Today’s question will test your ability to recognize, and diagnose, a commonly tested heme/onc topic.
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A 51-year-old male presents to his primary care physician with a chief complaint of fatigue and night sweats for the past two months. The patient has a history of hypertension and is currently being treated with lisinopril and hydrochlorothiazide. Upon examination, vital signs reveal a blood pressure of 130/80 mmHg, a temperature of 99.9°F, a pulse rate of 90/minute, and a respiratory rate of 14/minute. Physical examination shows pallor of the mucous membranes and dry blood in both nares. Muscle strength is evaluated and graded as 4 in all extremities, while an abdominal examination demonstrates hepatosplenomegaly. Laboratory investigations reveal a hemoglobin concentration of 9.0 g/dL, leukocyte count of 13,000/mm3, and platelet count of 45,000/mm3. Analysis of leukocytes indicates a reciprocal translocation of chromosomes 15 and 17. Given the patient’s findings, what is the most likely diagnosis?
A. Acute myeloblastic leukemia without maturation
B. Acute myeloblastic leukemia with granulocytic maturation
C. Acute promyelocytic leukemia
D. Acute myelomonocytic leukemia
E. Acute monocytic leukemia
F. Acute megakaryoblastic leukemia
Detailed Breakdown of Answers + Correct Answer Below ⏬
ANSWER + QUESTION BREAKDOWN
The MENTAL MODEL used to answer this question comes from our detailed test-taking skills masterclass (check it out if you want to elevate your skills). Here’s how to think through this question:
Step 1. Read the last line to get to the heart of the question: “Given the patient’s findings, what is the most likely diagnosis?”
Step 2: Is this a first-, second-, or third-order question?
Answer: 1st order. 1st: Diagnose the condition based on the given information.
Step 3: Read the vignette carefully and ask yourself: “What’s the most likely cause of these findings?”
Step 4. Look at the answer choices and select the option most closely resembling your final thought from “Step 3” above.
GENERAL ANALYSIS
The clinical presentation of the 51-year-old man with fatigue, night sweats, hepatosplenomegaly, anemia, leukocytosis, thrombocytopenia, and a reciprocal translocation of chromosomes 15 and 17 is consistent with a specific type of leukemia.
ANSWER CHOICES:
CHOICE A: Acute myeloblastic leukemia without maturation
Explanation: This is characterized by myeloblasts without maturation and does not typically involve the t(15;17) translocation.
CHOICE B: Acute myeloblastic leukemia with granulocytic maturation
Explanation: This condition involves myeloid cells with some maturation but is not associated with the t(15;17) translocation.
CHOICE C: Acute promyelocytic leukemia
Explanation: APL is characterized by the t(15;17) translocation involving the PML and RARA genes. Additionally, the patient’s symptoms support this diagnosis.
CHOICE D: Acute myelomonocytic leukemia
Explanation: AML involves both myeloid and monocytic cells and is not associated with the t(15;17) translocation.
CHOICE E: Acute monocytic leukemia
Explanation: This predominantly involves monocytic cells and fails to match this patient’s genetic and clinical profile.
CHOICE F: Acute megakaryoblastic leukemia
Explanation: This involves the proliferation of megakaryoblasts and is not associated with the t(15;17) translocation (or clinical symptoms present).
FINAL VERDICT…
The reciprocal translocation between chromosomes 15 and 17 is a hallmark of acute promyelocytic leukemia (APL). This genetic abnormality leads to the fusion of the PML and RARA genes, causing a block in cell differentiation. Symptoms such as fatigue, night sweats, anemia, thrombocytopenia, and bleeding tendencies are characteristic of APL.
CORRECT ANSWER: C) Acute promyelocytic leukemia
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That’s it for question 80!
See you tomorrow 👋