Blood Cancers and Lymphoma Flashcards
Peripheral blood smear
PelgerHuët cells - dysplastic change which are abnormal appearing neutrophils having only two nuclear lobes
Dysplasia associated with myelodysplastic syndromes
PelgerHuet cells
Hypersegmented PMNs
Hypo/hypergranular cells
RBCs - presence of ringed sideroblasts (seen w/ prussian blue), megaloblastoid erythroid precursors, and mishapen erythroid precursors w/ nuclear budding
Megakarycytes may be abnormal and only have a single nuclear lobe or multiple separate nuclei (prawn ball megakaryocytes)
How are myelodysplastic syndromes classified?
Based on # of blasts present w/i marrow
WHO classification:
<5% blasts - MDS is either refractory anemia (RA) or RA w/ ring sideroblasts (RARS)
5-20% blasts in marrow - RA w/ excess blasts (RAEB)
> 20% blasts in marrow = acute leukemia
5q- syndrome
myelodysplastic syndrome which is characterized by megakaryocytes that are uniformly small and monolobated
Sxs of acute leukemia
Fever (secondary to infection), easy fatigability (due to anemia), and bleeding (due to thrombocytopenia)
Both ALL and AML are characterized by a decrease in mature forms of cells and increase in immature forms (blasts which have immature chromatin with multiple nucleoli)
Acute myelogenous leukemia
Epidemiology
Typically adults between ages of 15-39
Risk Factors:
-Akylating chemo
-Radiation
-Myelodysplastic syndromes
-Myeloproliferative neoplasms
-Down syndrome
CD markers for Pt w/ acute myelogenous leukemia
Myeloid markers:
CD13
CD33
Blast markers:
CD34
CD117
Myeloperoxidase (MPO) = stain to differentiate AML from ALL
Auer rods in AML
Abnormal lysosomal structures (primary granules) considered pathognomonic of myeloblasts
Stain red with MPO
Acute promyelocytic leukemia (APL)
APL is also characterized by the
translocation t(15;17), which results in the fusion of the retinoic acid receptor α (RARA) gene on chromosome 17 to the PML unit on chromosome 15
produces an abnormal retinoic acid receptor such that physiologic levels of retinoic acid no longer activate it.
Treatment for APL is with large doses of vitamin A derivatives, such as all-trans-retinoic acid, which inhibits the proliferation of cells of acute myeloid leukemia.
What subtype of acute myelogenous leukemia is associated with gingival infiltrates?
Acute monocytic leukemia
What subtype of acute myelogenous leukemia is associated with marked fibrosis of the bone marrow
Acute megakaryocytic leukemia is associated with acute myelofiborisis
Acute megakaryocytic leukemia is
associated in children younger than 5 years of age with Down syndrome.
Special stains for megakaryocytes include stains for von Willebrand factor and stains for GpIb/IIIa (on platelets).
Acute lymphoblastic leukemia (ALL)
Primarily disease of children and young adults
Lymphoblasts stain positively for TdT (nuclear enzyme)
ALL is associated with CNS infiltration (distinguishes from AML) where malignant lymphoblasts are protected from chemotherapy by the BBB
Pt’s with ALL may be given prophylactic radiation to head
Also, acute lymphoblastic leukemia is associated with Down syndrome after the age of 5
Immunologic classification of acute lymphocytic leukemia
Most of ALL are B-cell origin:
Lymphoblasts express CD19
Few cases are T-cell origin:
Lymphoblasts lack CD19 but instead express T-cell Ags (CD3 and CD7)
CD markers for T cells are CDs less than 10
Many cases of T-ALL involve a mediastinal mass (which may press on the esophagus causing dysphagia) and are clinically similar to cases of T-cell lymphoblastic lymphoma.
