1. Peripheral Blood, Bone Marrow, and Tissue Morphology: Neoplastic Hematology Charles Timmons, MD, PhD UT Southwestern Medical Center at Dallas Dallas, Texas

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3. Hx: 16 yo boy with pallor and bruising. Blood smear shows anemia, thrombocytopenia, leukocytosis (100,000/mm 3, 90% immature cells). Flow cytometry on blood shows cells are TdT+, CD10+, CD3+, CD7+, CD4+, and CD8+. Interpretation: A.AML B.B-cell ALL C.T-cell ALL D.Hematogone hyperplasia E.Neuroblastoma 1

4. Hx: 16 yo boy with pallor and bruising. Blood smear shows anemia, thrombocytopenia, leukocytosis (100,000/mm3, 90% immature cells). Flow cytometry on blood shows cells are TdT+, CD10+, CD3+, CD7+, CD4+, and CD8+. Interpretation: A.AML B.B-cell ALL C.T-cell ALL D.Hematogone hyperplasia E.Neuroblastoma 1 Comment: The cells are T lymphoblasts by morphology and flow cytometry. Hematogones are rarely seen in peripheral blood. High white count and large and small blasts favor T-cell ALL.

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6. Hx: 5 yo boy with bruising and cervical lymph- adenopathy. Blood smear shows pancytopenia and 20% abnormal cells (pictured). Flow cytometry on marrow shows 90% of cells are TdT+, CD10+, CD3+ and CD7+. Interpretation: A.AML B.B-cell ALL C.T-cell ALL D.Hematogone hyperplasia E.Neuroblastoma 2

7. Hx: 5 yo boy with bruising and cervical lymph- adenopathy. Blood smear shows pancytopenia and 20% abnormal cells (pictured). Flow cytometry on marrow shows 90% of cells are TdT+, CD10+, CD3+ and CD7+. Interpretation: A.AML B.B-cell ALL C.T-cell ALL D.Hematogone hyperplasia E.Neuroblastoma 2 Comment: The cells are immunophenotypically precursor T lymphoblasts. Morphologically they correspond to the old L2 designation from the FAB classification system.

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9. Hx: 6 yo boy with bone pain. Blood smear shows pancytopenia, and 5% circulating immature cells (pictured). Flow cytometry on marrow shows 80% cells are TdT+, CD10+ and CD19+. Interpretation: A.AML B.B-cell ALL C.T-cell ALL D.Hematogone hyperplasia E.Neuroblastoma 3

10. Hx: 6 yo boy with bone pain. Blood smear shows pancytopenia but no blasts. Flow cytometry on marrow shows 95% cells are TdT+, CD10+ and CD19+. Interpretation: A.AML B.B-cell ALL C.T-cell ALL D.Hematogone hyperplasia E.Neuroblastoma 3 Comment: This is a blast by morphology and is B phenotype by flow cytometry. Hematogones should show more of a spectrum of maturation and are unlikely to completely replace the normal marrow elements. Solid tumor cells tend to clump rather than cluster.

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12. Hx: 15 yo boy with respiratory distress. Radiology shows cervical and mediastinal lymphadenopathy, which is biopsied. Flow cytometry shows a proliferation of cells that are TdT+, CD10+, CD3+, CD7+, CD4+ and CD8+. Interpretation: A.Myeloid sarcoma B.B lymphoblastic lymphoma C.T lymphoblastic lymphoma D.Hodgkin lymphoma E.Reactive process 4

13. Hx: 15 yo boy with respiratory distress. Radiology shows cervical and mediastinal lymphadenopathy, which is biopsied. Flow cytometry shows a proliferation of cells that are TdT+, CD10+, CD3+, CD7+, CD4+ and CD8+. Interpretation: A.Myeloid sarcoma B.B lymphoblastic lymphoma C.T lymphoblastic lymphoma D.Hodgkin lymphoma E.Reactive process 4 Comment: By morphology and flow cytometry, the immature cells are precursor T lymphoblasts. An extramedullary mass of lymphoblasts is called lymphoblastic lymphoma, although it is part of a biologic continuum referred to as leukemia/lymphoma.

