An otherwise healthy 18-year-old female is diagnosed with high-risk neuroblastoma after presenting with fatigue and bony pain. Imaging findings demonstrate a left adrenal mass with multiple osseous metastases. She successfully completes standard therapy for high-risk neuroblastoma, but experiences several episodes of disease recurrence and ultimately dies of her disease 10 years after her initial diagnosis. During her treatment, her tumor was sent for molecular analysis. Of the following, what molecular aberration was most likely to have been detected?

Correct Answer: C

Rationale: The correct answer is C: ATRX mutation. In neuroblastoma, ATRX mutations are associated with poor prognosis and high-risk disease. ATRX gene mutations are commonly found in cases with aggressive behavior and poor outcomes, such as in this case where the patient experienced disease recurrence and ultimately died. ATRX mutations are linked to chromosomal instability and telomere dysfunction, which can contribute to tumor progression and resistance to therapy. A: ETV6-NTRK3 gene fusion is more commonly associated with infantile fibrosarcoma and secretory breast carcinoma, not neuroblastoma. B: PTPN11 mutations are typically seen in juvenile myelomonocytic leukemia and Noonan syndrome, not neuroblastoma. D: WT1 mutations are more commonly found in Wilms tumor and acute myeloid leukemia, not neuroblastoma. In summary, the ATRX mutation is the most likely molecular aberration detected in this patient with high-risk neuroblast

Correct Answer: D

Rationale: Thrombomodulin alters thrombin's function by binding to it and activating protein C. Activated protein C then inhibits factors Va and VIIIa, which are essential for the formation of fibrinogen. Protein C (choice A) also inhibits coagulation, but it doesn't directly alter thrombin's function. Protein S (choice B) enhances protein C's activity but doesn't directly affect thrombin. Antithrombin (choice C) inhibits thrombin and other coagulation factors, but it doesn't specifically alter thrombin's function to downregulate fibrinogen formation.

Correct Answer: B

Rationale: Step-by-step rationale for why answer B is correct: 1. Autoimmune thrombocytopenia is a condition where the body's immune system attacks and destroys its own platelets. 2. Platelet transfusions in patients with autoimmune thrombocytopenia are less likely to be successful due to the underlying immune response. 3. Reviewing transfusion records of subjects with this condition would likely show a pattern of unsuccessful platelet transfusions. 4. This conclusion is supported by medical knowledge and understanding of autoimmune thrombocytopenia. Summary: - Choice A is incorrect because frozen storage of platelets does not necessarily increase units available in the context of the study. - Choice C is incorrect as platelet units can carry a risk of transmission for hepatitis C infection. - Choice D is incorrect as the preference for pooled donor platelets over single-donor platelets is not a conclusion that can be drawn from the study.

Correct Answer: D

Rationale: Ferroportin is a transmembrane iron exporter responsible for releasing iron from cells into the bloodstream. It is crucial in regulating systemic iron levels. Choice A is incorrect as storage iron is typically stored as ferritin. Choice B is incorrect as ferroportin is not found in the plasma but on cell membranes. Choice C is incorrect as erythroid progenitors do not directly interact with ferroportin. Therefore, the correct answer is D as it accurately describes the function of ferroportin in iron metabolism.

Correct Answer: A

Rationale: The correct answer is A: Extremity. Rhabdomyosarcoma has a better prognosis when located in the extremities compared to other sites due to easier surgical resection and less risk of metastasis. Prostate (B) is less common in children and has a poorer prognosis. Infratemporal fossa (C) and neck (D) sites have a higher risk of local invasion and metastasis, leading to a worse prognosis compared to extremity sites.