Practice questions answers myeloid neoplasms II

Practice questions answers

Myeloid neoplasms II

© Jun Wang, MD, PhD

1. C. The presence of immature white cells in a background of sudden onset of anemia and bleeding is suspicious for acute leukemia, either myeloid or lymphocytic. Since the diagnosis of acute leukemia is based on the quantity of blast in either peripheral blood or bone marrow, flow cytometry studies would be the most important test to confirm the diagnosis. Biopsy of the gum ulcer would not yield any useful information since the disorder is hematopoietic. Blood culture is for infections. Immunofixation is used to detect monoclonal immunoglobulin, as seen in plasma cell disorders, or tumors with plasma cell differentiation, such as multiple myeloma, plasmacytoma, monoclonal gammopathy of undetermined significance (MGUS), and lymphoplasmacytic lymphoma. Monospot is used to detect heterophile antibodies, as seen in infectious mononucleosis.

2. D. This patient presents with pancytopenia and blasts are seen in peripheral smear as shown. This is most likely acute leukemia, in which the normal hematopoiesis was suppressed by tumor cells in the bone marrow. ADAMTS13 mutation is seen in thrombotic thrombocytopenic purpura. Autoimmune process reduces platelet count in immune thrombocytopenic purpura, both acute or chronic, or heparin induced thrombocytopenia. Endothelial injury associated thrombocytopenia can be seen in hemolytic-uremic syndrome and atypical hemolytic-uremic syndrome, or disseminated intravascular coagulation (DIC). Viral infection associated thrombocytopenia can be seen in HIV induced thrombocytopenia.

3. C. Acute myeloid leukemia is diagnosed when there are more than 20% of myoloblasts or with confirmed genetic abnormalities. For this patient, the blast count is less than 20%. So genetic studies is the test to confirm the diagnosis. Also see discussion of question 1.

4. A. These blasts express myeloblast markers (CD33 and CD34) but not lymphoblast (TdT, CD3, CD20, etc). With the finding of t(8;21)(q22;q22), even the blast count is less than 20%, the diagnosis of acute myeloid leukemia is made. APL with PML-RARA usually has increased promyelocytes and t(15;17)(q22;q12). Acute lymphoblastic leukemia has increased lymphoblasts that are positive for TdT and B cell or T cell markers. Chronic myelogenous leukemia and leukemoid reaction have increased mature white cells but not blasts.

5. E. AML with t(8;21)(q22;q22.1) involves fusion of RUNX1 and RUNX1T1. Fusion of ABL and BCR is seen in chronic myelogenous leukemia. Fusion of CBF-beta and MYH11 is seen in AML with inv(16)(p13.1q22). JAK2 mutation can be seen in essential thrombocythemia, polycythemia vera, and primary myelofibrosis. RAR alpha abnormality is seen in APL with PML-RARA.

6. B. This patient has pancytopenia and numerous atypical cells with Auer rods (faggot cells). Immature myelocytes with coarse granules are present. This is most likely APL with PML-RARA. AML with inv(16)(p13.1q22) usually presents with myeloblasts, monoblasts and promonocytes, but not faggot cells. Acute lymphoblastic leukemia has increased agranular lymphoblasts that are positive for TdT and B cell or T cell markers. Chronic myelogenous leukemia and leukemoid reaction have increased mature neutrophils, basophils and eosinophils, but not blasts, promyelocytes or faggot cells.

7. D. See discussion of question 5.

8. C. t(15;17)(q22;q12) is seen in APL with PML-RARA. t(9;22) (q34;q11) is seen in chronic myelogenous leukemia. 7q- can be seen in various myeloid neoplasms, including myelodysplastic syndrome and associated acute myeloid leukemia. t(8;21)(q22;q22) can be seen in AML with t(8;21)(q22;q22.1), which is more commonly characterized by blasts, scattered Auer rods and chunky cytoplasmic granules. inv(16)(p13.1q22) is seen in AML with inv(16)(p13.1q22), characterized by myeloblasts, monoblasts and promonocytes, but not faggot cells.

