Endocrine Pathology Practice Questions

Q: A 70-year-old male presented to the OPD with fatigue. His fasting blood glucose was 110 mg/dL, postprandial glucose was 180 mg/dL, and HbA1c was 6.1%. What is your diagnosis?

Prediabetes. **Explanation:** The diagnosis of **Prediabetes** is based on the ADA (American Diabetes Association) criteria, which define a state where blood glucose levels are higher than normal but do not yet meet the threshold for Diabetes Mellitus [1]. **1. Why Prediabetes is correct:** The patient’s values fall precisely within the prediabetic ranges [1]: * **Impaired Fasting Glucose (IFG):** 100–125 mg/dL (Patient: 110 mg/dL). * **Impaired Glucose Tolerance (IGT):** 2-hour postprandial (or OGTT) 140–199 mg/dL (Patient: 180 mg/dL). * **HbA1c:** 5.7% to 6.4% (Patient: 6.1%). Since all three parameters align with these ranges, prediabetes is the definitive diagnosis. **2. Why other options are incorrect:** * **Normal Glucose Tolerance:** Normal values are Fasting <100 mg/dL, 2-hr PP <140 mg/dL, and HbA1c <5.7%. This patient exceeds all these limits. * **Diabetes Mellitus:** Requires Fasting ≥126 mg/dL, 2-hr PP ≥200 mg/dL, or HbA1c ≥6.5%. The patient’s values are below these cut-offs [1]. * **Stress-induced Hyperglycemia:** This is a transient rise in glucose due to acute illness (e.g., sepsis, MI). The patient presents with chronic fatigue and an elevated HbA1c, which reflects average glycemia over 3 months, ruling out an acute stress response. **High-Yield Clinical Pearls for NEET-PG:** * **HbA1c Limitations:** It can be falsely low in conditions with high red cell turnover (e.g., Hemolytic anemia, Pregnancy) and falsely high in Iron deficiency anemia. * **Screening:** In asymptomatic adults, screening for prediabetes/diabetes should begin at age 35 (revised from 45). * **Conversion:** Prediabetes carries a high risk of progression to Type 2 DM (approx. 5-10% per year) and is already associated with an increased risk of cardiovascular disease [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Endocrine System, pp. 1109-1111.

Q: In the thyroid gland, the colloid material is predominantly composed of which of the following?

Thyroglobulin. **Explanation:** **1. Why Thyroglobulin is Correct:** The thyroid follicle is the functional unit of the thyroid gland. The central lumen of these follicles is filled with **colloid**, a viscous fluid. The primary constituent of this colloid is **Thyroglobulin (Tg)** [1], a large dimeric glycoprotein synthesized by the follicular epithelial cells. Thyroglobulin acts as a scaffold for thyroid hormone synthesis and a storage form of iodine. It contains tyrosine residues that undergo iodination to eventually form T3 and T4. **2. Why Other Options are Incorrect:** * **Thyroxine (T4):** While T4 is the major hormone produced by the thyroid, it is stored *within* the thyroglobulin molecule in the colloid. It is not the "predominant material" itself but a product cleaved from Tg before secretion into the blood. * **Monoiodotyrosine (MIT) & Diiodotyrosine (DIT):** These are intermediate iodinated tyrosine residues found attached to the thyroglobulin backbone. They are precursors to T3 and T4 and do not exist independently as the bulk of the colloid. **3. High-Yield Clinical Pearls for NEET-PG:** * **PAS Staining:** Thyroid colloid is strongly **PAS (Periodic Acid-Schiff) positive** [1] due to the high carbohydrate content of thyroglobulin. * **Scalloping:** In hyperactive states (like Graves' disease), the colloid shows "peripheral scalloping" or "moth-eaten" appearance due to rapid endocytosis of thyroglobulin by follicular cells. * **Tumor Marker:** Serum thyroglobulin is used as a tumor marker to monitor the recurrence of **Papillary and Follicular thyroid carcinomas** after total thyroidectomy. * **Site of Action:** The coupling of MIT and DIT occurs at the apical surface/colloid interface, catalyzed by **Thyroid Peroxidase (TPO)**. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Endocrine System, pp. 1085-1086.

Q: Amyloidosis is most commonly seen in which type of Diabetes Mellitus?

