroid hyperplasia. * **Pancreatic Neuroendocrine Tumors (Option A):** These are the leading cause of morbidity/mortality in MEN 1. Common types include Gastrinomas (Zollinger-Ellison Syndrome) and Insulinomas [2]. * **Pituitary Tumors (Option B):** Most commonly Prolactinomas, followed by Somatotropinomas (causing Acromegaly). **High-Yield Clinical Pearls for NEET-PG:** * **MEN 1 (Wermer):** 3 Ps (Parathyroid, Pancreas, Pituitary). Gene: *MEN1* (Chromosome 11q13) [2]. * **MEN 2A (Sipple):** 2 Ps (Parathyroid, Pheochromocytoma) + MTC. Gene: *RET* [1]. * **MEN 2B:** 1 P (Pheochromocytoma) + MTC + Mucosal Neuromas/Marfanoid habitus. Gene: *RET* [1]. * **Key Distinction:** Parathyroid involvement is common in MEN 1 and 2A, but **absent** in MEN 2B [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Endocrine System, p. 1137. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Endocrine System, pp. 1104-1105, 1125.

Question 138: Which of the following is not directly related to Hashimoto's thyroiditis?

A. Hypothyroidism
B. Slow onset
C. Neuropathy (Correct Answer)
D. Autoimmune disease

Explanation: **Explanation:** Hashimoto’s Thyroiditis (Chronic Lymphocytic Thyroiditis) is the most common cause of hypothyroidism in iodine-sufficient regions [1]. It is characterized by the autoimmune destruction of the thyroid gland [1]. **Why Neuropathy is the Correct Answer:** Neuropathy is **not** a direct pathological feature or a primary diagnostic criterion for Hashimoto’s thyroiditis [2]. While severe, long-standing hypothyroidism (myxedema) can lead to secondary complications like Carpal Tunnel Syndrome (due to deposition of mucopolysaccharides) [2] or "hung-up" deep tendon reflexes, neuropathy itself is not a direct mechanism of the disease. In contrast, Hashimoto's is fundamentally defined by its autoimmune nature and its effect on thyroid function. **Analysis of Other Options:** * **A. Hypothyroidism:** This is the clinical hallmark. The destruction of thyroid follicles by CD8+ T-cells and autoantibodies eventually leads to primary thyroid failure [1]. * **B. Slow onset:** Hashimoto’s is a chronic, progressive disease. It typically presents as a gradual, painless enlargement of the thyroid (goiter) with slowly evolving symptoms of thyroid deficiency [1]. * **D. Autoimmune disease:** It is a Type IV (cell-mediated) and Type II (antibody-mediated) hypersensitivity reaction [1]. Key markers include Anti-TPO (Antithyroid peroxidase) and Anti-Tg (Antithyroglobulin) antibodies. **NEET-PG High-Yield Pearls:** * **Histology:** Look for **Hurthle cells** (Askanazy cells)—eosinophilic, granular cytoplasm—and dense **lymphocytic infiltrates** with germinal centers [1]. * **Genetic Association:** Linked with **HLA-DR3** and **HLA-DR5**. * **Risk of Malignancy:** Patients have an increased risk of developing **B-cell Non-Hodgkin Lymphoma** (specifically MALToma) and potentially Papillary Thyroid Carcinoma [1]. * **Pathogenesis:** Mediated by cytotoxic T-cells and cytokines (IFN-γ) [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Endocrine System, pp. 1089-1091. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Liver And Biliary System Disease, pp. 426-428.

Question 139: Amyloid deposition is seen in which type of thyroid carcinoma?

