Multiple endocrine neoplasia syndromes US Medical PG Practice Questions and MCQs
Practice US Medical PG questions for Multiple endocrine neoplasia syndromes. These multiple choice questions (MCQs) cover important concepts and help you prepare for your exams.
Multiple endocrine neoplasia syndromes US Medical PG Question 1: A 27-year-old man comes to the physician because of worsening abdominal pain over the last several months. He has also had recent feelings of sadness and a lack of motivation at work, where he is employed as a computer programmer. He denies suicidal thoughts. He has a history of multiple kidney stones. He has a family history of thyroid cancer in his father and uncle, who both underwent thyroidectomy before age 30. His temperature is 37°C (98°F), blood pressure is 138/86 mm Hg, and pulse is 87/min. Physical examination shows diffuse tenderness over the abdomen and obesity but is otherwise unremarkable. Serum studies show:
Na+ 141 mEq/L
K+ 3.6 mEq/L
Glucose 144 mg/dL
Ca2+ 12.1 mg/dL
Albumin 4.1 g/dL
PTH 226 pg/mL (normal range 12–88 pg/mL)
Results of a RET gene test return abnormal. The physician refers him to an endocrine surgeon. Which of the following is the most appropriate next step in diagnosis?
- A. Thyroidectomy
- B. Urine 5-HIAA
- C. Urine metanephrines (Correct Answer)
- D. Midnight salivary cortisol
- E. Serum gastrin
Multiple endocrine neoplasia syndromes Explanation: ***Urine metanephrines***
- The patient's presentation, including **abdominal pain**, **constipation** (implied by pain, mood changes, and high calcium), **hypertension**, **hypercalcemia** with **elevated PTH**, and a family history of **thyroid cancer** with an **abnormal RET gene test**, is highly suggestive of **MEN 2A** (Multiple Endocrine Neoplasia type 2A).
- **MEN 2A** is characterized by **medullary thyroid carcinoma** (MTC), **pheochromocytoma**, and **primary hyperparathyroidism**. Given the strong suspicion of MEN 2A and the presence of hypertension, screening for **pheochromocytoma** with **urine metanephrines** is crucial before any surgical intervention (e.g., thyroidectomy) due to the risk of a hypertensive crisis.
*Thyroidectomy*
- While a **thyroidectomy** is indicated for **medullary thyroid carcinoma** (strongly suggested by the family history of thyroid cancer and abnormal RET gene), it should **not be the immediate next step** before ruling out **pheochromocytoma**.
- Performing a thyroidectomy in a patient with an undiagnosed pheochromocytoma can lead to a **life-threatening hypertensive crisis** during surgery.
*Urine 5-HIAA*
- **Urine 5-HIAA** (5-hydroxyindoleacetic acid) is a test for **carcinoid syndrome**, which presents with flushing, diarrhea, and bronchospasm.
- These symptoms are **not consistent** with the patient's presentation, and carcinoid syndrome is **not a component of MEN 2A**.
*Midnight salivary cortisol*
- **Midnight salivary cortisol** is used to screen for **Cushing's syndrome**, which is characterized by symptoms such as central obesity, moon facies, striae, and muscle weakness.
- While the patient is obese, his other symptoms and laboratory findings are **not suggestive of Cushing's syndrome**, and it is not typically associated with MEN 2A.
*Serum gastrin*
- **Serum gastrin** levels are measured to diagnose **Zollinger-Ellison syndrome**, characterized by severe peptic ulcer disease and diarrhea due to a gastrinoma.
- While gastrinomas can occur in **MEN 1**, they are **not a feature of MEN 2A**, and the patient's symptoms are more consistent with other endocrine dysfunctions.
Multiple endocrine neoplasia syndromes US Medical PG Question 2: A 37-year-old woman comes to the physician for a 6-month history of headaches, anorexia, and vomiting. She has had a 10-kg (22-lb) weight loss during this period. She has type 1 diabetes mellitus for which she takes insulin. The patient's mother and sister have hypothyroidism. Her blood pressure is 80/60 mm Hg. Physical examination shows hyperpigmentation of the lips and oral mucosa. Serum studies show a parathyroid hormone level of 450 pg/mL and antibodies directed against 21-hydroxylase. Which of the following is the most likely diagnosis?
