Good outcome of children with acute myeloid leukemia and t(8;21)(q22;q22), even when associated with granulocytic sarcoma

Clinical Characteristics and Treatment Outcomes of Myeloid Sarcoma in Children: The Experience of the Polish Pediatric Leukemia and Lymphoma Study Group

Introduction

Myeloid sarcoma (MS) is an extramedullary malignant tumor composed of immature myeloid cells. It occurs in patients with acute myeloid leukemia (AML), myelodysplastic syndrome (MDS), or chronic myeloid leukemia (CML). MS may coincide with disease diagnosis or precede bone marrow involvement by months or even years; it can also represent the extramedullary manifestation of a relapse (1, 2).

Aim

The aim of this study is to describe clinical characteristics of children diagnosed with MS in Poland as well as to analyze diagnostic methods, treatment, and outcomes including overall survival (OS), relapse-free survival (RFS), and event-free survival (EFS). The study also attempted to identify factors determining treatment outcomes.

Patients

The study group comprised 43 patients (F=18, M=25) aged 0-18 years (median age, 10.0 years; mean age, 8.8 years) diagnosed with MS based on tumor biopsy and immunohistochemistry or identification of underlying bone marrow disease and extramedullary tumor according to imaging findings.

Methods

The clinical data and diagnostic and therapeutic methods used in the study group were analyzed. A statistical analysis of the treatment outcomes was conducted with STATISTICA v. 13 (StatSoft, Inc., Tulsa, OK, USA) and analysis of survival curves was conducted with MedCalc 11.5.1 (MedCalc Software, Ostend, Belgium). Statistical significance was considered at p<0.05.

Results

In the study group, MS was most frequently accompanied by AML. The most common site of involvement was skin, followed by orbital region. Skin manifestation of MS was more common in the age group <10 years. The most frequent genetic abnormality was the t(8;21)(q22;q22) translocation. The 5-year OS probability (pOS), 5-year RFS probability (pRFS), and 5-year EFS probability (pEFS) were 0.67 ± 0.08, 0.79 ± 0.07, and 0.65 ± 0.08, respectively. In patients with isolated MS and those with concurrent bone marrow involvement by AML/MDS, pOS values were 0.56 ± 0.12 and 0.84 ± 0.09 (p=0.0251), respectively, and pEFS values were 0.56 ± 0.12 and 0.82 ± 0.08 (p=0.0247), respectively. In patients with and without the t(8;21)(q22;q22) translocation, pEFS values were 0.90 ± 0.09 and 0.51 ± 0.14 (p=0.0490), respectively.

Conclusions

MS is a disease with a highly variable clinical course. Worse treatment outcomes were observed in patients with isolated MS compared to those with concurrent bone marrow involvement by AML/MDS. Patients with the t(8;21)(q22;q22) translocation were found to have significantly higher pEFS. MS location, age group, chemotherapy regimen, surgery, and/or radiotherapy did not have a significant influence on treatment outcomes. Further exploration of prognostic factors in children with MS is indicated.

Myeloid sarcoma is associated with poor clinical outcome in pediatric patients with acute myeloid leukemia

PURPOSE

The impact of myeloid sarcoma (MS) on clinical outcome of pediatric acute myeloid leukemia (AML) patients remains controversial. Moreover, little is known about the role of stem cell transplantation (SCT) in such patients.

METHODS

Clinical data of patients with AML under 18 years of age were retrieved from the TARGET dataset. We analyzed the prevalence, clinical profile, molecular characteristics, and prognosis of MS in these patients.

RESULTS

Among 884 pediatric patients with AML, the frequency of MS was 12.3%. Pediatric AML with MS was associated with age under 1-year, abnormal cytogenetics, and KMT2A rearrangement. Moreover, MS was associated with a low complete remission rate, high induction death, poor 5-year EFS, and OS. KMT2A rearrangement had a negative impact on clinical outcome in AML patients with MS. In addition, SCT had no significant effect on the survival of AML patients with MS. Multivariate analysis revealed that MS was an unfavorable prognostic factor in pediatric AML in terms of EFS (Hazard ratio 1.670, P < 0.001) and OS (Hazard ratio 1.623, P = 0.004).

