Multiple Endocrine Neoplasia Syndromes — MCQs
Which of the following syndromes is least likely to be associated with obesity?
Which type of thyroid cancer is associated with primary hyperparathyroidism and phaeochromocytoma?
Colonoscopy is not indicated in which of the following conditions?
Submucosal neuroma is associated with
Which PCR technique is best suited for identifying a syndrome with multiple causative agents?
Hypocalcemia in a child may be associated with
An eight-year-old girl presented by her mother with sexual precocity. She may have the following disorder:
Congenital adrenal hyperplasia most commonly presents as
A child with decreased levels of LH, FSH and Testosterone presents with delayed puberty. Which of the following is the most likely Diagnosis
Causes of Hypocalcemia in a child are
Multiple Endocrine Neoplasia Syndromes Indian Medical PG Practice Questions and MCQs
Question 1: Which of the following syndromes is least likely to be associated with obesity?
- A. Cushing syndrome
- B. Prader willi syndrome
- C. Sipple syndrome (Correct Answer)
- D. Pickwickian syndrome
Explanation: ***Sipple syndrome*** - Sipple syndrome, also known as **multiple endocrine neoplasia type 2**, is primarily associated with **medullary thyroid carcinoma** and does not typically correlate with obesity. - It includes signs like **pheochromocytoma** and **hyperparathyroidism**, but obesity is not a prominent feature. *Cushing syndrome* - Cushing syndrome leads to **excess cortisol**, commonly resulting in weight gain and central obesity [1]. - Characteristic features include **moon facies**, **buffalo hump**, and easy bruising, all associated with obesity [1]. *Pickwinian syndrome* - Pickwinian syndrome, characterized by **severe obesity**, is a condition primarily affecting physical stature and weight. - It is linked to **hypoventilation** and sleep apnea, reinforcing the presence of obesity. *Prader willi syndrome* - Prader-Willi syndrome is marked by **insatiable hunger** leading to **obesity** due to hypothalamic dysfunction [2]. - Individuals with this condition also demonstrate **hypotonia** and developmental delays, commonly accompanied by obesity [2]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Endocrine System, pp. 1127-1129. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Central Nervous System Synapse, pp. 454-455.
Question 2: Which type of thyroid cancer is associated with primary hyperparathyroidism and phaeochromocytoma?
- A. Medullary carcinoma of the thyroid (Correct Answer)
- B. Papillary carcinoma of the thyroid
- C. Anaplastic carcinoma of the thyroid
- D. Follicular carcinoma of the thyroid
Explanation: ***Medullary carcinoma of the thyroid*** - Associated with **multiple endocrine neoplasia (MEN) syndrome type 2**, which includes primary hyperparathyroidism and phaeochromocytoma [1]. - Medullary carcinoma arises from **C cells** (parafollicular cells) and is linked with **elevated calcitonin** levels. *Papillary carcinoma of the thyroid* - The most common type of thyroid cancer, but **not associated** with MEN syndromes. - Typically presents as a solitary **nodule** and is linked with **radiation exposure** rather than endocrine syndromes. *Anaplastic carcinoma of the thyroid* - A highly aggressive and undifferentiated form of thyroid cancer, often associated with **poor prognosis**. - Usually arises in older adults and does not have associations with **hyperparathyroidism** or phaeochromocytoma. *Follicular carcinoma of the thyroid* - Characterized by **thyroid follicle formation** and can be associated with **iodine deficiency**, but not with MEN syndromes. - It usually presents as a **solitary thyroid nodule** and lacks connection with **primary hyperparathyroidism**.
Question 3: Colonoscopy is not indicated in which of the following conditions?