- A. Sheehan syndrome
- B. Multiple endocrine neoplasia type 2A
- C. Multiple endocrine neoplasia type 2B
- D. Autoimmune polyendocrine syndrome type 1
- E. Autoimmune polyendocrine syndrome type 2 (Correct Answer)
Multiple endocrine neoplasia syndromes Explanation: ***Autoimmune polyendocrine syndrome type 2***
- This patient presents with **Addison's disease** (hyperpigmentation, hypotension, weight loss, anorexia, vomiting), **Type 1 diabetes mellitus**, and likely **autoimmune thyroid disease** (family history of hypothyroidism). This classic triad is characteristic of autoimmune polyendocrine syndrome type 2 (Schmidt syndrome).
- The presence of **21-hydroxylase antibodies** confirms autoimmune adrenalitis, which is the primary cause of Addison's disease in APS Type 2. The elevated **parathyroid hormone** (PTH) level indicates **secondary hyperparathyroidism**, often a reactive response to vitamin D deficiency or chronic illness, not a primary component of this syndrome.
*Sheehan syndrome*
- This is a cause of **hypopituitarism** due to **postpartum hemorrhage** leading to ischemic necrosis of the pituitary gland.
- The patient's symptoms (hyperpigmentation, diabetes mellitus, 21-hydroxylase antibodies) do not align with the typical presentation or etiology of Sheehan syndrome. Additionally, Sheehan syndrome would present with **hypopigmentation** (due to decreased ACTH), not hyperpigmentation.
*Multiple endocrine neoplasia type 2A*
- This syndrome is characterized by **medullary thyroid carcinoma**, **pheochromocytoma**, and **primary hyperparathyroidism**.
- The patient's symptoms and laboratory findings (hyperpigmentation, T1DM, 21-hydroxylase antibodies) are not consistent with MEN 2A, which is a hereditary cancer syndrome, not an autoimmune disorder.
*Multiple endocrine neoplasia type 2B*
- This rare syndrome includes **medullary thyroid carcinoma**, **pheochromocytoma**, **mucosal neuromas**, and **marfanoid habitus**.
- This patient does not exhibit any of the hallmark features of MEN 2B.
*Autoimmune polyendocrine syndrome type 1*
- APS type 1 is characterized by a triad of **chronic mucocutaneous candidiasis**, **hypoparathyroidism**, and **Addison's disease**.
- While Addison's disease is present, the patient's other conditions (Type 1 diabetes, autoimmune thyroid disease) and the **elevated PTH** (rather than hypoparathyroidism) rule out APS type 1. APS-1 typically presents in childhood, while APS-2 presents in adulthood.
Multiple endocrine neoplasia syndromes US Medical PG Question 3: A 10-year-old boy is brought by his mother to his pediatrician for "skin growths." His mother reports that she started noticing small lumps arising from the patient's lips and eyelids several months ago. She also notes that he seems to suffer from frequent constipation and appears "weaker" than many of his peers. The boy's past medical history is unremarkable. His father and paternal grandmother have a history of medullary thyroid carcinoma. His height and weight are in the 85th and 45th percentiles, respectively. His temperature is 99°F (37.1°C), blood pressure is 110/65 mmHg, pulse is 90/min, and respirations are 18/min. On examination, he has an elongated face with protruding lips. There are numerous sessile painless nodules on the patient's lips, tongue, and eyelids. This patient's condition is most strongly associated with a mutation in which of the following genes?
- A. NF1
- B. MEN1
- C. RET (Correct Answer)
- D. NF2
- E. c-KIT
Multiple endocrine neoplasia syndromes Explanation: ***RET***
- The constellation of **skin growths** on the lips and eyelids (neuromas), **constipation** (ganglioneuromatosis), and a family history of **medullary thyroid carcinoma** (MTC) strongly suggests **Multiple Endocrine Neoplasia type 2B (MEN2B)**.