CONCLUSIONS

The presence of MS at diagnosis of pediatric AML is associated with poor clinical outcomes, particularly when associated with KMT2A rearrangements. Moreover, pediatric patients with AML and MS may not benefit from SCT.

Clinical characteristics, molecular profile and outcomes of myeloid sarcoma: a single institution experience over 13 years

BACKGROUND

Myeloid sarcoma (MS) is characterized by extramedullary infiltration by immature myeloid cells. Owing to rarity of this disease, the clinical features and overall outcomes are yet to be clarified.

OBJECTIVE

To define clinical characteristics, epidemiology, pathologic findings, treatment options and outcomes in MS.

METHODS

We conducted a retrospective review of 23 patients diagnosed with MS at our institute over a period of 13 years (2002-2015).

RESULTS

MS presented mostly as a manifestation of relapsed acute myeloid leukemia, seen in 39% of patients. Skin and subcutaneous soft tissues were the most common sites of anatomic involvement (69.5%). Ninety five percent (n = 19) were positive for classical myeloid markers with either cytochemical staining (chloracetate-esterase, MPO), flow-cytometry (CD33, CD34, CD13 and CD117), or immunohistochemistry (CD34, CD43, CD68 and lysozyme). Of these, 52% were positive for CD33 (n = 12), 35% for CD68 (n = 8), 30% for CD34 (n = 7), and 26% for lysozyme (n = 6). Cytogenetic abnormalities were seen in 63% (n = 12/19) patients on bone-marrow aspirate, with five patients displaying a complex (n = 3) or monosomal (n = 2) karyotype. Twenty seven percent patients with a normal karyotype had presence of deleterious mutations (FLT3, ASXL, STAG and JAK2) on further testing with myeloid mutation panel. The Median overall survival (OS) of the entire cohort was 15.9 months (95% CI, 7.4-24.4 months). The OS was significantly better for patients <65 years (24.6 vs. 3.4 months, p = 0.009) of age, and for those attaining a complete remission (CR) to induction therapy (25.7 vs. 0.8 months, p < 0.001). All patients who underwent allogeneic hematopoietic stem cell transplant attained long-term remissions, with a median follow-up of 54 (range 32-120) months.

CONCLUSION

Failure to achieve CR with induction therapy, and age >65 years are associated with poor outcomes in MS. Allogeneic stem-cell transplant in first remission appears to be the most effective modality for achieving long-term remissions.

Characteristics and Survival Outcome Analysis of Extramedullary Involvement in Adult Patients With t(8;21) Acute Myeloid Leukemia

BACKGROUND

Acute myeloid leukemia (AML) with t(8;21)(q22;q22) is classified into a favorable-risk group. Extramedullary (EM) involvement has frequently been reported in this subgroup as resulting in a poor prognosis. However, characteristics or standard treatments of t(8;21) AML with EM involvement (EM-positive t(8;21)) have not yet been elucidated.

PATIENTS AND METHODS

We retrospectively analyzed 154 adult AML patients with t(8;21). Among them, 17 were EM positive and 137 were EM negative at the time of diagnosis. EM involvement was evaluated only when a patient showed suspicious signs or symptoms. All EM-positive patients were treated according to a strategy based on allogeneic hematopoietic cell transplantation (allo-HCT).

RESULTS

Central nervous system was the most frequently involved site (70.6%). EM-positive t(8;21) was associated with age ≤ 45 years, leukocytosis (≥ 30 × 10⁹/L), and c-kit mutation compared to EM-negative t(8;21) in multivariate analysis. After intensive chemotherapy with or without local therapy, high-risk t(8;21) AML including EM-positive t(8;21) underwent allo-HCT for postremission therapy. Three-year OS (52.3% vs. 60.0%, P = .658) and event-free survival (51.5% vs. 58.0%, P = .496) were not different between the 2 groups. The subgroup of patients who underwent allo-HCT also showed similar outcomes.

