Acute Lymphoblastic Acute Lymphoblastic leukemias - leukemias - ALLALL

Dr.CSBR.Prasad, M.D.

What is leukemia?

Name the two main types of acute leuemias?

Name the two popular classifications used in acute

leukemias?

What is the required blast percentage for the diagnosis of

acute leukemia?

When do you clinically suspect acute leukemia?

Name the stains used to differentiate AML from ALL?

How WHO classification differs from FAB classification of acute

leukemias?

ALL

The acute lymphoblastic leukemias (ALLs) are systemic neoplastic proliferations of lymphoblasts that have their origin in a bone marrow lymphocyte progenitor cell.

ALL

• Disease of the children and young adults

• With a peak incidence at 4yrs of age• The most common childhood

leukemia (80%)• More common in boys • It can occur in adults (less frequent)

ALLClassification: FAB (Morphological, immunological)

• Divided in to 3 types ALL L1, L2 & L3• L1 is most common in children (85%)• L2 is common in adults• 80% of ALLs are of B-cell origin (CD 19)

FAB classificationFAB classificationo L1: small cells predominate 2x the dia of

small lymphocyte, Nuclei round regular, occasional cleft. Nucleoli not visible. Cytoplasm is scanty. Homogeneous population

o L2: heterogeneous in size, share features of L1 & L3. Nuclei show clefts, Nucleoli+

o L3: homogeneous population of large cells, 3-4x dia of small lymphocytes, nuclei are round, oval with prominent nucleoli. Cytoplasm abundant deeply basophilic, Vacuolated.

ACUTE LYMPHOBLASTICLEUKEMIA, L1 (ALL-L1)

L1: small cells predominate 2x the dia of small lymphocyte, Nuclei round regular, occasional cleft. Nucleoli not visible. Cytoplasm is scanty. Homogeneous population

Name the stains employed to distinguish AML from ALL?

PAS – Block positivity

IMMUNOPEROXIDASE STAIN FOR TdT ON A BONE MARROW SMEAR FROM A PATIENT WITH ACUTE LYMPHOBLASTIC LEUKEMIA

The nuclear distribution of the stain corresponds to the location of TdT in the lymphoblasts.

ALL L1 Bone marrow

ALL L2: Heterogeneous in size, share features of L1 & L3. Nuclei show clefts,

Nucleoli+

ACUTE LYMPHOBLASTIC LEUKEMIA, L2 (ALL-L2)The lymphoblasts vary in size, have reticular chromatin, prominent nucleoli, and lack the nuclear irregularity of the blasts. A minority of the lymphoblasts have the cytologic features of ALL-L1. (Wright-Giemsa stain)

ALL - L3: Homogeneous population of large cells3-4x dia of small lymphocytesNuclei are round, oval with prominent nucleoliCytoplasm abundant deeply basophilic, vacuolated

ALL L3 Burkitt’s leukemia

ALL L3 Burkitt’s leukemia

ALL L3 A methyl green pyronine (MGP) stain on the left shows strong uniform staining of the cytoplasm. On the right the cytoplasmic vacuoles stain with oil red 0.

MGP Oil red O

Chromosomal changes

1. Hyperdiploidy: upto 60 chr. Good prognosis

2. Ph’ L2 Poor prognosis3. t(1,19) pre-B ALL, Poor prognosis4. t(8,14) L3, Poor prognosis

Specific CFThe presenting signs and symptoms are similar to

those of AML and are usually related to blood cytopenias.

Lethargy, malaise, fever, and infection are the most common.

T-cell ALL : Mediastinal mass, Testis is involvedALL 3 (Burkitt’s): Maxilla is involved

Denis Burkitt

Aplastic Presentation of ALL

Rarely, patients with ALL present with pancytopenia and a hypoplastic bone marrow. Leukemic blasts may not be identified initially. This hypocellular phase is typically followed by apparent bone marrow recovery and later by overt leukemia in a matter of weeks or a few months.

Some terms

1- Aleukemic leukemia2- Sub leukemic leukemia3- Leukemoid reaction

CYTOLOGIC FEATURES OF BLASTS IN ACUTE MYELOID & ACUTE LYMPHOBLASTIC LEUKEMIAS

AMLAML ALLALLBlast sizeBlast size Medium to large, uniform Variable Small to

medium

CytoplasmCytoplasm Fine granules may be present

Usually scant, a few coarse granules may be seen

Auer rodsAuer rods Present in 60-70% of cases absent

Nuclear chromatin Nuclear chromatin Finely dispersed Fine to coarse

NucleoliNucleoli 2-4, prominent 1-3, indistinct

Other cell typesOther cell types Often dysplastic changes in maturing myeloid cells

Myeloid cells are not dysplastic

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