- MEN2B is caused by a germline mutation in the **RET proto-oncogene**, which is a receptor tyrosine kinase involved in cell growth and differentiation.
*NF1*
- Mutations in the **NF1 gene** cause **Neurofibromatosis type 1**, characterized by **café-au-lait spots**, neurofibromas (subcutaneous, not typically mucosal), iris Lisch nodules, and optic pathway gliomas.
- While it involves skin growths (neurofibromas), the specific mucosal neuromas, elongated facies, and family history of MTC are not typical features.
*MEN1*
- **MEN1 syndrome** is caused by mutations in the **MEN1 gene** and is associated with tumors of the **parathyroid**, **anterior pituitary**, and **pancreatic islet cells** (the 3 Ps).
- This patient's presentation of mucosal neuromas and medullary thyroid carcinoma is not characteristic of MEN1.
*NF2*
- Mutations in the **NF2 gene** cause **Neurofibromatosis type 2**, classically characterized by **bilateral vestibular schwannomas**, meningiomas, and ependymomas.
- Skin manifestations are less prominent and different from what is described, and MTC is not associated.
*c-KIT*
- Mutations in the **c-KIT gene** are primarily associated with **gastrointestinal stromal tumors (GIST)** and certain types of mastocytosis.
- It is not linked to the constellation of mucosal neuromas, elongated facies, or medullary thyroid carcinoma seen in this patient.
Multiple endocrine neoplasia syndromes US Medical PG Question 4: A 74-year-old retired female teacher is referred to the endocrinology clinic. She is very concerned about a large mass in her neck that has progressively enlarged over the past 2 weeks. She also reports a 15 pound weight loss over the last 3 months. She now has hoarseness and difficulty swallowing her food, giving her a sensation that food gets stuck in her windpipe when she swallows. There is no pain associated with swallowing. Her speech is monotonous. No other gait or language articulation problems are noted. Testing for cranial nerve lesions is unremarkable. On palpation, a large, fixed and non-tender mass in the thyroid is noted. Cervical lymph nodes are palpable bilaterally. The patient is urgently scheduled for an ultrasound-guided fine needle aspiration to guide management. Which of the following is the most likely gene mutation to be found in this mass?
- A. Activating mutation of the Ras protooncogene
- B. Inactivating mutation of the p53 tumor suppressor gene (Correct Answer)
- C. RET/PTC rearrangement
- D. BRAF mutation
- E. RET gene mutation
Multiple endocrine neoplasia syndromes Explanation: ***Inactivating mutation of the p53 tumor suppressor gene***
- The patient's presentation with a **rapidly enlarging, fixed, non-tender thyroid mass**, *hoarseness*, *dysphagia*, *weight loss*, and *palpable cervical lymph nodes* is highly suggestive of **anaplastic thyroid carcinoma (ATC)**, an aggressive malignancy.
- Inactivating mutations of the **p53 tumor suppressor gene** are frequently associated with the development and progression of ATC, contributing to its uncontrolled growth and poor prognosis.
*Activating mutation of the Ras protooncogene*
- **Ras mutations** are more commonly found in *follicular thyroid carcinoma* and *follicular variants of papillary thyroid carcinoma*.
- While they can indicate malignancy, they are not typically the primary genetic driver for the highly aggressive features seen in anaplastic carcinoma.
*RET/PTC rearrangement*
- **RET/PTC rearrangements** are characteristic genetic alterations found in **papillary thyroid carcinoma (PTC)**.
- PTC typically presents with a *slower growth rate* and *less aggressive features* compared to the rapid progression described in the patient.
*BRAF mutation*
- The **BRAF V600E mutation** is the most common genetic alteration in **papillary thyroid carcinoma (PTC)**, especially the conventional and tall-cell variants.
- While it indicates a more aggressive subset of PTC, it is generally not the primary mutation associated with the extremely aggressive and rapidly progressing features of anaplastic thyroid carcinoma.
*RET gene mutation*
- **Germline RET mutations** are primarily associated with **medullary thyroid carcinoma (MTC)**, often occurring as part of Multiple Endocrine Neoplasia type 2 (MEN2).