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15. Hx: 16 yo boy with respiratory distress. Radiology shows a mediastinal mass and a pleural effusion, which is tapped. Flow cytometry shows 90% of effusion cells are TdT+, CD10+, CD3+, CD7+, CD4+ and CD8+. Interpretation: A.Myeloid sarcoma B.B lymphoblastic lymphoma C.T lymphoblastic lymphoma D.Hodgkin lymphoma E.Reactive process 5

16. Hx: 16 yo boy with respiratory distress. Radiology shows a mediastinal mass and a pleural effusion, which is tapped. Flow cytometry shows 90% of effusion cells are TdT+, CD10+, CD3+, CD7+, CD4+ and CD8+. Interpretation: A.Myeloid sarcoma B.B lymphoblastic lymphoma C.T lymphoblastic lymphoma D.Hodgkin lymphoma E.Reactive process 5 Comment: By morphology and flow cytometry, the immature cells are T lymphoblasts. An extramedullary mass of lymphoblasts is called lymphoblastic lymphoma, although it is part of a biologic continuum referred to as leukemia/lymphoma.

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18. Hx: 7 yo boy with an recent onset of vomiting and lethargy. Blood smear shows increased neutrophils with a left shift and 8% abnormal cells. Bone marrow contains 60% of the same cells. Flow cytometry shows cells are TdT-, CD10+, CD19+. Interpretation: A.AML B.B-cell ALL C.T-cell ALL D.Burkitt leukemia/lymphoma E.Reactive process 6

19. Hx: 7 yo boy with recent onset of vomiting and lethargy. Blood has increased neutrophils with left shift and 8% abnormal cells. Bone marrow contains 60% of the same cells. Flow cytometry shows cells are TdT-, CD10+, CD19+. Interpretation: A.AML B.B-cell ALL C.T-cell ALL D.Burkitt leukemia/lymphoma E.Reactive process 6 Comment: Flow cytometry shows mature B-cells, and the morphology is that of Burkitt lymphoma, which occasionally can have a leukemic phase.

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21. Hx: 12 yo boy with vomiting, abdominal pain and weight loss. Radiology shows an ileo-cecal mass. Histology of the resection specimen is shown. Flow cytometry on the mass shows cells are TdT-, CD10+ and CD19+. Interpretation: A.Myeloid sarcoma B.B lymphoblastic lymphoma C.T lymphoblastic lymphoma D.Burkitt lymphoma E.Reactive process 7

22. Hx: 12 yo boy with vomiting, abdominal pain and weight loss. Radiology shows an ileo-cecal mass. Histology of the resection specimen is shown. Flow cytometry on the mass shows cells are TdT-, CD10+ and CD19+. Interpretation: A.Myeloid sarcoma B.B lymphoblastic lymphoma C.T lymphoblastic lymphoma D.Burkitt lymphoma E.Reactive process 7 Comment: The “starry-sky” histology can be seen in either lymphoblastic lymphoma or Burkitt lymphoma, but the immunophenotype is of a mature B-cell, consistent with Burkitt lymphoma, and the appearance of the cells also favors Burkitt lymphoma.

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24. Hx: 14 yo boy with a single large cervical lymph node. Lymph node biopsy is shown. Flow cytometry and immunohistochemistry show cells are TdT-, CD19+, CD20+, CD3-. Interpretation: A.Large B-cell lymphoma B.T lymphoblastic lymphoma C.Mature (Peripheral) T-cell lymphoma D.Hodgkin lymphoma E.Reactive process 8

25. Hx: 14 yo boy with a single large cervical lymph node. Lymph node biopsy is shown. Flow cytometry and immunohistochemistry show cells are TdT-, CD19+, CD20+, CD3-. Interpretation: A.Large B-cell lymphoma B.T lymphoblastic lymphoma C.Mature (Peripheral) T-cell lymphoma D.Hodgkin lymphoma E.Reactive process 8 Comment: The neoplastic cells are large and monomorphous, with the immunophenotype of mature B-cells.

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27. Hx: 18 yo boy with abdominal pain, has hepatosplenomegaly, thrombocytopenia and anemia, without adenopathy. Flow cytometry on infiltrate shows cells are TdT-, CD3+, CD4-, CD8-. Interpretation: A.B lymphoblastic lymphoma B.Burkitt lymphoma C.T lymphoblastic lymphoma D.Mature (Peripheral) T-cell lymphoma E.Reactive process 9

28. Hx: 18 yo boy with abdominal pain, has hepatosplenomegaly, thrombocytopenia and anemia, without adenopathy. Flow cytometry on infiltrate shows cells are TdT-, CD3+, CD4-, CD8-. Interpretation: A.B lymphoblastic lymphoma B.Burkitt lymphoma C.T lymphoblastic lymphoma D.Mature (Peripheral) T-cell lymphoma E.Reactive process 9 Comment: The infiltrate is monomorphous, with the immunophenotype of a mature T-cell process, specifically hepatosplenic T-cell lymphoma, which typically infiltrates parenchyma rather than forming a discrete mass.

