Endocrine Pathology Practice Questions

Q: Follicular carcinoma of the thyroid is associated with mutations in which gene?

RAS. **Explanation:** Follicular Carcinoma of the Thyroid (FTC) is primarily driven by mutations in the **RAS oncogene** (specifically N-RAS, H-RAS, and K-RAS) or the **PAX8-PPARG** fusion gene [1]. RAS mutations are found in approximately 40-50% of follicular carcinomas and are also frequently seen in follicular adenomas, suggesting they are an early event in follicular tumorigenesis. **Analysis of Options:** * **A. RAS (Correct):** Mutations in the RAS family of oncogenes lead to constitutive activation of the MAPK and PI3K/AKT signaling pathways, promoting uncontrolled follicular cell proliferation [1]. * **B. HGF:** Hepatocyte Growth Factor (HGF) and its receptor MET are more commonly associated with Papillary Thyroid Carcinoma (PTC) and tumor invasion, but are not the primary drivers for FTC. * **C. RET:** Rearrangements in the *RET* gene (RET/PTC) are characteristic of **Papillary Thyroid Carcinoma** [1], while point mutations in *RET* are the hallmark of **Medullary Thyroid Carcinoma** (both sporadic and MEN 2 syndromes). * **D. ABL:** The *c-ABL* gene is typically associated with the BCR-ABL translocation (Philadelphia chromosome) seen in **Chronic Myeloid Leukemia (CML)**, not thyroid pathology. **High-Yield Clinical Pearls for NEET-PG:** * **Spread:** Unlike Papillary carcinoma (lymphatic spread), Follicular carcinoma spreads **hematogenously** (commonly to bone and lungs). * **Diagnosis:** FTC cannot be diagnosed by FNAC; histological evidence of **capsular or vascular invasion** is mandatory to differentiate it from Follicular Adenoma. * **Iodine:** FTC is more common in areas of **dietary iodine deficiency** [1]. * **Hurthle Cell Carcinoma:** A variant of FTC characterized by cells with abundant granular eosinophilic cytoplasm (due to mitochondria). **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Endocrine System, pp. 1097-1099.

Question 1

Follicular carcinoma of the thyroid is associated with mutations in which gene?

Accepted Answer

RAS

Answer

HGF

Answer

RET

Answer

ABL

Question 2

A palpable mass is noted in the right lobe of the thyroid of a 45-year-old man who visits his physician for a periodic checkup. A biopsy is performed and results in a diagnosis of medullary carcinoma of the thyroid. Which of the following histologic features of thyroid disease would most likely be present in this biopsy specimen?

Accepted Answer

Tumor cells embedded in an amyloid-laden stroma

Answer

Tumor cells with "Orphan Annie" nuclei

Answer

Psammoma bodies

Answer

Infiltrates of lymphocytes with germinal center formation

Question 3

A 35-year-old woman complains of nipple discharge and irregular menses of 5 months duration. Physical examination reveals a milky discharge from both nipples. MRI shows an enlargement of the anterior pituitary. Which of the following is the most likely histologic diagnosis of this patient's pituitary tumor?

Accepted Answer

Adenoma

Answer

Choriostoma

Answer

Hamartoma

Answer

Papilloma

Question 4

A 74-year-old woman is admitted to the hospital in an obtunded condition. Her temperature is 37°C, pulse is 95/min, respirations are 22/min, and blood pressure is 90/60 mm Hg. She appears dehydrated and has poor skin turgor. Her serum glucose level is 872 mg/dL. Urinalysis shows 4+ glucosuria, but no ketones, protein, or blood. Which of the following factors is most important in the pathogenesis of this patient's condition?

Accepted Answer

Peripheral insulin resistance

Answer

Autoimmune insulitis

Answer

Glucokinase gene mutation

Answer

HLA-DR3/HLA-DR4 genotype

Question 5

A 42-year-old woman presents with a 7-month history of increasing fullness in her neck. Physical examination reveals a diffusely and asymmetrically enlarged, nodular thyroid gland with no lymphadenopathy. Thyroidectomy is performed. Gross examination shows a multicentric thyroid neoplasm. Microscopically, the neoplasm is composed of polygonal-to spindle-shaped cells forming nests and trabeculae, with a prominent, pink hyaline stroma that stains positively with Congo red. Electron microscopy reveals intracytoplasmic, membrane-bound, electron-dense granules. Immunohistochemical staining for which of the following antigens is most useful for the diagnosis of this neoplasm?

Accepted Answer

Calcitonin

Answer

CD3

Answer

Cytokeratin

Answer

Estrogen receptor

Question 6

Congenital adrenal hyperplasia (CAH) is associated with which of the following?

Accepted Answer

Female pseudohermaphroditism

Answer

Male pseudohermaphroditism

Answer

True hermaphroditism

Answer

Cushing syndrome

Question 7

All of the following are true regarding thyroid adenoma, except?

Accepted Answer

Vascular invasion is commonly seen

Answer

Solitary, spherical and well encapsulated lesion

Answer

Uniform-appearing, colloid-containing follicles

Answer

Cystic change, calcification and Hurthle cell change

Question 8

A surgeon operates on a patient with a pheochromocytoma involving the adrenal gland and requests intraoperative frozen sections. Which of the following criteria can be used to determine if the lesion is benign or malignant?

Accepted Answer

Cannot be determined by microscopic examination

Answer

Blood vessel invasion

Answer

Hemorrhage and necrosis

Answer

Nuclear pleomorphism

Question 9

What is a diagnostic feature of parathyroid carcinoma?

Accepted Answer

Metastasis

Answer

Cytology

Answer

Clinical features

Answer

All of the above

Question 10

Sheehan syndrome is due to:

Accepted Answer

Pituitary hemorrhage

Answer

Adrenal hemorrhage

Answer

Hypothalamic hemorrhage

Answer

Pancreatic hemorrhage

Endocrine Pathology — MCQs

Endocrine Pathology — MCQs

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