- A. Familial Adenomatous Polyposis
- B. Multiple Endocrine Neoplasia type 2B (Correct Answer)
- C. Hereditary Nonpolyposis Colorectal Cancer
- D. Peutz-Jeghers Syndrome
Explanation: ***Multiple Endocrine Neoplasia type 2B*** - **MEN 2B** is characterized by **medullary thyroid carcinoma**, **pheochromocytoma**, and specific features such as **mucosal neuromas** and a marfanoid habitus, but it does **not involve colonic polyps or an increased risk of colorectal cancer** that would necessitate colonoscopy. - While gastrointestinal manifestations like ganglioneuromatosis may be present, **routine colonoscopy screening** is not indicated in this syndrome as there is no increased colorectal cancer risk. *Familial Adenomatous Polyposis* - **FAP** is an autosomal dominant disorder characterized by the development of hundreds to thousands of **colorectal adenomatous polyps**, which have an almost 100% risk of progressing to **colorectal cancer** if untreated. - **Regular colonoscopic surveillance** and eventual colectomy are essential for managing this condition due to the high malignancy risk. *Hereditary Nonpolyposis Colorectal Cancer* - Also known as **Lynch syndrome**, HNPCC is characterized by an increased risk of **colorectal cancer** and other extra-colonic cancers (e.g., endometrial, ovarian) due to germline mutations in **mismatch repair genes**. - **Colonoscopy is crucial** for early detection and prevention of colorectal cancer in affected individuals, typically starting at age 20-25 years or 2-5 years before the youngest family member was diagnosed. *Peutz-Jeghers Syndrome* - **Peutz-Jeghers Syndrome** is an autosomal dominant condition characterized by **hamartomatous polyps** throughout the gastrointestinal tract and mucocutaneous pigmentation (melanotic macules on lips, oral mucosa, and digits). - These polyps have **malignant potential** with increased risk of gastrointestinal and extra-intestinal cancers (breast, ovarian, pancreatic). - **Regular colonoscopic surveillance** is recommended starting from late teens or early 20s for polyp detection and removal.
Question 4: Submucosal neuroma is associated with
- A. MEN 2 A
- B. MEN 2B (Correct Answer)
- C. MEN 1
- D. None of the options
Explanation: ***MEN 2B (Multiple Endocrine Neoplasia Type 2B)*** - **Submucosal neuromas** are a distinctive feature of MEN 2B, specifically noticeble as mucosal neuromas on the lips, tongue, and gastrointestinal tract. - This syndrome is characterized by the presence of **medullary thyroid carcinoma**, **pheochromocytoma**, and mucocutaneous neuromas, without hyperparathyroidism. *MEN 2A (Multiple Endocrine Neoplasia Type 2A)* - MEN 2A is characterized by **medullary thyroid carcinoma**, **pheochromocytoma**, and **primary hyperparathyroidism**. - It does not typically feature extensive **submucosal neuromas** as a primary diagnostic criterion. *MEN 1 (Multiple Endocrine Neoplasia Type 1)* - MEN 1 involves tumors of the **parathyroid glands**, **anterior pituitary**, and **pancreatic islet cells** (the '3 Ps'). - **Submucosal neuromas** are not a component of the MEN 1 syndrome. *None of the options* - This option is incorrect because **submucosal neuromas** are a characteristic finding in MEN 2B.
Question 5: Which PCR technique is best suited for identifying a syndrome with multiple causative agents?
- A. RT-PCR
- B. Multiplex PCR (Correct Answer)
- C. Nested PCR
- D. Conventional PCR
Explanation: ***Multiplex PCR*** - **Multiplex PCR** allows for the simultaneous amplification of **multiple DNA targets** in a single reaction, making it ideal for identifying syndromes with numerous potential causative agents. - This method uses **multiple primer pairs** in one reaction tube, each designed to amplify a specific target sequence, thus efficiently detecting various pathogens or genetic markers. *RT-PCR* - **Reverse Transcription PCR (RT-PCR)** is used to detect **RNA targets** by first converting RNA into cDNA, which is then amplified. - While useful for RNA viruses or gene expression studies, it is not primarily designed for simultaneous detection of multiple diverse causative agents in the same way as multiplex PCR. *Nested PCR* - **Nested PCR** uses two sets of primers in sequential reactions to **increase sensitivity and specificity** by reducing non-specific binding. - This technique is generally employed to detect very low copies of a specific target or to overcome issues with non-specific amplification, rather than for identifying multiple different agents concurrently. *Conventional PCR* - **Conventional PCR** amplifies a **single specific DNA target** using one pair of primers per reaction. [1] - It requires separate reactions for each potential causative agent, making it inefficient and labor-intensive when testing for a syndrome with multiple etiologies. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. (Basic Pathology) introduces the student to key general principles of pathology, both as a medical science and as a clinical activity with a vital role in patient care. Part 2 (Disease Mechanisms) provides fundamental knowledge about the cellular and molecular processes involved in diseases, providing the rationale for their treatment. Part 3 (Systematic Pathology) deals in detail with specific diseases, with emphasis on the clinically important aspects., pp. 56-57.