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30. Hx: 17 yo boy with fever and cervical lymphadenopathy. Lymph node biopsy shown. Immunohistochemistry shows cells are CD3-, CD 4+, CD8-, CD30+, EMA+, ALK+. Interpretation: A.Burkitt lymphoma B.T lymphoblastic lymphoma C.Mature (Peripheral) T-cell lymphoma D.Hodgkin lymphoma E.Reactive process 10

31. Hx: 17 yo boy with fever and cervical lymphadenopathy. Lymph node biopsy shown. Immunohistochemistry shows cells are CD3-, CD4+, CD8-, CD30+, EMA+, ALK+. Interpretation: A.Burkitt lymphoma B.T lymphoblastic lymphoma C.Mature (Peripheral) T-cell lymphoma D.Hodgkin lymphoma E.Reactive process 10 Comment: The infiltrate is composed of large, anaplastic cells with a mature T-cell immunophenotype. In this setting, ALK-positivity is helpful in calling this anaplastic large cell lymphoma.

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33. Hx: 13 yo boy with fatigue, weight loss, night sweats and splenomegaly. Peripheral blood shows anemia and leukocytosis (300,000/mm 3 ). Ancillary test results include normal fetal hemoglobin and karyotype showing t(9;22). Interpretation: A.Acute myeloid leukemia B.Acute lymphoblastic leukemia C.Chronic myelogenous leukemia D.Juvenile myelomonocytic leukemia E.Reactive process 11

34. Hx: 13 yo boy with fatigue, weight loss, night sweats and splenomegaly. Peripheral blood shows anemia and leukocytosis (300,000/mm 3 ). Ancillary test results include normal fetal hemoglobin and karyotype showing t(9;22). Interpretation: A.Acute myeloid leukemia B.Acute lymphoblastic leukemia C.Chronic myeloid leukemia D.Juvenile myelomonocytic leukemia E.Reactive process 11 Comment: Marked leukocytosis with prominent basophils without increased blasts (<10%) indicate chronic phase of CML. t(9;22)(q34;q11.2) indicates a BCR/ABL1 rearrangement.

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36. Hx: 2 yo girl with new onset of fever and bronchitis. Has maculo-papular rash and hepatosplenomegaly. Blood smear has leukocytosis (100,000/mm 3 ), anemia and thrombocytopenia. Ancillary tests include fetal hemoglobin of 80% and normal blood karyotype. Interpretation: A.Acute myeloid leukemia B.Acute lymphoblastic leukemia C.Chronic myeloid leukemia D.Juvenile myelomonocytic leukemia E.Reactive process 12

37. Hx: 2 yo girl with new onset of fever and bronchitis. Has maculopapular rash and hepatosplenomegaly. Blood smear has leukocytosis (100,000/mm 3 ), anemia and thrombocytopenia. Ancillary tests include fetal hemoglobin of 80% and normal blood karyotype. Interpretation: A.Acute myeloid leukemia B.Acute lymphoblastic leukemia C.Chronic myeloid leukemia D.Juvenile myelomonocytic leukemia E.Reactive process 12 Comment: Marked leukocytosis including monocytosis without increased blasts, accompanied by erythroid proliferation and elevation of fetal hemoglobin is characteristic of JMML. BCR/ABL1 fusion is not present.

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39. Hx: 1 yo boy with pallor and a rash. Blood smear shows pan cytopenia and circulating abnormal cells. Interpretation: A.Acute myeloid leukemia B.Chronic myelogenous leukemia C.Acute lymphoblastic leukemia D.Leukoerythroblastic reaction E.Infectious mononucleosis 13

40. Hx: 1 yo boy with pallor and a rash. Blood smear shows pan cytopenia and circulating abnormal cells. Interpretation: A.Acute myeloid leukemia B.Chronic myelogenous leukemia C.Acute lymphoblastic leukemia D.Leukoerythroblastic reaction E.Infectious mononucleosis 13 Comment: The large blasts with ample cytoplasm and prominent nucleoli are suggestive of AML, but the Auer rod is diagnostic.

