Diagnosis of Childhood Acute Myeloid Leukemia

Phenotypic clues that predict underlying cytogenetic/genetic abnormalities in myeloid malignancies: A contemporary review

Precise subclassification of myeloid malignancies per the World Health Organization (WHO) classification system and the International Consensus Classification of Myeloid Neoplasms and Acute Leukaemias (ICC) requires investigation and documentation of the presence of cytogenetic and/or molecular genetic changes. These ancillary studies not only help in diagnosis, but also the prognosis of disease; however, they take time to be completed. In contrast, morphological evaluation of material from the blood and bone marrow specimens of cases where myeloid malignancies are suspected is usually completed quickly. Cytomorphological assessment may predict genetic changes and can be helpful in triaging acuity. This is especially true in haematological emergencies such as acute promyelocytic leukaemia (APL), where prompt APL-specific therapy can be life changing. Similarly, some morphological clues may help identify core binding factor leukaemias where a diagnosis of acute myeloid leukaemia (AML) could be rendered without reaching the 20% blast cutoff with immediate treatment-decision implications, or even a subset of cases of AML with FLT3 ITD/NPM1 mutation(s) which show characteristic features. Even though FISH/cytogenetics and/or PCR are still required for establishing the final diagnosis, evaluation for the presence of specific cytomorphological features that help predict genetic changes can be a useful tool to help guide early therapy.

Comparative study of the efficacy of Wright-Giemsa stain and Liu's stain in the detection of Auer rods in acute promyelocytic leukemia

In view of the importance of Auer rods in the rapid diagnosis of acute promyelocytic leukemia, we compared the results of Wright-Giemsa stain and Liu's stain (a rapid and simple stain, which is also a kind of modified Romanowsky stain) in the detection of Auer rods. This study was based on 53 cases of acute promyelocytic leukemia. Two staining methods were respectively performed on the bone marrow smears of these cases, and presence of Auer rods as well as nuclear features, cytoplasmic features and the degree of granularity of the cytoplasm were compared in each case. Our results showed that the occurrence of Auer rods as well as faggots in leukemic promyelocytes were significantly higher under Liu's stain than under Wright-Giemsa stain. Significant differences also existed in the occurrence of hypergranular cells and cytoplasmic protrusions between smears stained with Liu's stain and Wright-Giemsa stain. Liu's stain is important for the rapid diagnosis of suspicious APL, especially in recognizing Auer rods.

Osteoarticular manifestations as initial presentation of acute leukemias in children and adolescents in Bahia, Brazil

OBJECTIVE

This study was to determine the prevalence and characteristics of the osteoarticular manifestations on initial clinical presentation of acute leukemias (ALs) on childhood in the state of Bahia, Brazil.

MATERIALS AND METHODS

This retrospective study assessed the medical records of 406 patients with AL from January 1995 to December 2004.

RESULTS

Acute lymphocytic leukemia (ALL) was diagnosed in 313 (77.1%) patients and acute myeloid leukemia (AML), in 93 (22.9%) patients, including 241 males (59.4%) and 165 females (40.6%). Age ranged from 9 months to 15 years (average: 6.18 y). The most common presenting features were fever (18.5%), musculoskeletal diffuse tenderness (15.0%), pallor (11.4%), and leg tenderness (5.7%). Prior referral to our center, the most frequent initial diagnosis was anemia (15.8%), leukemia (15.0%), amygdalitis (3.7%), and rheumatic fever (2.7%). Osteoarticular manifestations were found on 54.7% of the patients with AL, with a higher frequency among patients between 1 and 9 years of age (58.7%, P=0.0007). The presence of joint tenderness (16.2% in ALLx5.4% in AML), arthritis (26.6% in ALLx9.7 in AML), bone tenderness (26.1% in ALLx16.1% in AML), limb tenderness (49.5% in ALLx25.8% in AML), and antalgic gait (32.8% in ALLx9.7% in AML) had higher prevalence on ALL. The large joints, chiefly the knees (10.6%), ankles (9.4%), elbows (4.4%), and shoulders (3.6%) were more often affected.

CONCLUSIONS

AL should be considered on the differential diagnosis of osteoarticular symptoms of unknown etiology in children.