Type II diabetes mellitus. **Explanation:** The correct answer is **Type II Diabetes Mellitus (T2DM)**. The hallmark pathological finding in the pancreatic islets of patients with T2DM is the deposition of **Amyloid**. **1. Why Type II Diabetes Mellitus is correct:** In T2DM, there is a state of insulin resistance leading to the hypersecretion of insulin by pancreatic beta cells. Insulin is co-secreted with a regulatory peptide called **Amylin** (also known as **Islet Amyloid Polypeptide or IAPP**). In chronic T2DM, this excessive production leads to the misfolding and aggregation of IAPP into insoluble amyloid fibrils [1]. These deposits are found in the extracellular space of the Islets of Langerhans, eventually leading to beta-cell replacement and atrophy. **2. Why other options are incorrect:** * **Type I Diabetes Mellitus:** This is an autoimmune condition characterized by the destruction of beta cells. The typical pathology shows **Insulitis** (lymphocytic infiltration) rather than amyloidosis [1]. * **Maturity Onset Diabetes of the Young (MODY):** This refers to a group of monogenic disorders resulting in beta-cell dysfunction. It does not typically involve the amyloid deposition seen in the polygenic T2DM. * **Hypertension:** While often comorbid with T2DM (Metabolic Syndrome), hypertension itself causes **Hyaline Arteriolosclerosis** in the kidneys and other organs, not pancreatic amyloidosis [1]. **High-Yield NEET-PG Pearls:** * **Amyloid Type:** The specific amyloid in T2DM is **AIAPP** (Amylin). * **Staining:** Like all amyloid, it shows **Apple-green birefringence** under polarized light after **Congo Red staining**. * **Pathological Progression:** Islet amyloidosis is present in over 90% of T2DM patients at autopsy and correlates with the severity of the disease. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Endocrine System, pp. 1119-1123.

Question 1

A 70-year-old male presented to the OPD with fatigue. His fasting blood glucose was 110 mg/dL, postprandial glucose was 180 mg/dL, and HbA1c was 6.1%. What is your diagnosis?

Accepted Answer

Prediabetes

Answer

Stress-induced hyperglycemia

Answer

Normal glucose tolerance

Answer

Diabetes mellitus

Question 2

Amyloid stroma is seen in which type of thyroid carcinoma?

Accepted Answer

Medullary carcinoma

Answer

Papillary carcinoma

Answer

Anaplastic carcinoma

Answer

Follicular carcinoma

Question 3

A 20-year-old woman and her twin sister both experience increasing diplopia. Their conditions develop within 3 years of each other. On physical examination, they have exophthalmos and weak extraocular muscle movement. The thyroid gland is diffusely enlarged but painless in each sister, and there is no lymphadenopathy in either woman. Which of the following serum laboratory findings is most likely to be reported in these sisters?

Accepted Answer

Decreased thyroid-stimulating hormone level

Answer

Decreased free thyroxine level

Answer

High titer thyroid peroxidase autoantibodies

Answer

Increased thyrotropin-releasing hormone level

Question 4

In the thyroid gland, the colloid material is predominantly composed of which of the following?

Accepted Answer

Thyroglobulin

Answer

Thyroxine

Answer

Monoiodotyrosine

Answer

Diiodotyrosine

Question 5

Amyloidosis is most commonly seen in which type of Diabetes Mellitus?

Accepted Answer

Type II diabetes mellitus

Answer

Maturity onset diabetes mellitus

Answer

Type I diabetes mellitus

Answer

Hypertension

Question 6

A 38-year-old woman undergoes a subtotal thyroidectomy. The biopsy specimen contains psammoma bodies and prominent papillae of epithelium with a fibrovascular core. The nuclear region of the cells shows groove formation, optical clearing, eosinophilic inclusions, and overlapping of nuclei. Which of the following is the most likely diagnosis?

Accepted Answer

Papillary thyroid carcinoma

Answer

Follicular thyroid carcinoma

Answer

Medullary thyroid carcinoma

Answer

Reidel's thyroiditis

Question 7

Which type of diabetes is associated with HLA?

Accepted Answer

Type I diabetes

Answer

Type II diabetes

Answer

Malnutrition-related diabetes

Answer

Gestational diabetes

Question 8

Acidophil stem cell tumors present with all of the following features except?

Accepted Answer

Thyrotoxicosis

Answer

Hypogonadism

Answer

Galactorrhea

Answer

Acromegaly

Question 9

Which of the following describes humoral hypercalcemia of malignancy (HHM)?

Accepted Answer

The rise in calcium levels due to parathyroid hormone-related peptide (PTH-rP)

Answer

Paraneoplastic calcitonin production

Answer

Vitamin D hypervitaminosis

Answer

Parafollicular C-cell proliferation of the thyroid gland

Question 10

All of the following are histological features of follicular carcinoma, except?

Accepted Answer

Intranuclear grooves and nuclear pseudo-inclusions

Answer

Capsular and vascular invasion

Answer

Uniform cells forming repetitive follicular pattern

Answer

Huhle cell variant present

Endocrine Pathology — MCQs

Endocrine Pathology — MCQs

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