- The clinical presentation with a *rapidly growing, fixed mass* and *compressive symptoms* is less typical for MTC, which can also be aggressive but usually presents differently.
Multiple endocrine neoplasia syndromes US Medical PG Question 5: A 45-year-old woman comes to see you for a second opinion regarding an upcoming surgery for pancreatic insulinoma. While taking a surgical history, she tells you she previously had a pituitary tumor resected. For which additional neoplasms might you consider testing her?
- A. Parathyroid adenoma (Correct Answer)
- B. Medullary thyroid carcinoma
- C. Mucosal neuroma
- D. Multiple myeloma
- E. Pheochromocytoma
Multiple endocrine neoplasia syndromes Explanation: ***Parathyroid adenoma***
- The patient's history of a **pituitary tumor** and a **pancreatic insulinoma** strongly suggests **Multiple Endocrine Neoplasia Type 1 (MEN1)**.
- **Parathyroid adenomas** are the most common manifestation of MEN1, affecting over 90% of patients, and should be screened for.
*Medullary thyroid carcinoma*
- This is a characteristic component of **Multiple Endocrine Neoplasia Type 2 (MEN2)**.
- MEN2 includes medullary thyroid carcinoma, pheochromocytoma, and parathyroid hyperplasia, which is distinct from the patient's presentation.
*Mucosal neuroma*
- **Mucosal neuromas** are associated with **Multiple Endocrine Neoplasia Type 2B (MEN2B)**, a subtype of MEN2.
- MEN2B also typically involves medullary thyroid carcinoma and pheochromocytoma, which do not align with the patient's current tumors.
*Multiple myeloma*
- This is a **hematologic malignancy** involving plasma cells and is not typically associated with the type of endocrine tumors seen in this patient.
- There is no direct link between multiple myeloma and pituitary or pancreatic neuroendocrine tumors.
*Pheochromocytoma*
- **Pheochromocytoma** is a tumor of the adrenal medulla and is a hallmark of **Multiple Endocrine Neoplasia Type 2 (MEN2)**.
- While it is an endocrine tumor, it is not part of the triad seen in MEN1 (pituitary, parathyroid, and pancreatic tumors).
Multiple endocrine neoplasia syndromes US Medical PG Question 6: A 27-year-old man comes to the physician because of a 4-month history of recurrent episodes of headaches, palpitations, and sweating. He was adopted shortly after birth and does not know his biological parents. His pulse is 103/min and blood pressure is 160/105 mm Hg. Physical examination shows multiple soft, yellow papules on the tip of the tongue. There is a 2-cm, firm thyroid nodule. He has long and slender upper extremities, and his elbows and knees can be hyperextended. The most likely cause of this patient's condition is a mutation in which of the following genes?
- A. TSC2
- B. COL5A1
- C. RET (Correct Answer)
- D. MEN1
- E. FBN1
Multiple endocrine neoplasia syndromes Explanation: ***Correct Option: RET***
- The patient's symptoms (headaches, palpitations, sweating, hypertension) point to a **pheochromocytoma**, and the thyroid nodule suggests **medullary thyroid carcinoma**. The marfanoid habitus (long, slender extremities, hyperextension) and mucosal neuromas (yellow papules on the tongue) are characteristic features of **Multiple Endocrine Neoplasia type 2B (MEN2B)**.
- **MEN2B** is caused by a germline gain-of-function mutation in the **RET proto-oncogene**, which is involved in cell growth and differentiation.
*Incorrect Option: TSC2*
- Mutations in **TSC2** are associated with **tuberous sclerosis complex**, a neurocutaneous disorder characterized by **facial angiofibromas**, ash-leaf spots, shagreen patches, renal angiomyolipomas, and brain tubers.
- The patient's presentation with pheochromocytoma, medullary thyroid cancer, and marfanoid features is not consistent with tuberous sclerosis.
*Incorrect Option: COL5A1*
- Mutations in **COL5A1** are associated with **Ehlers-Danlos syndrome (classical type)**, which is characterized by **skin hyperextensibility**, joint hypermobility, and tissue fragility.
