Question
The blood smear shown in the photomicrograph below is from a 67-year-old female with pancytopenia, a markedly enlarged spleen, and extramedullary hematopoiesis. She is found to have a Jak-2 mutation. What is the diagnosis?
A. Chronic myelofibrosis.
B. Chronic myeloid leukemia.
C. Hairy cell leukemia.
D. Metastatic breast carcinoma.
Show Answer
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Correct Answer » A
Explanation
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The diagnosis in this case is chronic myelofibrosis.
The tear drop shaped red cells and normoblast in this blood smear are indicative of a fibrotic marrow. While other tumors can cause a myelophthisic process, JAK-2 mutations are seen most frequently in three chronic myeloproliferative disorders: polycythemia vera, essential thrombocythemia, and chronic myelofibrosis. Jak-2 mutations are particularly characteristic of polycythemia vera – but given the markedly enlarged spleen and extramedullary hematopoiesis in this case, chronic myelofibrosis is a better guess (not to mention that polycythemia vera wasn’t one of the choices.).