CONCLUSION

EM-positive t(8;21) was associated with young age, leukocytosis, and c-kit mutation, and central nervous system was frequently involved. Allo-HCT resulted in good outcomes in EM-positive t(8;21).

Extramedullary Manifestations of Myeloid Neoplasms

OBJECTIVES

This session of the 2013 Society of Hematopathology/European Association for Haematopathology workshop focused on extramedullary manifestations of myeloid neoplasms.

METHODS

We divided the submitted cases into four subgroups: (1) isolated myeloid sarcoma (MS); (2) MS with concurrent acute myeloid leukemia (AML), with a focus on karyotypic and molecular findings; (3) extramedullary relapse of AML, including relapse in the posttransplant setting; and (4) blast phase/transformation of a myeloproliferative neoplasm or chronic myelomonocytic leukemia.

RESULTS

Establishing a diagnosis of isolated MS requires a high index of suspicion and use of immunophenotypic methods. Recurrent cytogenetic abnormalities or gene mutations that occur in MS mirror those known to occur in AML.

CONCLUSIONS

In the era of targeted therapy and sophisticated risk stratification, every attempt must be made to perform a complete workup on MS cases (or concurrent AML) since the diagnosis of MS, in itself, is no longer adequate for patient management. Cases of blastic plasmacytoid dendritic cell neoplasm were also included and discussed in this session.

The paradox of recurrent with rare: A rare case of bilateral proptosis and facial palsy in acute myeloid leukemia with recurrent cytogenetic translocation t(8:21)

A 13-year-old female child presented with bilateral proptosis and subconjuctival hemorrhage of 2 months duration. Subsequently, the biopsy and peripheral smears confirmed the diagnosis of acute myeloid leukemia (AML). Recurrent cytogenetic translocation t(8:21) in AML associated with extramedullary manifestation; was discovered which is a rare event. Furthermore, myeloperoxidase negative blasts and periodic acid Schiff negative blasts in AML with t(8:21) is a very rare combination to the best of our knowledge.

Disseminated myeloid sarcomas-a rare presentation of acute myeloid leukemia

Acute Myeloid Leukemias (AML) may present rarely as anatomical distortions at extramedullary sites, termed as Myeloid Sarcomas (MS). Though MS can involve different sites, concomitant involvement of multiple sites is very rare. Here, we describe an adolescent girl who presented with disseminated MS at multiple sites. Such a presentation of AML has not been described before. The delay in presentation of the patient to a proper medical center is also to be noted here.

Is acute myeloid leukemia a liquid tumor?

Extramedullary manifestations of acute myeloid leukemia (AML) were described as early as the 19th century. However, the incidence, clinical significance and pathobiology of extramedullary AML remain ill defined. We reviewed case reports, retrospective case series, pilot studies and imaging studies of extramedullary leukemia (EML) to determine its frequency, characteristics, clinical presentation and significance. EML precedes or accompanies development of AML and occurs during or following treatment, even during remission. Although imaging studies are rarely conducted and the true incidence of EML has yet to be verified, authors have reported several estimates based on retrospective and autopsy studies. The incidence of EML in patients with AML of all ages is estimated to be about 9% and EML in children with AML was detected in 40% of patients at diagnosis. The combination of positron emission tomography and computed tomography were the most sensitive and reliable techniques of detecting and monitoring EML. Based on our literature review, the frequency of EML is likely underreported. The well-documented nature of EML in patients with AML suggests that AML can manifest as a solid tumor. The extent to which EML accompanies AML and whether EML is derived from bone marrow are unknown. Furthermore, questions remain regarding the role of the microenvironment, which may or may not facilitate the survival and proliferation of EML, and the implications of these interactions with regard to minimal residual disease, tumor cell quiescence and relapse. Therefore, prospective studies of detection and characterization of EML in patients with AML are warranted.

