Page 343 - Concise Pathology for Exam Preparation ( PDFDrive )

328 SECTION II Diseases of Organ Systems

Stab form

Metamyelocyte

Neutrophil
Myelocyte

FIGURE 12.7. PBS showing a markedly raised leukocyte count with granulocyte precursors
ranging from myeloblasts, myelocytes and metamyelocytes to mature neutrophils. Segmented
neutrophils and myelocytes predominate.

Laboratory diagnosis:
• Peripheral smear (Fig. 12.7)
- Normocytic normochromic anaemia
- Total leukocyte count is markedly raised, typically between 100 3 10 and
9
300 3 10 /L.
9
- Granulocyte precursors ranging from myeloblasts, myelocytes and metamyelo-
cytes to mature neutrophils are seen. Segmented neutrophils and myelocytes
predominate.
- Myeloblasts are less than 10%.
- Increase in basophils and eosinophils is observed.
- Platelets are normal or increased.
• Bone marrow
- Hypercellular bone marrow with marked proliferation of all granulocytic elements
- Twenty to thirty percent of patients show mild bone marrow fibrosis in late stages.
• Philadelphia chromosome (Ph) is positive in more than 95% of cases, in all three
phases. This is a reciprocal translocation between the long arms of chromosome 9 and
chromosome 22 (t9; 22).
• Leukocyte alkaline phosphatase (LAP) score is very low, usually less than 5 (normal
20–100).
2. Accelerated phase of CML: CML may transform itself to a blastic phase with or with-
out going through an accelerated phase. Features of accelerated phase are the following:
(a) Progressive anaemia
(b) Increase in splenic size
(c) Increase in total leukocyte count with an increase in circulating immature cells
(blast cells 10–19% in the peripheral blood/or bone marrow)
(d) Peripheral blood basophilia (. 20%)
3
(e) Persistent thrombocytosis (. 1,000,000/mm ) or thrombocytopenia (, 100,000/mm )
3
not responsive to therapy
(f) Cytogenetic evidence of clonal evolution (cytogenetic changes in addition to Ph
chromosome, eg, trisomy 8, etc.)

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