- While the patient exhibits joint hypermobility, the constellation of pheochromocytoma, medullary thyroid carcinoma, and mucosal neuromas is not a typical feature of Ehlers-Danlos syndrome.
*Incorrect Option: MEN1*
- Mutations in the **MEN1 gene** cause **Multiple Endocrine Neoplasia type 1 (MEN1)**, characterized by tumors of the **parathyroid glands** (leading to hyperparathyroidism), **pituitary gland**, and **pancreatic islet cells**.
- The patient's presentation with medullary thyroid carcinoma and pheochromocytoma, along with mucosal neuromas and marfanoid features, is not consistent with MEN1.
*Incorrect Option: FBN1*
- Mutations in the **FBN1 gene** cause **Marfan syndrome**, characterized by **aortic root dilation**, ectopia lentis, and marfanoid body habitus (long limbs, joint hypermobility).
- While the patient has a marfanoid habitus, the presence of pheochromocytoma, medullary thyroid carcinoma, and mucosal neuromas are not features of Marfan syndrome, differentiating it from MEN2B.
Multiple endocrine neoplasia syndromes US Medical PG Question 7: A 38-year-old female presents to her primary care physician with complaints of several episodes of palpitations accompanied by panic attacks over the last month. She also is concerned about many instances over the past few weeks where food has been getting stuck in her throat and she has had trouble swallowing. She denies any prior medical problems and reports a family history of cancer in her mother and maternal grandfather but cannot recall any details regarding the type of cancer(s) or age of diagnosis. Her vital signs at today's visit are as follows: T 37.6 deg C, HR 106, BP 158/104, RR 16, SpO2 97%. Physical examination is significant for a nodule on the anterior portion of the neck that moves with swallowing, accompanied by mild lymphadenopathy. A preliminary work-up is initiated, which shows hypercalcemia, elevated baseline calcitonin, and an inappropriately elevated PTH level. Diagnostic imaging shows bilateral adrenal lesions on an MRI of the abdomen/pelvis. Which of the following is the most likely diagnosis in this patient?
- A. Familial medullary thyroid cancer (FMTC)
- B. Li-Fraumeni syndrome
- C. Multiple endocrine neoplasia (MEN) IIa (Correct Answer)
- D. Multiple endocrine neoplasia (MEN) I
- E. Multiple endocrine neoplasia (MEN) IIb
Multiple endocrine neoplasia syndromes Explanation: ***Multiple endocrine neoplasia (MEN) IIa***
- This patient presents with **medullary thyroid cancer** (due to the thyroid nodule, elevated calcitonin, and family history of cancer), **pheochromocytoma** (indicated by palpitations, panic attacks, hypertension, and adrenal lesions), and **primary hyperparathyroidism** (evidenced by hypercalcemia and inappropriately elevated PTH). These three conditions are the classic triad of MEN IIa.
- The symptoms of food getting stuck in her throat are also consistent with the presence of a **thyroid nodule**.
*Familial medullary thyroid cancer (FMTC)*
- While the patient has **medullary thyroid cancer**, FMTC is typically characterized solely by medullary thyroid carcinoma without the associated pheochromocytoma or primary hyperparathyroidism seen in this case.
- This patient's presentation includes **adrenal lesions** and **hyperparathyroidism**, which are not features of isolated FMTC.
*Li-Fraumeni syndrome*
- This syndrome is associated with a high risk of various cancers, including sarcomas, breast cancer, brain tumors, and adrenocortical carcinoma, but it is not typically associated with **medullary thyroid cancer, pheochromocytoma, or primary hyperparathyroidism** as a primary presentation.
- The genetic basis is a mutation in the **TP53 gene**, and the clinical picture does not match the specific endocrine tumors observed here.
*Multiple endocrine neoplasia (MEN) I*
- MEN I is characterized by tumors of the **parathyroid, pituitary, and pancreas** (the 3 Ps).
- This patient's presentation of medullary thyroid cancer, pheochromocytoma, and primary hyperparathyroidism does not include pituitary or pancreatic tumors, and medullary thyroid cancer and pheochromocytoma are not part of the MEN I spectrum.