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42. Hx: 8 yo boy with bruising. Blood smear shows anemia, thrombocytopenia, and leukocytosis (30,000/mm3, 50% blasts). Flow cytometry on marrow shows 50% blasts with TdT+, MPO+, CD13+, CD33+, partial CD19+. Interpretation: A.Acute myeloid leukemia B.Chronic myelogenous leukemia C.Acute lymphoblastic leukemia D.Myelodysplastic syndrome E.Reactive process 14

43. Hx: 8 yo boy with bruising. Blood smear shows anemia, thrombocytopenia, and leukocytosis (30,000/mm3, 50% blasts). Flow cytometry on marrow shows 50% blasts with TdT+, MPO+, CD13+, CD33+. Interpretation: A.Acute myeloid leukemia B.Chronic myelogenous leukemia C.Acute lymphoblastic leukemia D.Myelodysplastic syndrome E.Reactive process 14 Comment: The elevated blast count indicates acute leukemia. Auer rod is diagnostic of a myeloid neoplasm, and flow cytometry agrees. Morphology shows myeloid maturation and a large blunt Auer rod, which often correlates with t(8;21)(q22;q22) and RUNX1/RUNX1T1 fusion.

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45. Hx: 8 yo girl with fever, tonsillitis and lymph- adenopathy. Blood smear shows anemia, thrombocytopenia, and leukocytosis (140,000/mm 3, 60% blasts). Flow cytometry on marrow shows 60% blasts with TdT+, MPO+, CD13+, CD33+, CD11b partial+. Interpretation: A.Acute myeloid leukemia B.Chronic myelogenous leukemia C.Acute lymphoblastic leukemia D.Chediak-Higashi syndrome E.Reactive process 15

46. Hx: 8 yo girl with fever, tonsillitis and lympha- denopathy. Blood smear shows anemia, thrombocytopenia, and leukocytosis (140,000/mm 3, 60% blasts). Flow cytometry on marrow shows 60% blasts with tdT+, MPO+, CD13+, CD33+, CD11b partial+. Interpretation: A.Acute myeloid leukemia B.Chronic myeloid leukemia C.Acute lymphoblastic leukemia D.Chediak-Higashi syndrome E.Reactive process 15 Comment: Increased blasts mark as myelomonocytic lineage, so this is AML. The strange, darkly granulated cells are abnormal eosinophils, morphology that correlates with a karyotype of inv(16) or t(16;16).

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48. Hx: 13 yo girl with fever and swelling of one leg. Blood smear shows anemia and thrombo- cytopenia. WBC 3400/mm 3 with marked left shift. Marrow has 2% blasts but 82% immature myeloid cells as shown. Flow cytometry on marrow shows MPO+, CD33+, CD13 partial+, HLA-DR-, CD34-. Interpretation: A.Acute myeloid leukemia B.Chronic myelogenous leukemia C.Acute lymphoblastic leukemia D.Mast cell leukemia E.Left shift with toxic granulation 16

49. Hx: 13 yo girl with fever and swelling of one leg. Blood smear shows anemia and thrombocytopenia. WBC 3400/mm 3 with marked left shift. Marrow has 2% blasts but 82% immature myeloid cells as shown. Flow cytometry on marrow shows MPO+, CD33+, HLA-DR-, CD34-. Interpretation: A.Acute myeloid leukemia B.Chronic myelogenous leukemia C.Acute lymphoblastic leukemia D.Mast cell leukemia E.Left shift with toxic granulation 16 Comment: Proliferating promyelocytes, which sometimes have multiple Auer rods, rather than myeloblasts characterize the acute promyelocytic form of AML, which is associated with t(15;17) and a PML/RARA fusion.

