Chronic Leukemia Flashcards
1
Q
What is chronic leukemia? How does it differ from acute leukemia?
A
- chronic leukemia is the neoplastic proliferation of mature circulating lymphocytes, resulting in a high WBC count
- it is usually an insidious onset (largely asymptomatic) and seen in older adults
- (vs. acute: proliferation of immature blasts, resulting in sudden onset of symptoms)
- patients present with the insidious development of anemia (fatigue), thrombocytopenia* (bleeding), and neutropenia (fever); AKA pancytopenia
- leukemias in general will present with pancytopenia, hepatosplenomegaly, generalized lymphadenopathy
- *(note that CML can actually result in a thrombocytosis instead of a thrombocytopenia)
2
Q
What is CLL? Which cell markers are used in the diagnosis? What do we see on blood smear?
A
- CLL (chronic lymphocytic leukemia) is the proliferation of NAIVE B-cells (these B-cells fail to become functional plasma cells); it is the MC leukemia in adults (occurs in patients older than 60)
- B-cells in CLL are characterized by CD20 (found on all B-cells) and CD5 (normally only found on T-cells)
- blood smear reveals increased number of lymphocytes and “smudge cells”
3
Q
What can CLL result in?
A
- hypogammaglobulinemia (because the naive B-cells involved don’t mature into plasma cells)
- autoimmune hemolytic anemia (if they do manage to mature, they often target RBCs)
- CLL can also result in generalized lymphadenopathy (if so, it is classified as small lymphocytic lymphoma, SLL); this can further progress into diffuse large B-cell lymphoma
4
Q
What is hairy cell leukemia? What characterizes the cells involved in this leukemia? What can it result in?
A
- hairy cell leukemia is the proliferation of MATURE B-cells (vs. CLL, which involves naive B-cells)
- overexpression of cyclin D1 is usually involved
- these B-cells are characterized by hair cytoplasmic extensions/processes and are also positive on TRAP stain (titrate resistant acid phosphatase)
- commonly results in splenomegaly (curiously, it involves the RED pulp rather than the expected white pulp), but does NOT involve the lymph nodes
- dry tap on bone marrow aspiration (also seen with aplastic anemia, myelofibrosis, and myelodysplastic syndrome)
5
Q
Which two leukemias involve the proliferation of mature CD4+ T-cells? Where does this cell type like to infiltrate? What is each leukemia associated with?
A
- (these are commonly considered types of non-Hodgkin lymphomas)
- both ATLL (adult T-cell leukemia lymphoma) and mycosis fungoides involve the proliferation of mature CD4+ T-cells
- CD4+ T-cells often infiltrate the skin to cause a rash
- ATLL is associated with HTLV-1 (human T-cell leukemia virus 1) found in Japan and the Caribbean
- mycosis fungoides is associated with Sezary syndrome (basically, the leukemic phase of mycosis fungoides; look for the presence of cells with cerebriform nuclei in the blood) and with Pautrier microabscesses on skin biopsy
6
Q
What is CML? Which cytologic abnormality drives this leukemia? Which cell lineages are mainly involved? How do we treat it?
A
- CML (chronic myelogenous leukemia) largely involves the proliferation of granulocytes (basophilia is pretty unique to CML!)and megakaryocytes (this is why CML commonly causes thrombocytosis instead of thrombocytopenia); it involves older adults (45-85)
- involves the Philadelphia chromosome, t(9;22): 9’s ABL gene and 22’s BCR combine to form a constitutively active tyrosine kinase
- classically treated with imatinib (Gleevac), which inhibits the bcr-abl tyrosine kinase
7
Q
What is a major differential diagnosis of CML? How can we tell the two apart?
A
- major DDx of CML is any acute infection/leukemoid reaction (as both will result in the prolfieration of granulocytes)
- in CML, the granulocytes have very low levels of LAP (leukocyte alkaline phosphatase); in others, they have high levels of LAP
- additionally, CML has a characteristic basophilia and the granulocytes will also have the Philadelphia chromosome translocation