Pro B-cell ALL
+TdT (marker for immature cells)
Lacks CD10/cytoplasmic μ/surface Ig
Common B-ALL
+TdT and +CD10
CD10 is called CALLA - common ALL antigen
Pre-B-ALL
Characteristic translocation t(1;19)
+cytoplasmic μ chains
-TdT and -surface Ig
May be + for CD10
Mature B-ALL
Cells have surface Ig
Lack TdT/CD10/ and cytoplasmic μ
Mature B-ALL is the leukemic form of Burkitt’s lymphoma
-Similarly malignant cells have cytoplasmic vacuoles that stain positively with the oil red O lipid stain
Prognosis with ALL
The presence of CALLA (CD10) is a marker of a favorable prognosis, as is the presence of t(12;21), which is the most common chromosomal rearrangement in childhood B-ALL.
t(9;22) is associated with a poor prognosis. Most children with ALL achieve complete remission with
chemotherapy.
____ is the most common leukemia and is similar in may aspects to small lymphocytic lymphoma (SLL)
Chronic lymphocytic leukemia (CLL)
If Pt presents w/ blood findings first = CLL
If they present w/ lymph node findings first = SLL
What sxs are associated w/ chronic lymphocytic leukemia?
CLL has an indolent course - disease is associated w/ long survivial in many cases
Sxs that may develop are related to anemia or infections - malignant cells are non-functional
Lymphadenopathy or splenomegaly may be noted
Minority of Pt - disease may transform into prolymphocytic leukemia or a large cell immunoblastic lymphome (Richters syndrome)
Richter’s syndrome (transformation)
CLL transformation into immunoblastic lymphoma
Prolymphocytic leukemia
Can be transformation from CLL
Characterized by massive splenomegaly and a markedly increased leukocyte count consisting of enlarged lymphocytes having nuclei with mature chromatin and nucleoli
What leukemia is associated with warm AIHA?
CLL - warm autoimmune hemolytic anemia is characterized by finding spherocytes in the peripheral blood
Tx of B-CLL
Rituximab - mAb against CD20 (B cell marker)
Drug is associated w/ increased risk of progressive multifocal leukoencephalopathy (demyelinating disease of CNS caused destruction of oligodendrocytes secondary to reactivation of JC virus)
Hairy cell leukemia
(HCL) - indolent type of mature B-cell leukemia found most often in older males
Signs:
Pancytopenia (due to leukemic infiltration of marrow)
Splenomegaly (most common sign) - leukemic cells infiltrating red pulp (unusual because leukemias preferentially infiltrate white pulp)
These neoplastic cells proliferate in spleen = splenectomy
Peripheral smear of HCL Pt blood
Numerous lymphocytes w/ cytoplasmic projections
Cells stain for acid phosphatase and rx’n is refractory to Tx w/ tartaric acid (tartrate-resistant acid phosphatase [TRAP])
Hairy cells also express pan-B-cell markers (CD19 and CD20) and monocyte marker CD11c
Hairy cells are negative for CD5 and CD10
What does aspiration of marrow in Pt w/ HCL show?
Dry tap
But biopsy shows proliferation of malignant cells w/ fried-egg appearance
Tx of HCL
Purine analogs like cladribine (2-CDA = first-line Tx)
Also pentostatin (also purine analog)
These drugs are resistant to breakdown by adenosine deaminase (enzyme that is deficient in the AR form of SCIDs) - inhibits nucelotide metabolism and leads to the accumulation of toxic amounts of dexyadenosine
Adenosine deaminase (ADA) is an enzyme that converts adenosine to inosine. ADA inhibition results
in the metabolism of deoxyadenosine through an alternate pathway, which is toxic to lymphocytes.
What stain differentiates AML from ALL?
Myeloperoxidase
Myeloblast stain +
Lymoblasts are -
What translocation is associated with acute promyelocytic leukemia?
t(15;17)
17 - retinoic acid receptor alpha (RARA) gene
15 - promyelocytic leukemia (PML) gene
What increases risk for disseminated intravascular coagulation (DIC) in Pt’s w/ acut promyelocytic leukemia (APL)?
The abnormal promyelocytes seen in APL contain numerous primary granules - increases risk of DIC
Staining of lymphoblasts from Pt w/ acute lymphoblastic leukemia (ALL)
Stain positive for terminal deoxynucleotidyl transferase (TdT)
Negative for myeloperoxidase