Diagnosis and management of acute myeloid leukemia in children and adolescents: recommendations from an international expert panel

Despite major improvements in outcome over the past decades, acute myeloid leukemia (AML) remains a life-threatening malignancy in children, with current survival rates of ∼70%. State-of-the-art recommendations in adult AML have recently been published in this journal by Döhner et al. The primary goal of an international expert panel of the International BFM Study Group AML Committee was to set standards for the management, diagnosis, response assessment, and treatment in childhood AML. This paper aims to discuss differences between childhood and adult AML, and to highlight recommendations that are specific to children. The particular relevance of new diagnostic and prognostic molecular markers in pediatric AML is presented. The general management of pediatric AML, the management of specific pediatric AML cohorts (such as infants) or subtypes of the disease occurring in children (such as Down syndrome related AML), as well as new therapeutic approaches, and the role of supportive care are discussed.

Clinical significance of granulocytic sarcoma in adult patients with acute myeloid leukemia

To investigate the clinical significance of granulocytic sarcoma (GS) in adults with acute myeloid leukemia (AML), 434 consecutive patients with AML were analyzed retrospectively. Forty-five patients (10.4%) with GS at diagnosis were younger (P < 0.001), presented with higher white blood cell counts (P = 0.03) and were more likely to conform to French-American-British M4 (P = 0.001) and M5 (P = 0.045) classifications than those without GS. In contrast, no significant difference in frequency of cytogenetic abnormalities was found between the GS and non-GS groups. Treatment outcomes in 260 patients (40 with GS) who underwent intensive chemotherapy, excluding patients with acute promyelocytic leukemia, were investigated. Complete remission rates did not differ significantly between the GS and non-GS groups (75.0% vs 79.1%; P = 0.192, respectively) or the 5-year overall survival (OS) rates (39.9% vs 38.7%; P = 0.749, respectively). However, the GS group had a significantly higher relapse rate than the non-GS group (74.2% vs 55.3%; P = 0.048) and a significantly lower 5-year disease-free survival rate (8.2% vs 25.7%, respectively; P = 0.005). When considered together with the results of multivariate analysis, which identified the presence of GS as an independent predictor for disease-free survival time, these findings indicate that GS might identify a high-risk subset of patients with AML.

Superior outcome of pediatric acute myeloid leukemia patients with orbital and CNS myeloid sarcoma: a report from the Children's Oncology Group

BACKGROUND

Extramedullary leukemia (EML) is common in pediatric acute myeloid leukemia (AML) and occurs as leukemia cells within the cerebrospinal fluid (CSF) or as a solid tumor (myeloid sarcoma-MS). The effect of MS on survival is unknown.

METHODS

Patients on CCG protocols 2861, 2891, 2941, and 2961 being treated for AML with intensive-timing chemotherapy were classified for the presence of EML (CSF leukemia, CNS-MS, orbital-MS, or non-CNS MS). CSF leukemia was classified as CNS3 (>5 WBC in the CSF with blasts) and non-CSF leukemia as CNS1/2 (<5 WBC in the CSF with or without blasts). Characteristics and outcomes of these patients were compared.

RESULTS

Of the 1,459 total patients, 1,206 (82%) had no EML, 154 (11%) had CSF leukemia, 19 (1%) had CNS-MS, 23 (2%) had orbital-MS, and 57 (4%) had non-CNS MS. The CR rate was significantly higher in patients with orbital-MS and CNS-MS than in those with non-MS and non-CNS MS (96% and 95% vs. 78% and 78%, P = 0.034). Patients with orbital-MS and CNS-MS had significantly higher overall survival than patients with non-CNS MS (92% and 73% vs. 38%, P < 0.001), CNS3 patients (92% and 73% vs. 51, P < 0.001), and CNS1/2 patients (92% and 73% vs. 50%, P < 0.001). Patients with orbital-MS had a significantly lower relapse rate.

