Page 390 - Textbook of Pathology, 6th Edition

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Figure 14.19 PBF findings in acute lymphoblastic leukaemia (ALL). The cells are large, with round to convoluted nuclei having high N/C ratio
and no cytoplasmic granularity.
SECTION II

CHEMOTHERAPY. The most useful drugs in the treatment
2. Bone marrow examination. Marrow examination shows
malignant undifferentiated cells of precursor B or T cell of ALL are combination of vincristine, prednisolone,
origin as demonstrated by immunophenotyping. anthracyclines (daunorubicin, adriamycin) and L-aspara-
Megakaryocytes are usually reduced or absent. ginase. Other agents used are cytosine arabinoside and
methotrexate. Though 90% of children with ALL show
3. Cytochemistry. Cytochemical stains may be employed remission with this therapy, patients with T cell ALL and
as an adjunct to Romanowsky staining for determining those with meningeal involvement carry a less favourable
the type of leukaemia. Some of the commonly employed prognosis. CNS involvement is beyond the reach of most
cytochemical stains in characterisation of leukaemic blasts of the cytotoxic drugs used in the therapy of ALL. CNS
in ALL are as under: prophylaxis in such cases is considered after the initial
i) Periodic acid-Schiff (PAS): Positive in immature lymphoid remission has been obtained and includes cranial irradiation
cells in ALL. and course of intrathecal methotrexate or cytosine
ii) Acid phosphatase: Focal positivity in leukaemic blasts in arabinoside.
ALL. BONE MARROW TRANSPLANTATION. Bone marrow
iii) Myeloperoxidase: Negative in immature cells in ALL. (Stem cell) transplantation from suitable allogenic or
iv) Sudan Black: Negative in immature cells in ALL. autologous donor (HLA and mixed lymphocytes culture-
matched) is used in preB and pre-T cell ALL in adults with
v) Non-specific esterase (NSE): Negative in ALL.
relapses. Bone marrow transplantation has resulted in cure
Immunophenotyping. TdT (terminal deoxynucleotidyl in about half the cases.
transferase) is expressed by the nuclei of both pre-B and Prognosis and disease-free survival of children with both
Haematology and Lymphoreticular Tissues
pre-T stages of differentiation of lymphoid cells. Specific pre-B cell an dpre-T cell ALL is better than in adults. Mean
diagnosis is eastablished by following immunopheno- survival with treatment in children without CNS prophylaxis
typing: is 33 months, while with CNS prophylaxis is 60 months or
Pre-B-cell type: Typically positive for pan-B cell markers more. Adult pre-T cell ALL, however, is as grave as AML
CD19, CD10, CD9a. and median survival is 12-18 months. Patients having limited
disease confined to lymph nodes in both pre-B and pre-T
Pre-T-cell type: Typically positive for CD1, CD2, CD3, CD5, cell type have a higher cure rate and better prognosis.
CD7. The salient differences between the two main forms of
Cytogenetic analysis: Leukaemic blasts in pre-B-cell ALL acute leukaemia (AML and ALL) are summarised in
show characteristic cytogenetic abnormality of t(9;22) i.e. Table 14.12.
Philadelphia positive-ALL.
PERIPHERAL(MATURE) B-CELL MALIGNANCIES
Treatment Peripheral or mature B-cell cancers are the most common
lymphoid malignancies. These arise from the stage of
Treatment plan for children with pre-B or pre-T cell ALL is lymphoid cells at which they become committed to B cell
intensive remission induction with combination therapy. development, acquire surface characteristics and begin to
Patients presenting with pre-B or pre-T cell lymphoma are secrete immunoglobulins. It includes following common
treated as a case of ALL. examples.