Leukemia

Leukaemia

Dr. Sura obay Aldewachi

At the end of this lecture you will learn the following:

Definition of leukemia. Acute Leukemia: etiology, pathology, pathogenesis, clinical features, hematological features. FAB classification of ALL and AML.

Leukemia: Malignant Disease of WBC Forming tissue or other hemopoietic elements: Lymphoblastic (ALL) Acute Myeloid (AML) Lymphatic (CLL) Chronic Myeloid (CML) ALL is most common in children while AML incidence increase with age (adults).

Aetiology of acute leukemia 

Unknown in individual case, but risk factors are: Viral Radiation: people exposed to high level of radiation (atomic bumb) have an increased risk of developing acute leukemia. Drugs: like chemotherapy for other kinds of cancer. Chemicals: like paints and benzene. Genetics factors: certain genetic disorders like Down syndrome, are associated with increased risk of acute leukemia.

Pathology

Proliferating abnormal and immature cells (blast) accumulating in the marrow suppress the growth of normal hemopoietic cells by physical displacement and by other poorly understood mechanisms. Eventually this suppression manifested as bone marrow failure, Which account for the major clinical presentation. Blast cells spill out in to the blood and infiltrate the spleen , lymph nodes and other tissues.

Pathology:

BLAST CELLS
Tissue invasion (L.N., spleen, liver, skin, C.N.S)
BLOOD Pancytopenia + Blastaemia Normal Haemopoiesis (Depressed)
Bone Marrow

Pathogenesis

The principle pathogenic defect in acute leukemia is a block in differentiation. Both myeloid and lymphocytic acute leukemia arises from genetic defect in hematopoietic proginator cells. This defect result from acquired mutations in specific lineage-transcription factors that regulate the differentiation of immature lymphoid or myeloid progenitors.

Clinical features

Abrupt onset of symptoms Patients presented with: Anemia: (pallor, weakness, tiredness, and SOB) Bleeding tendency: spontaneous bruising, nasal bleeding, bleeding gums. Repeated infections: fever and septicemia. Bone pain and tenderness resulting from marrow expansion and infiltration of subperiosteum. Thymic mass in ALL. CNS manifestation from meningeal spread more common in children than adult and ALL than AML.

Blood Picture: Hb Clinically (Normochronic - - - - Pallor, Tiredness Anaemia - - - - Dyspnea, etc. . . =4-9 g/dl) Platelet Count - - - Bleeding (Thrmbocytopenia Tendency = 10 – 80 x 109/L) Neutrophil - - - Infections count (Fever, septicoemia) ( 0.1 – 1.5 x 109/L)Organ infiltration: Lymphadenopathy (systemic) Hepatosplenomegaly - Gum Hypertrophy in Monocytic leukaemia (rarely, skin, bone, C.N.S) Viral Fungal Bacterial
Total WBC count Normal, low, or increased

Leukaemia: Neoplastic disease of WBC forming tissue.Classification (FAB)I. Acute lymphoblastic leuk. ALL Morphological L1 – Monomorphic type . . . . Good riskL2 – Heterogenous type L 3 – Burkitt’s type Immunological 1) Non T, Non B ALL (common) good risk ALL2) T- ALL3) B- ALL

II. Acute Myeloid Leukaemia (AML) [ FAB]M0 AML . . . Poorly differentiated M1 AML . . . Without Maturation M2 AML . . . With Maturation M3 AproL . . . Promyelocytic M4 AMML . . . MyeloMonocyticM5 AMOL . . . Monocytic M6 A. ErythroLeukaemia M7 A. Megakaryoblastic LAge groups : ALL – mostly in children AML – mostly in Adults