CONCLUSION

Patients with MS involving orbital and CNS sites had a significantly better survival than patients with non-CNS MS, with CSF leukemia, or with no EML.

Acute myeloid leukemia with the t(8;21) translocation: clinical consequences and biological implications

The t(8;21) abnormality occurs in a minority of acute myeloid leukemia (AML) patients. The translocation results in an in-frame fusion of two genes, resulting in a fusion protein of one N-terminal domain from the AML1 gene and four C-terminal domains from the ETO gene. This protein has multiple effects on the regulation of the proliferation, the differentiation, and the viability of leukemic cells. The translocation can be detected as the only genetic abnormality or as part of more complex abnormalities. If t(8;21) is detected in a patient with bone marrow pathology, the diagnosis AML can be made based on this abnormality alone. t(8;21) is usually associated with a good prognosis. Whether the detection of the fusion gene can be used for evaluation of minimal residual disease and risk of leukemia relapse remains to be clarified. To conclude, detection of t(8;21) is essential for optimal handling of these patients as it has both diagnostic, prognostic, and therapeutic implications.

Ovarian Granulocytic Sarcoma

Granulocytic sarcoma (GS) or chloroma is a neoplasia of immature myeloid cells. Bones, skins, soft tissues and lymph nodes are the most frequently involved organs with this entity and not infrequently it is diagnosed histopathologically as non-Hodgkin's lymphoma (NHL). Ovarian granulocytic sarcoma is a rare entity in daily practice. Here we report an ovarian granulocytic sarcoma, initially diagnosed as NHL, and review the literature.

Cytogenetic, morphological, and immunophenotypic patterns in Omani patients with de novo acute myeloid leukemia

Chromosome aberrations observed at diagnosis are considered to be the most valuable prognostic factors in acute myeloid leukemia (AML). Some specific aberrations vary in frequency among different geographical areas and ethnic groups. There are only limited studies on the role of such variability in AML patients. Here, we report the results of a cytogenetic study on 63 ethnic Omani patients with de novo AML: 18 children (<or=16 years) and 45 adults. By sex, 41 were male and 22 female; median age at diagnosis was 25 years. The morphological diagnosis was based on the French-American-British (FAB) WHO criteria. Chromosome abnormalities were present in 39 of 63 patients (62% overall, or 44% for adults and 18% for children). Karyotypes with a sole abnormality accounted for 20 of 63 patients (32%). Chromosome abnormalities were more common in patients with the FAB-M2 subtype (15 of 22; 68%), which was also the most frequent subtype observed (22 of 63; 35%). Among the normal karyotypes (24 of 63; 38%), M2 subtype was the also most frequent (7 of 24; 29%), followed by M4 (4 of 24; 17%). Balanced translocations, t(8;21) and t(15;17) were observed in 7 of 63 (11%) and 6 of 63 (10%), respectively. Inv(16) was seen in 2 of 63 (3%). Trisomy 8 was the most frequent numerical anomaly, found in 7 of 63 (11%). Monosomy 7 was seen in 3 of 63 (5%). The patterns in our study were similar to those reported from Saudi Arabia and Kuwait, but the frequency of abnormalities varied. Our population differed morphologically, with the M2 subtype as most common, whereas M4 and M3 were more commonly in those reports. A comparison of our findings was made with other geographic and ethnic groups. This is the first systematic cytogenetic study of an ethnic Omani population.