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51. Hx: 19 yo girl with history of treatment for ALCL 3 years prior. Now with persistent pancytopenia (WBC 800/mm 3, no circulating blasts). Marrow has 80% abnormal cells that by flow cytometry are MPO-, CD33+, CD34-, CD13+, CD11b+, CD14+. Interpretation: A.Acute myeloid leukemia B.Juvenile myelomonocytic leukemia C.Acute lymphoblastic leukemia D.Langerhans cell histiocytosis E.Hemophagocytic lymphohistiocytosis 17

52. Hx: 19 yo girl with history of treatment for ALCL 3 years prior. Now with persistent pancytopenia (WBC 800/mm 3, no circulating blasts). Marrow has 80% abnormal cells that by flow cytometry are MPO-, CD33+, CD34-, CD13+, CD11b+, CD14+. Interpretation: A.Acute myeloid leukemia B.Juvenile myelomonocytic leukemia C.Acute lymphoblastic leukemia D.Langerhans cell histiocytosis E.Hemophagocytic lymphohistiocytosis 17 Comment: The morphology and flow cytometry are those of monoblasts, which is characteristic of therapy-related AML, especially with rearrangements of the MLL gene at chromosome 11q23.

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54. Hx: 1yo boy with pallor and bruising. Blood shows anemia and thrombocytopenia, with mild leukocytosis (10,000/mm 3, 5% circulating blasts). Marrow has 60% abnormal cells that by flow cytometry are MPO-, CD33+, HLA-DR-, CD34-, glycophorin A(CD235a)+. Interpretation: A.Acute myeloid leukemia B.Juvenile myelomonocytic leukemia C.Acute lymphoblastic leukemia D.Burkitt lymphoma/leukemia E.Chronic parvovirus infection 18

55. Hx: 1yo boy with pallor and bruising. Blood shows anemia and thrombocytopenia, with mild leukocytosis (10,000/mm 3, 5% circulating blasts). Marrow has 60% abnormal cells that by flow cytometry are MPO-, CD33+, HLA-DR-, CD34-, glycophorin A(CD235a)+. Interpretation: A.Acute myeloid leukemia B.Juvenile myelomonocytic leukemia C.Acute lymphoblastic leukemia D.Burkitt lymphoma/leukemia E.Chronic parvovirus infection 18 Comment: The morphology and immunophenotype indicate a pure erythroid proliferation of blasts, without a significant myeloid component, making this the pure erythroid variant of AML.

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57. Hx: 1 yo boy with fever and weight loss. Blood shows anemia and neutropenia with 5% circulating blasts. Marrow has 95% abnormal cells that by flow cytometry are MPO-, CD33+, CD34-, HLA-DR-, CD41+, CD61+. Interpretation: A.Acute myeloid leukemia B.Acute lymphoblastic leukemia C.Transient myeloproliferative disorder D.Neuroblastoma E.Langerhans cell histiocytosis 19

58. Hx: 1 yo boy with fever and weight loss. Blood shows anemia and neutropenia with 5% circulating blasts. Marrow has 95% abnormal cells that by flow cytometry are MPO-, CD33+, CD34-, HLA-DR-, CD41+, CD61+. Interpretation: A.Acute myeloid leukemia B.Acute lymphoblastic leukemia C.Transient myeloproliferative disorder D.Neuroblastoma E.Langerhans cell histiocytosis 19 Comment: The immunophenotype and marrow replacement indicate the megakaryoblastic variant of AML. Megakaryoblasts may be small, resembling lymphoblasts. Platelet-like cytoplasmic buds are common but not specific.

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60. Hx: 17 yo boy with inguinal lymphadenopathy. On biopsy, nodal architecture is effaced by a vaguely nodular proliferation of large atypical cells and small lymphocytes. By immuno- histochemistry, the large cells are CD20+, CD45+, BCL6+, EMA+, Oct 2+, BOB1+, but CD15- and CD30-. Interpretation: A.Chronic lymphocytic lymphoma B.Burkitt lymphoma C.Classic Hodgkin lymphoma D.Nodular lymphocyte-predominant Hodgkin lymphoma E.Reactive process 20

61. Hx: 17 yo boy with inguinal lymphadenopathy. On biopsy, nodal architecture is effaced by a vaguely nodular proliferation of large atypical cells and small lymphocytes. By immuno-histochemistry, the large cells are CD20+, CD45+, BCL6+, EMA+, Oct 2+, BOB1+, but CD15- and CD30-. Interpretation: A.Chronic lymphocytic lymphoma B.Burkitt lymphoma C.Classic Hodgkin lymphoma D.Nodular lymphocyte-predominant Hodgkin lymphoma E.Reactive process 20 Comment: The morphology and B-cell immunophenotype are characteristic of the L&H cells (“popcorn cells”) of nodular lymphocyte- predominant Hodgkin lymphoma.

