A 9-month-old boy has been referred to you for the evaluation of an enlarged abdomen. Imaging studies show a large liver mass (PRETEXT III). Alfa-fetoprotein is 98 ng/mL, and a CT scan of the lungs show bilateral lung metastases. A needle biopsy is performed, and you are planning to review the specimen with the pathologist. Which of the following diagnoses are you suspecting?

Correct Answer: D

Rationale: The correct answer is D: Small cell undifferentiated hepatoblastoma. In this case, the key features to consider are the patient's age (9 months old), large liver mass with lung metastases, and elevated alpha-fetoprotein level. Small cell undifferentiated hepatoblastoma is commonly seen in infants, presents as a large liver mass, and frequently metastasizes to the lungs. The alpha-fetoprotein level in this case is also elevated, which is typical for hepatoblastoma. Pure fetal histology hepatoblastoma (A) is less common in older infants, and the presence of lung metastases is not typical. Embryonal sarcoma (B) typically presents as a solitary mass without metastases. Fibrolamellar hepatocellular carcinoma (C) is rare in infants and does not typically present with elevated alpha-fetoprotein levels. Thus, based on the clinical presentation and imaging findings, small cell undifferentiated hepatob

Correct Answer: B

Rationale: The correct answer is B: Administer L-asparaginase immediately after the methotrexate infusion. This sequence is appropriate because methotrexate can interfere with the activity of L-asparaginase if given concurrently, affecting the efficacy of both drugs. Administering L-asparaginase immediately after the methotrexate infusion allows for optimal therapeutic effects of both medications without compromising their individual actions. Choice A (Administer L-asparaginase during the methotrexate infusion) is incorrect because it may lead to drug interactions and reduced effectiveness of both drugs. Choice C (Administer both drugs at the same time) is incorrect for the same reason as choice A. Choice D (Administer methotrexate 24 hours after the asparaginase) is incorrect as it does not follow the optimal timing for these medications during treatment.

Correct Answer: D

Rationale: The correct answer is D: Thrombomodulin. Thrombomodulin binds to thrombin and changes its function from procoagulant to anticoagulant by activating protein C. This leads to the downregulation of fibrinogen formation. Protein C (choice A) and its cofactor Protein S (choice B) are involved in the anticoagulant pathway but do not directly alter thrombin's function. Antithrombin (choice C) inhibits thrombin and other coagulation factors, but it doesn't specifically change thrombin's function from procoagulant to anticoagulant.

Correct Answer: B

Rationale: The correct answer is B. Platelet transfusions are rarely successful in patients with autoimmune thrombocytopenia. Rationale: 1. Patients with autoimmune thrombocytopenia have low platelet levels due to immune destruction. 2. Platelet transfusions may not be effective as the underlying autoimmune process continues to destroy transfused platelets. 3. Reviewing transfusion records of these patients would likely show low success rates of platelet transfusions. Summary of Incorrect Choices: A: Frozen storage of platelets increasing units available is not directly related to the success of platelet transfusions in autoimmune thrombocytopenia. C: Platelet units do carry a risk of transmitting hepatitis C infection, so this conclusion is incorrect. D: Preference for pooled donor platelets over single-donor platelets does not address the success of platelet transfusions in autoimmune thrombocytopenia.

Correct Answer: D

Rationale: The correct answer is D: Transmembrane iron exporter. Ferroportin is a transmembrane protein that functions as an iron exporter, allowing iron to move out of cells. This is crucial in iron metabolism as it facilitates the release of iron from cells into the bloodstream for transport to other tissues. A: A form of storage iron in intestinal mucosal cells - This is incorrect as ferroportin is not involved in storing iron in cells. B: A transport protein in the plasma - This is incorrect as ferroportin is not primarily a plasma protein but rather a transmembrane protein. C: A receptor protein on the surface of erythroid progenitors - This is incorrect as ferroportin is not a receptor protein but an exporter protein.