Acute promyelocytic leukemia M3: cytomorphologic, immunophenotypic, cytogenetic, and molecular variants

Acute promyelocytic leukemia (APL) M3 is an acute myeloid leukemia (AML) subtype characterized by proliferation of malignant promyelocytes with mature myeloid immunophenotype and the translocation t(15;17)(q22;q11), which results in the fusion of retinoic acid receptor-alpha (RARalpha) gene on chromosome 17 and the gene PML on chromosome 15. There are three M3 morphologic variants: the typical hypergranular form and the microgranular and basophilic variants. Although most leukemic cells in M3 patients express t(15;17), other cytogenetic abnormalities have also been reported. Also, there are three molecular variants of the PML/RARalpha transcript (bcr1, bcr2, bcr3). Blasts had typical hypergranular appearance (13 patients) with a mature myeloid immunophenotype (HLA-DR(-),CD13(+), and/or CD33(+)) (10 patients) in the majority of patients with M3 followed in this study. The typical translocation [t(15;17)(q22;q11)] was detected by cytogenetic analysis in 5 M3 patients, but PML/RARalpha was positive in 13 out of 15 patients, as assessed by RT-PCR (8 patients with bcr1 and 5 with bcr3 subtype). Cytogenetic diversity was found in three patients (1 with t(17;17), 1 with +8, and 1 with add (7)(q22); -7; +8). According to many studies, leukemic cell heterogeneity in APL influences the clinical outcome of disease. The analysis of certain leukemic cell characteristics on the clinical outcome in our study revealed that patients with bcr3 had shorter medians of first remission and survival in comparison to patients with the bcr1 isoform of PML/RARalpha. Also, the clinical relapse of disease in 4 APL patients with reverted PML/RAR alpha positivity is consistent with the view that detection of PML/RARalpha by RT-RCR in patients in remission implies a poor prognosis. On the contrary, lack of detection of PML/RARalpha by RT-PCR at least three times is a sign of long remission and survival.

Biology and outcome of childhood acute megakaryoblastic leukemia: a single institution's experience

To describe the clinical and biologic features of pediatric acute megakaryoblastic leukemia (AMKL) and to identify prognostic factors, experience at St Jude Children's Research Hospital was reviewed. Of 281 patients with acute myeloid leukemia treated over a 14-year period, 41 (14.6%) had a diagnosis of AMKL. Six patients had Down syndrome and AMKL, 6 had secondary AMKL, and 29 had de novo AMKL. The median age of the 22 boys and 19 girls was 23.9 months (range, 6.7-208.9 months). The rate of remission induction was 60.5%, with a 48% rate of subsequent relapse. Patients with Down syndrome had a significantly higher 2-year event-free survival (EFS) estimate (83%) than did other patients with de novo AMKL (14%) or with secondary AMKL (20%; P < or =.038). Among patients who had de novo AMKL without Down syndrome, 2-year EFS was significantly higher after allogeneic bone marrow transplantation (26%) than after chemotherapy alone (0%; P =.019) and significantly higher when performed during remission (46%) than when performed during persistent disease (0%; P =.019). The 5-year survival estimates were significantly lower for de novo AMKL (10%) than for other forms of de novo AML (42%; P <.001). Treatment outcome is very poor for patients with AMKL in the absence of Down syndrome. Remission induction is the most important prognostic factor. Allogeneic transplantation during remission offers the best chance of cure; in the absence of remission, transplantation offers no advantage over chemotherapy alone. (Blood. 2001;97:3727-3732)

Treatment of childhood acute myelogenous leukemia with an intensive regimen (AML-87) that individualizes etoposide and cytarabine dosages: short- and long-term effects

The purpose of this study was to assess the feasibility and efficacy of a treatment regimen for pediatric acute myelogenous leukemia (AML) that uses four rotating drug pairs and adjusts dosages of etoposide and cytarabine to target specific plasma concentrations. Thirty-one girls and 27 boys (median age, 9.7 years) with de novo AML were treated on the protocol. Six cycles of chemotherapy were planned. Cycles 1 to 4 comprised the drug combinations cytarabine plus etoposide, cytarabine plus daunomycin, etoposide plus amsacrine, and etoposide plus azacitidine, respectively. For cycles 5 and 6, the first two combinations were repeated. Dosages were adjusted to achieve plasma concentrations of 1.0 microM +/- 0.1 microM cytarabine and 30 microM +/- 0.3 microM etoposide. Forty-four patients (76%) entered complete remission. Of those, 24 have had relapses; 23 remain alive in first or subsequent remission. The 5-year event-free survival (EFS) estimate was 31.0% +/- 5.9%; the 5-year survival estimate was 41.4% +/- 6.3%. Six patients (10%) died of the toxic effects of therapy. Severe neutropenia occurred in all cycles. Long-term complications of therapy included hepatitis C, cardiac insufficiency, and hearing loss. Adjustment of cytarabine and etoposide dosage was feasible for achieving targeted plasma drug concentrations; however, the potential clinical efficacy of this approach was offset by substantial acute and long-term toxicity.