Morphologic and Cytochemical Characteristics of Childhood Lymphoblastic Leukemia

Cytochemical Staining

Historically, the diagnosis and classification of acute leukemia involved morphologic review of blasts in the peripheral blood and bone marrow smears and cytochemical staining. Cytochemical stains, which are enzymatic colorimetric reactions that occur in the cells of interest, were necessary to assign and confirm myeloid and lymphoid lineage. In the current WHO 2008 Classification of leukemia, immunophenotyping and cytogenetic analysis have largely replaced cytochemical staining in the characterization of acute leukemias. Nonetheless, cytochemical testing remains a useful adjunct assay for the proper classification of acute leukemia in a number of diagnostic settings. This chapter reviews the principles of the most common cytochemical stains, their procedures and guides to interpretation, and results in acute myeloid leukemia.

Multifaceted Approach to the Diagnosis and Classification of Acute Leukemias

Until recently, the diagnosis and classification of acute myeloid (AML) and acute lymphoblastic (ALL) leukemias was based almost exclusively on well-defined morphologic criteria and cytochemical stains. Although most cases can be diagnosed by these methods, there is only modest correlation between morphologic categories and treatment responsiveness and prognosis. The expansion of therapeutic options and improvement in remission induction and disease-free survival for both AML and ALL have stimulated emphasis on defining good and poor treatment response groups. This is most effectively accomplished by a multifaceted approach to diagnosis and classification using immunophenotyping, cytogenetics, and molecular analysis in addition to the traditional methods. Immunophenotyping is important in characterizing morphologically poorly differentiated acute leukemias and in defining prognostic categories of ALL. Cytogenetic and molecular studies provide important prognostic information and are becoming vitally important in determining the appropriate treatment protocol. With optimal application of these techniques in the diagnosis of acute leukemias, treatment strategies can be more specifically directed and new therapeutic approaches can be evaluated more effectively.

A complex translocation, t(4;11;13)(q21;q23;q12-14), in a case of infantile acute lymphoblastic leukemia

Cytogenetic analysis provides valuable prognostic information in children diagnosed with hematologic malignancies. While the t(4;11)(q21;q23) has frequently been reported in patients with acute lymphoblastic leukemia, the additional involvement of chromosome 13 to form a three-way translocation has not been described previously. We report a case of acute lymphoblastic leukemia in a 5-month old infant with a complex t(4;11;13)(q21;q23;q12-14).

Progress in the treatment of adolescents with acute lymphoblastic leukemia

BACKGROUND AND METHODS. The authors studied the clinical and biologic features and treatment response of 358 children with acute lymphoblastic leukemia (ALL), including 90 adolescents, treated on a single multiagent protocol (St. Jude Total Study XI, 1984-1988). This was done to clarify whether the disease differed in adolescents and to determine the degree of improvement in treatment outcome produced by this modern intense chemotherapy.

RESULTS

Compared with the younger children (1-9 years of age; infants 1 year old or younger excluded; n = 257), adolescents (10-18 years of age; n = 90) were significantly more likely to have adverse prognostic features, including T-cell phenotype, L2 blast cell morphologic characteristics, blasts with negative findings for common ALL antigen, and ploidy other than hyperdiploidy greater than 50. Eighty-six of the 90 (96%) adolescents achieved a complete remission, a rate similar to that of the children (97%). Although the event-free survival (EFS) of adolescents was shorter than that of younger children (5-year EFS of 66 +/- 8% versus 75 +/- 5%, respectively; P = 0.04), in this analysis of consecutively treated patients with ALL it showed a significant statistical and clinical improvement as compared with that in our previous study (St. Jude Total Study X, 1979-1983; 5-year EFS rate of 66 +/- 8% versus 37 +/- 5%, respectively; P < 0.001). Within the adolescent group treated on Total Study XI, the EFS was worse for those older than 15 years of age than for those 10-14 years old (46 +/- 15% versus 75 +/- 8%, respectively; P = 0.007). Toxic effects primarily included myelosuppression without severe sequelae. Approximately 96% of the therapy was administered in the outpatient setting.

CONCLUSIONS

The increased frequency of unfavorable clinical and biologic features undoubtedly accounts for the poorer prognosis of adolescents with ALL, a conclusion supported by the lack of independent prognostic importance of age in this study. The authors conclude that approximately two-thirds of adolescents can be cured when treated with this intensive but tolerable therapy, showing that this form of treatment significantly has changed the prognosis of adolescents with ALL.

Chorea, eosinophilia, and lupus anticoagulant associated with acute lymphoblastic leukemia

A child is reported with chorea as the initial presentation of acute lymphoblastic leukemia. Subsequent laboratory studies revealed marked eosinophilia and a lupus anticoagulant. No peripheral or central nervous system lymphoblasts were observed. The chorea, eosinophilia, and lupus anticoagulant all resolved once remission of the acute lymphoblastic leukemia was induced. It is suggested that acute lymphoblastic leukemia be included in the differential diagnosis of chorea and eosinophilia in childhood.