*Multiple endocrine neoplasia (MEN) IIb*
- MEN IIb includes **medullary thyroid cancer** and **pheochromocytoma**, which are present in this patient.
- However, MEN IIb also classically presents with characteristic **mucosal neuromas** and a **marfanoid habitus**, and *lacks* primary hyperparathyroidism, which this patient clearly exhibits.
Multiple endocrine neoplasia syndromes US Medical PG Question 8: A 10-year-old girl is brought to the physician by her parents due to 2 months of a progressively worsening headache. The headaches were initially infrequent and her parents attributed them to stress from a recent move. However, over the last week the headaches have gotten significantly worse and she had one episode of vomiting this morning when she woke up. Her medical history is remarkable for a hospitalization during infancy for bacterial meningitis. On physical exam, the patient has difficulty looking up. The lower portion of her pupil is covered by the lower eyelid and there is sclera visible below the upper eyelid. A magnetic resonance imaging (MRI) of the brain is shown. Which of the following is the most likely diagnosis?
- A. Ependymoma
- B. Medulloblastoma
- C. Craniopharyngioma
- D. Pinealoma (Correct Answer)
- E. Pituitary Adenoma
Multiple endocrine neoplasia syndromes Explanation: ***Pinealoma***
- The constellation of a progressively worsening headache, vomiting, and difficulty looking up (Parinaud's syndrome or **dorsal midbrain syndrome**) with **hydrocephalus** visible on MRI points strongly to a **pineal region tumor** that compresses the **tectal plate** and obstructs CSF flow. The visible sclera below the upper eyelid is due to **retraction of the upper eyelids**, a component of Parinaud's syndrome.
- The MRI shows significant **ventricular dilation**, particularly of the lateral and third ventricles, indicating **obstructive hydrocephalus**, which is consistent with a mass in the pineal region compressing the **cerebral aqueduct**.
*Ependymoma*
- Ependymomas most commonly occur in the **fourth ventricle** in children and can cause hydrocephalus by obstructing CSF flow at that level.
- However, typical symptoms would be more associated with **cerebellar dysfunction** (ataxia, nystagmus), and Parinaud's syndrome is not characteristic.
*Medulloblastoma*
- Medulloblastomas are highly malignant **cerebellar tumors** in children, typically arising from the vermis, and often cause **ataxia**, truncal instability, and hydrocephalus due to fourth ventricle obstruction.
- While they cause hydrocephalus and headaches, they do not typically present with Parinaud's syndrome.
*Craniopharyngioma*
- Craniopharyngiomas are **suprasellar tumors** that originate from Rathke's pouch remnants and can cause headaches, visual field defects (**bitemporal hemianopsia**), and **endocrine dysfunction** (e.g., growth delays, diabetes insipidus).
- They are typically located anteriorly, compressing the **optic chiasm** and hypothalamus, not directly obstructing the cerebral aqueduct to cause Parinaud's syndrome.
*Pituitary Adenoma*
- Pituitary adenomas are rare in children and typically cause symptoms related to **hormonal overproduction** or compression of adjacent structures, such as **visual field defects** (bitemporal hemianopsia).
- While large adenomas can cause headaches, they are not typically associated with **Parinaud's syndrome** or rapid-onset **obstructive hydrocephalus** in this manner.
Multiple endocrine neoplasia syndromes US Medical PG Question 9: A 40-year-old man presents with a painless firm mass in the right breast. Examination shows retraction of the nipple and the skin is fixed to the underlying mass. The axillary nodes are palpable. Which of the following statements is FALSE regarding the above condition?
- A. Lobular cancer is the most common breast cancer in males (Correct Answer)
- B. BRCA2 mutations are associated with increased risk
- C. These are positive for estrogen receptor
- D. Endocrine therapy plays an important role in treatment
- E. Gynecomastia may be caused by certain medications
Multiple endocrine neoplasia syndromes Explanation: ***Lobular cancer is the most common breast cancer in males***
- This statement is **FALSE** and is the correct answer. The most common type of breast cancer in males is **invasive ductal carcinoma (IDC)**, accounting for about 80-90% of cases.
