A 13-year-old Hispanic girl is found to have a WBC count of 6,500/mm3 with 40% Auer rod–containing granular blasts that, by flow cytometry, express very bright CD33 but are negative for human leukocyte antigen–DR isotype (HLA-DR). She is oozing blood around her peripheral IV site. Coagulation studies reveal an international normalized ratio (INR) of 3.4, a fibrinogen of 170, and a markedly elevated D-dimer. Marrow aspirate shows nearly 90% blasts with a similar morphology. You send the marrow to the fluorescence in situ hybridization (FISH) lab and request STAT testing for the most likely recurrent genetic abnormality based on the clinical presentation. How do you plan to initiate therapy?

Correct Answer: B

Rationale: The correct answer is B: Begin therapy with all-trans retinoic acid (ATRA) immediately while aggressively managing coagulopathy with blood product support. The patient's presentation is consistent with acute promyelocytic leukemia (APL), indicated by the presence of Auer rod-containing blasts, very bright CD33 expression, and coagulopathy (elevated INR, low fibrinogen, elevated D-dimer). APL is associated with a specific genetic abnormality involving the PML-RARA fusion gene. ATRA is the mainstay of induction therapy for APL as it induces differentiation of leukemic promyelocytes. Aggressive management of coagulopathy is crucial to prevent life-threatening bleeding complications. Incorrect answers: A: Performing a lumbar puncture is not necessary at this stage as the patient's symptoms and laboratory findings point towards APL, not central nervous system involvement. C: Dexamethasone and hydroxyurea are not

Correct Answer: C

Rationale: The correct answer is C: Reversible inhibition of cyclooxygenase 1. NSAIDs work by reversibly inhibiting cyclooxygenase enzymes, particularly COX-1 and COX-2, which are involved in the synthesis of prostaglandins. In this case, reversible inhibition is crucial because it allows for the temporary suppression of prostaglandin production, leading to pain relief and anti-inflammatory effects. Explanation of other choices: A: Irreversible inhibition of cyclooxygenase 1 - This is incorrect because NSAIDs typically do not irreversibly inhibit COX-1. B: Irreversible inhibition of cyclooxygenase 2 - This is incorrect because NSAIDs do not irreversibly inhibit COX-2. D: Reversible inhibition of cyclooxygenase 2 - This is incorrect because while NSAIDs can inhibit COX-2, the primary target is COX-1 for their therapeutic effects.

Correct Answer: D

Rationale: The correct answer is D. A malignancy of hematopoietic origin does not inherently make general anesthesia unsafe. This is because anesthesia risk is typically influenced by factors such as airway patency, respiratory function, and cardiac status. Choices A, B, and C all indicate potential complications that could make general anesthesia unsafe, such as airway obstruction due to a large mediastinal mass (A), compromised tracheal cross-sectional area (B), and impaired respiratory function (C). These factors would necessitate careful consideration and potential modifications in the anesthesia plan to ensure patient safety.

Correct Answer: C

Rationale: The correct answer is C because obtaining bone marrow under general anesthesia carries inherent risks that make it greater than minimal-risk. Here's a step-by-step rationale: 1. General anesthesia poses risks such as allergic reactions, breathing problems, and potential complications, making the procedure more than minimal-risk. 2. Even though bone marrow assessments are routine for leukemia patients, the use of general anesthesia elevates the risk level. 3. The fact that the results are not shared with the treating oncologist and no therapeutic interventions are based on them indicates that the procedure is solely for research purposes, emphasizing the risk-benefit analysis. 4. Choice A is incorrect because the use of general anesthesia increases the procedure's risk level beyond routine. 5. Choice B is incorrect as the focus should be on the inherent risks of general anesthesia, not just the number of procedures performed. 6. Choice D is irrelevant to the risk assessment of the specific procedure and does not address the immediate safety concerns associated with general anesthesia.

Correct Answer: A

Rationale: The correct answer is A: Burkitt leukemia/lymphoma. This diagnosis is supported by the presence of abnormal cells that are CD10+, CD19+, CD20+, sIg+, which are characteristic of Burkitt lymphoma. The absence of TdT– indicates that it is not T-cell ALL. B-cell ALL would typically show TdT positivity. Hematogones are immature B-cell precursors commonly seen in the bone marrow of healthy children and do not typically present with the described clinical picture. The high percentage of abnormal cells in both blood and bone marrow, along with the specific immunophenotype, point towards Burkitt leukemia/lymphoma.