9. A. APL with PML-RARA can be treated with all-trans retinoid acid. Folate, iron and vitamin B12 and vitamin K are used to treated associated anemia or coagulopathy, but not leukemia.

10. A. APL with PML-RARA has higher risk to develop disseminated intravascular coagulation before or during induction chemotherapy, as seen in this patient, supported by prolong aPTT, PT, elevated D-dimer and reduced fibrinogen. Heparin induced thrombocytopenia has history of heparin usage, and usually has thrombosis. Immune thrombocytopenia has isolated thrombocytopenia, with normal PT, aPTT and fibrinogen, etc. Sepsis may cause disseminated intravascular coagulation as well, but blood culture should be positive. Vitamin K deficiency, including warfarin associated coagulopathy has prolonged PT and normal aPTT in mild cases, and prolonged PT and aPTT in severe cases. The platelet count, fibrinogen and D-dimers are usually within normal range.

11. A. This case is characterized by leukocytosis with immature white cells. The morphology of large round nuclei, prominent nucleoli and expression of CD33 and CD34 but not TdT and other T or B cell markers are consistent with myeloblast. Since its population is more than 20%, this is most consistent with acute myeloid leukemia. APL has increased number of promyelocytes and frequently pancytopenia and faggot cells. Acute lymphoblastic leukemia has increased lymphoblasts that are positive for TdT and B cell or T cell markers. Chronic myelogenous leukemia and leukemoid reaction have increased mature neutrophils, basophils and eosinophils, but not blasts, promyelocytes or faggot cells.

12. B. This case is characterized by have markedly increased mature neutrophils, basophils, and mildly increased number of myeloblasts. With a low LAP score, this is consistent with chronic myelogenous leukemia. Acute myeloid leukemia is diagnosed when there are more than 20% of myoloblasts or with confirmed genetic abnormalities. Chronic myelomonocytic leukemia has persistent absolute (≥ 1 x 10⁹/L) and relative (> 10%) peripheral blood monocytosis. Essential thrombocythemia has isolated megakaryocyte proliferation and thrombocytosis, but not leukocytosis or erythroid hyperplasia. Leukemoid reaction has high, not low, LAP scores.

13. C. t(9;22) (q34;q11) is seen in almost all case of chronic myelogenous leukemia. inv(16)(p13.1;q22) is seen in AML with inv(16)(p13.1q22). t(8;21)(q22;q22) is seen in AML with t(8;21)(q22;q22.1). t(11;14)(q13;q32) is seen in mantle cell lymphoma. t(15;17)(q22;q12) is seen in APL with PML-RARA.

14. A. t(9;22) (q34;q11) in chronic myelogenous leukemia results a fusion of ABL and BCR. Fusion of CBF-beta and MYH11 is seen in AML with inv(16)(p13.1q22). JAK2 mutation can be seen in essential thrombocythemia, polycythemia vera, and primary myelofibrosis. Fusion of RUNX1 and RUNX1T1 is seen in AML with t(8;21)(q22;q22.1).

15. B. Hepatosplenomegaly seen in myeloproleferative neoplasms is due to extramedullary hematopoiesis.

16. D. The patient has a history of chronic myelogenous leukemia and now has markedly increased number of myeloblasts. This is blast phase of chronic myelogenous leukemia. Acute myeloid leukemia is diagnosed when there are more than 20% of myoloblasts or with confirmed genetic abnormalities, without history of chronic myelogenous leukemia. Acute lymphoblastic leukemia has increased lymphoblasts that are positive for TdT and B cell or T cell markers. Chronic myelogenous leukemia accelerated phase has 10-19% blasts in blood or marrow. Primary myelofibrosis does not have history of chronic myelogenous leukemia nor increased blasts.

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