- **Invasive lobular carcinoma** is rare in men because men have very few lobules in their breast tissue.
*Gynecomastia may be caused by certain medications*
- This statement is **TRUE**. Medications such as spironolactone, cimetidine, finasteride, antipsychotics, and anabolic steroids can cause gynecomastia.
- However, the clinical presentation described (firm mass, nipple retraction, skin fixation, axillary nodes) is consistent with **malignancy**, not gynecomastia.
*BRCA2 mutations are associated with increased risk*
- This statement is **TRUE**. Male breast cancer is strongly associated with **BRCA2 mutations** (and less commonly BRCA1), which are hereditary.
- Men with BRCA2 mutations have a 5-10% lifetime risk of developing breast cancer, compared to less than 0.1% in the general male population.
*These are positive for estrogen receptor*
- This statement is **TRUE**. A vast majority (over 90%) of male breast cancers are **estrogen receptor (ER) positive**, which makes them responsive to endocrine therapy.
- This high rate of ER positivity is even greater than in female breast cancers.
*Endocrine therapy plays an important role in treatment*
- This statement is **TRUE**. Given the high prevalence of ER positivity (over 90%), endocrine therapy such as **tamoxifen** or aromatase inhibitors is a cornerstone of treatment for male breast cancer.
- Endocrine therapy is used in both adjuvant and metastatic settings for hormone receptor-positive disease.
Multiple endocrine neoplasia syndromes US Medical PG Question 10: A 4-month-old boy with a history of multiple infections presents with muscle stiffness. On physical exam, he is found to have carpopedal spasm as well as a heart murmur. Based on your clinical suspicion you decide to obtain a chest X-ray which shows a diminished shadow in the mediastinum. A mutation in which of the following chromosomes is the most likely cause of this patient's presentation?
- A. Chromosome 22 (Correct Answer)
- B. Chromosome 17
- C. Chromosome 5
- D. Chromosome 7
- E. Chromosome X
Multiple endocrine neoplasia syndromes Explanation: ***Chromosome 22***
- This patient's presentation with **multiple infections**, **muscle stiffness** (indicating hypocalcemia), **carpopedal spasm**, a **heart murmur**, and a **diminished thymic shadow** on chest X-ray are classic signs of **DiGeorge syndrome**.
- **DiGeorge syndrome** is caused by a microdeletion on **chromosome 22q11**, leading to abnormal development of the third and fourth pharyngeal pouches.
*Chromosome 17*
- Deletions or duplications on chromosome 17 are associated with conditions such as **Charcot-Marie-Tooth disease type 1A** or **Smith-Magenis syndrome**, which do not typically present with this constellation of symptoms.
- While these disorders involve developmental issues, they do not specifically cause thymic aplasia or congenital heart defects characteristic of DiGeorge syndrome.
*Chromosome 5*
- Deletions on chromosome 5 can lead to **Cri-du-chat syndrome**, characterized by a cat-like cry, intellectual disability, and microcephaly.
- This syndrome does not involve the characteristic immune deficiency or hypocalcemia seen in DiGeorge syndrome.
*Chromosome 7*
- Disorders associated with chromosome 7 include **Williams syndrome** (deletion on 7q11.23) and some forms of cystic fibrosis (due to mutations in the CFTR gene on 7q31.2).
- **Williams syndrome** presents with distinct facial features, cardiovascular problems (supravalvular aortic stenosis), and intellectual disability, but not thymic aplasia or hypocalcemia.
*Chromosome X*
- Chromosome X abnormalities are linked to conditions like **Turner syndrome** (XO) or **Klinefelter syndrome** (XXY), which primarily affect sex development and reproduction.
- While X-linked disorders can cause various health issues, they do not typically manifest with the specific combination of thymic hypoplasia, hypocalcemia, and congenital heart defects indicative of DiGeorge syndrome.
More Multiple endocrine neoplasia syndromes US Medical PG questions available in the OnCourse app. Practice MCQs, flashcards, and get detailed explanations.