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

Explanation: **Explanation:** **Medullary Thyroid Carcinoma (MTC)** is the correct answer because it originates from the **Parafollicular C-cells** [3], which are neuroendocrine cells responsible for secreting the hormone **Calcitonin** [1]. In MTC, excessive calcitonin molecules undergo misfolding and aggregate to form pro-amyloid fibrils. These are deposited within the tumor stroma as **localized amyloid**, which stains positive with **Congo Red** (showing apple-green birefringence under polarized light) [2]. This is a classic diagnostic hallmark of MTC. **Why other options are incorrect:** * **Papillary Carcinoma (B):** The most common thyroid cancer, characterized by "Orphan Annie eye" nuclei and **Psammoma bodies** (laminated calcifications), not amyloid. * **Follicular Carcinoma (A):** Characterized by follicular architecture with capsular or vascular invasion [2]. It does not involve neuroendocrine secretions that lead to amyloidosis. * **Anaplastic Carcinoma (C):** A highly aggressive, undifferentiated tumor composed of pleomorphic giant cells or spindle cells [2]. It lacks the secretory machinery to produce amyloid. **High-Yield Clinical Pearls for NEET-PG:** * **Origin:** Derived from C-cells (Ultimobranchial body) [3]. * **Genetics:** Associated with **RET proto-oncogene** mutations. It occurs in **MEN 2A and 2B** syndromes [1]. * **Tumor Marker:** Serum Calcitonin is used for diagnosis and monitoring recurrence [1]. * **Histology:** Nests of polygonal cells in a prominent fibrovascular stroma containing amyloid [2]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Endocrine System, pp. 1102-1103. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Liver And Biliary System Disease, pp. 430-431. [3] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Liver And Biliary System Disease, pp. 428-429.

Question 140: Which of the following statements is NOT true regarding medullary carcinoma of the thyroid?

A. Originates from the C cells of the thyroid
B. Is a component of Multiple Endocrine Neoplasia type 1 (MEN-1) (Correct Answer)
C. Typically multicentric in origin
D. Characterized by amyloid deposition

Explanation: **Explanation:** Medullary Thyroid Carcinoma (MTC) is a neuroendocrine tumor that accounts for approximately 5% of thyroid malignancies [2]. **Why Option B is the Correct Answer (The False Statement):** Medullary Thyroid Carcinoma is associated with **MEN-2A and MEN-2B** syndromes, not MEN-1 [1]. MEN-1 (Wermer Syndrome) typically involves the "3 Ps": Pituitary adenoma, Parathyroid hyperplasia, and Pancreatic islet cell tumors [3]. MTC is the hallmark feature of MEN-2, caused by germline mutations in the **RET proto-oncogene**. **Analysis of Other Options:** * **Option A:** MTC originates from the **parafollicular C cells**, which are neuroendocrine cells derived from the ultimobranchial body [2]. These cells secrete **calcitonin**, which serves as a crucial tumor marker for diagnosis and monitoring [1]. * **Option C:** While sporadic MTC is usually solitary, **familial cases** (associated with MEN syndromes) are characteristically **multicentric and bilateral**, often preceded by C-cell hyperplasia. * **Option D:** A classic histological feature of MTC is the presence of **amyloid deposits** in the stroma [2]. This amyloid is derived from altered calcitonin molecules and stains positive with **Congo Red**, showing apple-green birefringence under polarized light. **High-Yield Clinical Pearls for NEET-PG:** 1. **Genetic Link:** 75% of cases are sporadic; 25% are familial (MEN-2A, 2B, or FMTC) [1]. 2. **Tumor Marker:** Calcitonin is used for diagnosis; CEA is used for monitoring prognosis [1]. 3. **Histology:** Nests of polygonal cells (Zellballen pattern) with "salt and pepper" chromatin. 4. **Prophylaxis:** In patients with known RET mutations, prophylactic thyroidectomy is often indicated. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Endocrine System, pp. 1102-1103. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Liver And Biliary System Disease, pp. 428-431. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Endocrine System, pp. 1139-1140.

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Pituitary Gland Disorders

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Thyroid Gland Diseases

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Parathyroid Gland Pathology

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Adrenal Medullary Disorders

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Pancreatic Endocrine Disorders

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Diffuse Neuroendocrine System

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Laboratory Diagnosis of Endocrine Diseases

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