Page 340 - Concise Pathology for Exam Preparation ( PDFDrive )

12 Haematology 325

• Periodic acid-Schiff (PAS) shows granular positivity in the erythroblasts of M6 as well
as block positivity in blasts of L1 and L2 subtypes of ALL.
• Acid phosphatase shows a strong focal positivity in T-cell ALL.
• Immunophenotyping in acute leukaemias
Primary panel (to distinguish AML from ALL and classify B-ALL and T-ALL)
• Myeloid: CD13, CD33 and CD117
• B Lymphoid: CD19, CD79a(cyt), CD22(cyt) and CD10
• T Lymphoid: CD3(cyt), CD2 and C7
• Nonlineage restricted (primitive stem cell): HLA-R, TDT and CD34
Secondary panel (to diagnose AML of monocytic, erythroid, megakaryocytic lineage and
further subtyping of B and T-cell ALL)
• Myeloid: CD14, CD64, lysozyme, glycophorin A, CD41 and CD61
• B Lymphoid: cytIgM, surface Ig (k/l)
• T Lymphoid: CD1a, membrane CD3, CD5, CD4 and CD8
• Common cytogenetic abnormalities in acute leukaemias are listed in Table 12.14.

TABLE 12.14. Common cytogenetic abnormalities in acute leukaemias
Chromosomal abnormality Type of leukaemia Prognosis
t(8;21)(q22;q12) AMLM2 Favourable
t(15;17)(q22;q12) AMLM3 Favourable
Inv(16)(p13;q32) AMLM4E0 Favourable
Abnormalities of 11q23 AML monocytic Intermediate
del(7q), del(5q), +8, AML with multilineage dysplasia, Unfavourable
+9, del(11q) therapy-related AML
t(9;22)(q34;q11.2) Precursor B ALL Unfavourable
t(4;11)(q21;q23) Precursor B ALL Unfavourable
t(1;19)(q23;q13.3) Precursor B ALL Unfavourable
t(12;21)(q13;q22) Precursor B ALL Favourable
Hyperdiploidy Precursor B ALL Favourable
Hypodiploidy Precursor B ALL Unfavourable

Q. Differentiate between acute lymphoblastic and acute myelogenous
leukaemia (or differentiate between lymphoblast and myeloblast).
Ans. Differences between acute lymphoblastic and acute myelogenous leukaemia are listed
in Table 12.15.

TABLE 12.15. Differences between acute lymphoblastic and acute myelogenous
leukaemia

Acute lymphoblastic
Features leukaemia (ALL) Acute myelogenous leukaemia (AML)
Clinical features
• Age group Children Adults
• Lymphadenopathy Prominent Less prominent
• Hepatosplenomegaly 50–75% Less common
• CNS involvement More common Less common
• Gum involvement Not seen Gum hypertrophy common in M5 type
• Testicular involvement In 10–20% Not seen
• Eye involvement More common Less common
• Bleeding manifestations Less common More common

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