Question 6: Hypocalcemia in a child may be associated with
- A. DiGeorge syndrome
- B. Magnesium deficiency
- C. Hypoparathyroidism
- D. All of the options (Correct Answer)
Explanation: ***All of the options*** - **Hypocalcemia** can stem from various causes, and all the listed conditions (DiGeorge syndrome, magnesium deficiency, and hypoparathyroidism) are known to cause it. - A comprehensive understanding of potential etiologies is crucial for accurate diagnosis and treatment of hypocalcemia in children. *Digeorge syndrome* - **DiGeorge syndrome** is a genetic disorder associated with abnormal development of the **thymus** and **parathyroid glands**, leading to **hypoparathyroidism** and subsequent hypocalcemia. - This condition is characterized by a deletion on **chromosome 22q11.2**, resulting in various clinical manifestations including **cardiac defects** and **immune deficiencies**. *Magnesium deficiency* - **Magnesium deficiency (hypomagnesemia)** can impair the release of **parathyroid hormone (PTH)** and reduce target organ responsiveness to PTH, leading to **hypocalcemia**. - Adequate magnesium levels are essential for the proper functioning of the **parathyroid glands** and calcium homeostasis. *Hypoparathyroidism* - **Hypoparathyroidism** is a condition where the **parathyroid glands** produce insufficient amounts of **parathyroid hormone (PTH)**, which is crucial for regulating calcium levels. - Insufficient PTH leads to decreased reabsorption of calcium in the kidneys and reduced calcium release from bones, resulting in **hypocalcemia**.
Question 7: An eight-year-old girl presented by her mother with sexual precocity. She may have the following disorder:
- A. Addison's disease
- B. Neuroblastoma
- C. Hyperthyroidism
- D. McCune Albright syndrome (Correct Answer)
Explanation: ***McCune Albright syndrome*** - This syndrome is characterized by a triad of **fibrous dysplasia**, **café-au-lait spots**, and **precocious puberty**, which fits the clinical picture of an 8-year-old girl with sexual precocity. - The precocious puberty in McCune-Albright syndrome is typically **gonadotropin-independent**, meaning it originates from the ovaries due to overactivity rather than pituitary stimulation. *Addison's disease* - Addison's disease involves **adrenal insufficiency**, leading to symptoms like fatigue, weight loss, and hyperpigmentation, but it typically does not cause sexual precocity. - It would be associated with low **cortisol** and high **ACTH** levels, which are not indicative of premature sexual development. *Neuroblastoma* - **Neuroblastoma** is a childhood cancer that can cause symptoms due to catecholamine secretion or mass effect, but it does not directly cause sexual precocity. - While it can be associated with paraneoplastic syndromes, precocious puberty is not a typical manifestation. *Hyperthyroidism* - **Hyperthyroidism** in children can present with symptoms like weight loss, tachycardia, and goiter, but it is not a direct cause of sexual precocity. - While thyroid hormones influence growth and development, they do not typically trigger premature pubertal changes.