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63. Hx: 17 yo boy with fever, night sweats, weight loss andcervical lymphadenopathy. On biopsy, nodal architecture is effaced by mixed inflammatory cells and large atypical cells. The large cells are CD30+, CD15+, PAX5 weak+, but CD20-, CD45-, EMA-, Oct 2-, BOB1-. Interpretation: A.Chronic lymphocytic lymphoma B.Burkitt lymphoma C.Classical Hodgkin lymphoma D.Nodular lymphocyte-predominant Hodgkin lymphoma E.Reactive process 21

64. Hx: 17 yo boy with fever, night sweats, weight loss andcervical lymphadenopathy. On biopsy, nodal architecture is effaced by mixed inflammatory cells and large atypical cells. The large cells are CD30+, CD15+, PAX5 weak+, but CD20-, CD45-, EMA-, Oct 2-, BOB1-. Interpretation: A.Chronic lymphocytic lymphoma B.Burkitt lymphoma C.Classical Hodgkin lymphoma D.Nodular lymphocyte-predominant Hodgkin lymphoma E.Reactive process 21 Comment: The morphology and immunophenotype are characteristic of the Hodgkin cells and Reed-Sternberg cells of the classical form of Hodgkin lymphoma.

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66. Hx: 5 yo boy, 2yrs post liver transplant, with new onset of lymphadenopathy and ascites. Radiology shows a right lower quadrant mass. A bone marrow aspirate contained the cells shown, which are CD20+ and show in situ hybridization for EBV. Interpretation: A.Acute myeloid leukemia B.Acute lymphoblastic leukemia C.Post-transplant lymphoproliferative disorder D.Infectious mononucleosis E.Hemophagocytic lymphohistiocytosis 22

67. Hx: 5 yo boy, 2yrs post liver transplant, with new onset of lymphadenopathy and ascites. A bone marrow aspirate contains the cells shown, which are CD20+ and show in situ hybridization for EBV. Interpretation: A.Acute myeloid leukemia B.Acute lymphoblastic leukemia C.Post-transplant lymphoproliferative disorder D.Infectious mononucleosis E.Hemophagocytic lymphohistiocytosis 22 Comment: The morphology and immunophenotype fit a large B-cell lymphoma, which here represents a mono- morphous post-transplant lymphoproliferative disorder.

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69. Hx: 4 yo boy with a small painless frontal bone mass, which was resected. Radiology shows multiple lytic bony defects. The cells in the mass are CD1a+, S100+, but are CD68-. Interpretation: A.Myeloid sarcoma B.Peripheral T-cell lymphoma C.Metastatic solid tumor D.Langerhans cell histiocytosis E.Infectious granulomatous process 23

70. Hx: 4 yo boy with a small painless frontal bone mass, which was resected. Radiology shows multiple lytic bony defects. The cells in the mass are CD1a+, S100+, but are CD68-. Interpretation: A.Myeloid sarcoma B.Peripheral T-cell lymphoma C.Metastatic solid tumor D.Langerhans cell histiocytosis E.Infectious granulomatous process 23 Comment: The morphology of twisted and reniform histiocytes with nuclear grooves, and the distinctive immunophenotype are those of Langerhans cells. The eosinophils are helpful but not essential.

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72. Hx: 6 mo girl with a large abdominal mass and elevated serum catecholamines. Bone marrow aspirations contains the cells pictured. Flow cytometry shows the cells to be CD56+. Interpretation: A.Myeloid leukemia/sarcoma B.Lymphoblastic leukemia/lymphoma C.Natural killer cell lymphoma D.Metastatic Wilms tumor E.Metastatic neuroblastoma 24

73. Hx: 6 mo girl with a large abdominal mass and elevated serum catecholamines. Bone marrow aspirations contains the cells pictured. Flow cytometry shows the cells to be CD56+. Interpretation: A.Myeloid leukemia/sarcoma B.Lymphoblastic leukemia/lymphoma C.Natural killer cell lymphoma D.Metastatic Wilms tumor E.Metastatic neuroblastoma 24 Comment: Clumps of small cells are most likely solid tumor. CD56 not only marks natural killer cells but is also a neural cell adhesion molecule. Small cell tumor with elevated catecholamines is diagnostic of neuroblastoma.