1What is hematopoietic neoplasia?
Uncontrolled, clonal proliferation of blood-forming cells.
2What is a lymphoproliferative disorder?
Unregulated, clonal proliferation of lymphocytes.
3What are the two major types of lymphoproliferative neoplasia?
Lymphoma and primary lymphoid leukemia.
4Where does lymphoma originate?
Lymph nodes or extranodal tissues outside the bone marrow.
5Where does primary lymphoid leukemia usually originate?
Bone marrow.
6What is a myeloproliferative disorder?
Unregulated, clonal proliferation of non-lymphoid hematopoietic cells.
7Which cell lineages are affected by myeloproliferative disorders?
Granulocytic, monocytic, erythroid, and megakaryocytic.
8What is myeloid sarcoma?
An extremely rare myeloid neoplasm arising outside bone marrow.
9What is primary leukemia?
Clonal proliferation of neoplastic hematopoietic cells usually originating in bone marrow.
10What defines acute leukemia?
Immature-appearing neoplastic cells with more than 20% blasts in bone marrow.
11What is the typical disease course of acute leukemia?
Aggressive, rapidly progressive, and associated with poor prognosis.
12What does ALL stand for?
Acute lymphoblastic leukemia.
13What does AML stand for?
Acute myeloid leukemia.
14Why can acute leukemia not always be classified by microscopy alone?
Immature lymphoid and myeloid blasts can look similar.
15What does positive CD79a staining indicate in acute leukemia?
B-cell lineage, supporting B-ALL.
16What defines chronic leukemia?
Proliferation of mature-appearing neoplastic cells with slow progression.
17What is the most common chronic leukemia?
Chronic lymphocytic leukemia (CLL).
18What are examples of chronic leukemias?
CLL, chronic granulocytic leukemia, and polycythemia vera.
19What is myelophthisis?
Replacement of normal bone marrow by neoplastic cells, suppressing normal blood cell production.
20Which cytopenias commonly occur with acute leukemia?
Anemia, neutropenia, and thrombocytopenia.
21Why do acute leukemias commonly cause cytopenias?
Neoplastic blasts replace normal bone marrow cells.
22Why might chronic leukemia be discovered incidentally?
Animals may have extremely high leukocyte counts without obvious clinical signs.
23What WBC count is frequently observed in chronic leukemia?
Greater than 100,000 cells/µL.
24Which is more common: lymphoid or myeloid neoplasia?
Lymphoid neoplasia.
25What is the most common hematopoietic neoplasm?
Lymphoma.
26How is lymphoma typically diagnosed?
Cytology or biopsy of lymph nodes or extranodal tissues.
27What are the two causes of a leukemic blood profile with neoplastic lymphocytes?
Primary leukemia or lymphoma with secondary leukemia.
28What are atypical lymphocytes in this lecture?
Large, immature-appearing lymphocytes with prominent nucleoli.

29What are the major differential diagnoses for circulating atypical lymphocytes?
Primary acute leukemia and lymphoma with secondary leukemia.
30What is secondary leukemia?
Circulating neoplastic lymphocytes from lymphoma originating outside bone marrow.
31Approximately what percentage of lymphoma cases develop blood involvement?
10–20%.
32How do circulating neoplastic cell numbers compare between primary and secondary leukemia?
Usually much higher in primary leukemia.
33Why are severe cytopenias less common in lymphoma with secondary leukemia?
Bone marrow involvement is often patchy or focal.
34Why can AML be mistaken for ALL on a blood smear?
Immature myeloid blasts may resemble lymphoid blasts.
35What does positive myeloperoxidase (MPO) staining support?
Acute immature cell myeloid leukemia.

36What characterizes acute myeloid leukemia without maturation?
Very immature cells with minimal expression of lineage-specific markers.
37What is mastocythemia?
Presence of mast cells in peripheral blood, not normal!
38What are the two major causes of mastocythemia?
Mast cell neoplasia and inflammatory or infectious diseases (Gastrointestinal and skin inflammation.)
39In dogs, mastocythemia is more commonly associated with what?
Underlying inflammatory disease.
40In cats, mastocythemia is more commonly associated with what?
Underlying mast cell neoplasia.
41Can circulating mast cell numbers alone distinguish inflammation from neoplasia?
No, especially in dogs.
42What mast cell morphology strongly suggests neoplasia?
Large, immature, poorly granulated mast cells.

43A dog has WBC >500,000/µL, numerous blasts, anemia, neutropenia, and thrombocytopenia. What is most likely?
Primary acute leukemia with myelophthisis.

44A dog has WBC 200,000/µL, mostly small mature lymphocytes, and no major cytopenias. What is most likely?
Chronic lymphocytic leukemia.

45A cat with previous GI lymphoma has circulating atypical lymphocytes but normal RBCs and platelets. What is most likely?
Lymphoma with secondary leukemia.

46A severely anemic cat has numerous erythroid precursors but no reticulocytosis. What should you suspect?
Acute erythroid leukemia.
non regenerative!!

47Which virus is strongly associated with acute erythroid leukemia in cats?
Feline leukemia virus (FeLV).