Question 8: Congenital adrenal hyperplasia most commonly presents as
- A. 46,XY DSD
- B. Ovotesticular DSD
- C. 46,XX DSD with virilization (Correct Answer)
- D. 46,XY DSD with undervirilization
Explanation: ***46,XX DSD with virilization*** (formerly female pseudohermaphroditism) - This is the **most common presentation** of congenital adrenal hyperplasia (CAH), particularly due to **21-hydroxylase deficiency**, which accounts for >90% of CAH cases. - Affects genetically female (46,XX) individuals with excess **androgens** produced by hyperplastic adrenal glands leading to **virilization** of external genitalia. - Clinical features include **clitoromegaly, labioscrotal fusion**, and varying degrees of masculinization, while **internal female organs (uterus, ovaries, fallopian tubes) remain normal**. - This is the classic presentation that brings CAH to clinical attention in newborn screening programs. *46,XY DSD* (formerly 46,XY intersex) - This terminology refers to conditions where genetically male individuals (46,XY) have atypical genital development. - Common causes include **androgen insensitivity syndrome** or disorders of testosterone synthesis (5α-reductase deficiency, 17β-hydroxysteroid dehydrogenase deficiency). - CAH in 46,XY individuals typically presents with **isosexual precocious pseudopuberty** (early virilization) in simple virilizing forms or **salt-wasting adrenal crisis** in severe forms, not undervirilization. *Ovotesticular DSD* (formerly true hermaphroditism) - Very rare condition where an individual has **both ovarian and testicular tissue**, either as separate gonads or combined as ovotestes. - Often involves complex chromosomal patterns including **46,XX/46,XY mosaicism** or 46,XX with SRY translocation. - Not related to CAH pathophysiology, which involves enzymatic defects in steroidogenesis. *46,XY DSD with undervirilization* (formerly male pseudohermaphroditism) - Occurs when 46,XY individuals have **undervirilized or ambiguous external genitalia** due to impaired androgen synthesis or action. - Causes include disorders of testicular development, androgen biosynthesis defects, or **androgen insensitivity**. - While CAH can affect males, it causes **excess androgens** leading to precocious puberty, not undervirilization.
Question 9: A child with decreased levels of LH, FSH and Testosterone presents with delayed puberty. Which of the following is the most likely Diagnosis
- A. Klinefelter's syndrome
- B. Kallman's syndrome (Correct Answer)
- C. Testicular infection
- D. Androgen Insensitivity Syndrome
Explanation: ***Kallman's syndrome*** - **Kallmann's syndrome** is characterized by **isolated hypogonadotropic hypogonadism**, meaning the hypothalamus fails to produce **GnRH**, leading to low LH and FSH, and consequently low testosterone, causing delayed puberty. - A key distinguishing feature is the association with **anosmia or hyposmia** (impaired sense of smell) due to abnormal migration of olfactory neurons and GnRH-producing neurons. *Klinefelter's syndrome* - This condition is characterized by **primary hypogonadism** (testicular failure) due to an extra X chromosome (47,XXY), leading to **high LH and FSH** in an attempt to stimulate the failing testes. - Although testosterone is low and puberty is delayed, the **elevated gonadotropins** differentiate it from Kallmann's syndrome. *Testicular infection* - An infection like **orchitis** can lead to testicular damage and *primary hypogonadism*, resulting in low testosterone. - However, similar to Klinefelter's, this would typically cause **elevated LH and FSH** due to the lack of negative feedback from the testes. *Androgen Insensitive syndrome* - In **Androgen Insensitivity Syndrome (AIS)**, testosterone levels are typically **normal or even elevated**, but the body's cells are unable to respond to androgens due to defective receptors. - This condition presents with a female phenotype despite a 46,XY karyotype, and **gonadotropin levels (LH and FSH) are usually normal to high**, not decreased.
Question 10: Causes of Hypocalcemia in a child are
- A. Hypoparathyroidism
- B. DiGeorge syndrome
- C. Magnesium deficiency
- D. All of the options (Correct Answer)
Explanation: ***All of the options*** - **Hypoparathyroidism**, **DiGeorge syndrome**, and **Magnesium deficiency** are all well-established causes of hypocalcemia in children. - Each condition interferes with calcium regulation through distinct mechanisms, leading to low calcium levels. *Hypoparathyroidism* - This condition involves insufficient production of **parathyroid hormone (PTH)**, which is crucial for maintaining calcium levels. - Without adequate PTH, the body cannot reabsorb calcium from the kidneys or release it from bone effectively, leading to **hypocalcemia**. *DiGeorge syndrome* - This is a genetic disorder characterized by the **maldevelopment of the parathyroid glands** (among other issues), resulting in congenital hypoparathyroidism. - The absence or underdevelopment of these glands leads to **low PTH levels** and, consequently, hypocalcemia shortly after birth. *Magnesium deficiency* - **Magnesium is essential for normal PTH secretion** and for the target tissues' response to PTH. - When magnesium levels are too low, PTH synthesis and release are impaired, and the body's response to any available PTH is diminished, causing **functional hypoparathyroidism** and hypocalcemia.
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