Chapter 12: Acute leukemias Flashcards
What are leukemias?
Disorders characterized by the accumulation of white cells in the bone marrow and the blood
Why do leukemias causes disease?
(1) they cause bone marrow failure
2) they infiltrate organs (liver, spleen, lymph nodes, meninges, brain, skin, testes.
How are leukemias classified?
Leukemias are classified as acute or chronic, and further classified as lymphoid or myeloid.
What are acute leukemias?
Acute leukemias are aggressive diseases characterized by malignant transformation of hematopoietic stem cells or early progenitors.
What three general cellular abnormalities are often present in acute leukemias?
(1) increased rate of proliferation
(2) reduced apoptosis
(3) A block in cellular differentiation
What is the dominant clinical feature of acute leukemias?
accumualtion of blast cells in the bone marrow and peripheral blood along with bone marrow failure.
How is acute leukemia diagnosed?
Acute leukemia is diagnosed by the presence of over 20% blast cells in the blood or bone marrow.
How is acute leukemia sub-divided?
(1) acute myeloid leukemia (Myeloblasts)
2) acute lymphoid leukemia (Lymphoblasts
How is ALL differentiated from AML?
ALL usually shows no differentiation (except B cell ALL). AML typically shows a greater degree of differentiation.
What is hybrid acute leukemia?
Leukemias that show characteristics of both ALL and AML.
What is the epidemiology of ALL?
ALL is the most common leukemia in children. Peak age is 3-7 years old falling off after 10 years and rising slightly after 40 years old. T-ALL seems to favor males.
What are the three morphological clssifications of ALL?
(1) L1 has small blasts with scanty cytoplasm
(2) L2 has larger blast cells with more prominent nucleoli and cytoplasm
(3) L3 has largest blasts with prominent nucleoli, strongly basophilic cytoplasm and vacuoles.
Immunophenotyping can be used to differentiate ALL cells into what categories?
(1) Early pre-B
(2) Pre-B
(3) B-cell
(4) T-cell
What clinical features are associated with bone marrow failure caused by ALL?
(1) Anemia
(2) Neutropenia
(3) thrombocytopenia
What clinical features are associated with organ infiltration caused by ALL?
(1) Tender bones
(2) Lymphadenopathy
(3) Hepatosplenomegaly
(4) meningeal syndrome
(5) fever
(6) rarely testicular swelling or mediastinal compression.
What blood cell abnormalities are often seen with ALL?
Normochromic, normocytic anemia with thrombocytopenia. Hyper cellular bone marrow with over 20% blasts.
What abnormal biochemical test results may be caused by ALL?
(1) increased serum uric acid
(2) Increased serum lactate dehydrogenase
(3) rarely hypercalcemia
(4) Lytic bone lesions.
(5) enlarged thymus or lymph nodes (T-ALL)
What is the differential diagnosis for ALL?
(1) AML
(2) Aplastic anemia
(3) Marrow infiltration by other malignancies
(4) Infections (mono, pertusis)
(5) juvenile rheumatoid arthritis
(6) Immune thrombocytopenic purpura.
Why is cytogenetic and molecular genetic information concerning ALL significant?
Because the cytogenetic and molecular genetic characteristics of the malignancy profoundly impact prognosis.
What effect does ploidy have on ALL?`
Hyperdiploid (greater than 50 chromosomes) ALL generally has as good prognosis.
Hypodiploid ALL generally is associated with a poor prognosis.
What is the most common specific genetic abnormality in ALL?
t(12; 21) (p13; q22) TEL, AML1 translocation. This creates the TEL-AML1 fusion protein which suppresses normal AML1 which controls hematopoietic transcription.
What is the association between the philadelphia chromosome and ALL?
t(9; 22) philadelphia chromosome increases with age and is associated with a poor prognosis.