Prognosis and treatment outcome in patients with acute myeloid leukemia with t(8;21)(q22;q22)

Patients with acute myeloid leukemia (AML) with the t(8;21) karyotype generally have a favorable clinical course, but key prognostic factors remain poorly defined. This study was conducted to determine the prognoses and treatment outcomes of patients with AML with this unique cytogenetic change. A total of 22 patients with AML with t(8;21)(q22;q22) were studied. Various parameters were tested for their impact on disease-free survival (DFS) and overall survival (OS). Another 55 patients with AML with a normal karyotype were included for comparison of clinical outcomes. Between patients with t(8-21) and those with a normal karyotype, no significant differences were noted in DFS (median survival, 15.23 vs 12.03 mo; P=.7626) and OS (median survival, 19.17 vs 18.93 mo; P=.7543). Among t(8;21)(q22;q22) patients, no clinical parameters showed a significant impact on DFS. Univariate analysis revealed that a higher platelet count (>15.10(9)/L) at diagnosis, a low white blood cell count (index < or =20), and hematopoietic stem cell transplantation (HSCT) as postremission therapy were associated with improved OS. On multivariate analysis, HSCT as postremission therapy and white blood cell count index <20 remained good independent prognostic factors for OS. The data presented here suggest that t(8;21)(q22;q22) cytogenetic changes in patients with AML had prognostic significance similar to that in patients with a normal karyotype; patients who harbored either karyotype had parallel clinical outcomes. It is concluded that patients with AML with t(8;21)(q22;q22) would be compromised by treatment approaches that do not include HSCT as postremission therapy.

Clinical and imaging characteristics of orbital leukemic tumors

PURPOSE

To characterize the clinical and imaging features of orbital leukemic tumors in 27 patients seen and treated at St. Jude Children's Research Hospital.

METHODS

A retrospective review was performed on the clinical and imaging records of 27 consecutive patients with a diagnosis of orbital leukemic tumors. The following data were extracted from the patients' records: age at diagnosis of orbital leukemic tumors, sex, race, national origin, type of leukemia, temporal relationship of orbital disease to diagnosis of leukemia, survival from diagnosis of orbital leukemic tumor, laterality of the orbital disease, location of the mass within the orbit, imaging features of the mass, chemotherapeutic protocol, treatment with bone marrow transplant, and orbital radiation.

RESULTS

The median age at diagnosis of orbital leukemic tumor was 8 years (range, 1-18 years). Nineteen of the 27 patients were male, and 21 patients were born and lived in the United States. Twenty-one patients had acute myeloid leukemia, five had acute lymphoblastic leukemia, and one had chronic myelogenous leukemia. In 85% of patients (n = 23), the diagnosis of leukemia was based on the bone marrow examination findings. Orbital imaging revealed homogenous masses that molded to one or more orbital walls without bony destruction. Nine patients had bilateral orbital involvement. All patients received multiagent systemic chemotherapy, and 14 underwent bone marrow transplantation. Five patients received external beam radiation for the treatment of orbital disease. Fifteen (55.6%) of the 27 patients were alive at the time of the study. The median survival for all patients was 4.75 years (range, 0.1-24 years) after the diagnosis of orbital disease.

CONCLUSIONS

Orbital leukemic tumors occur most commonly in the first decade of life, in association with acute myeloid leukemia. They appear as homogenous masses along the orbital walls. Although the overall survival rate for patients with leukemia has improved over the past 3 decades, the mortality of patients who develop orbital leukemic tumors remains high.

Cytogenetic and morphological findings in 166 patients with de novo acute myeloid leukemia in southern Brazil

Chromosomal rearrangements correlate with different clinical subgroups of blood disorders. Some of these chromosomal abnormalities are found in individuals from specific geographical areas and ethnic groups. A high incidence of t(15;17) translocation has been observed, for example, in the Hispanic populations of the United States and Spain. The same occurs in South America, due to the rich diversity of ethnic groups that colonized the region. We performed a cytogenetic analysis of 166 patients at the Division of Hematology of Hospital de Clínicas de Porto Alegre between 1990 and 2002. Those patients who met the criteria for de novo acute myeloid leukemia (AML) and whose karyotypes could be successfully determined were included in the study. The karyotypes of each patient and the French-American-British (FAB) criteria for the diagnosis of AML were reviewed. Chromosomal abnormalities were identified and classified according to ISCN 1995. Chromosomal abnormalities were found in 53.6% of cases. Abnormalities were significantly more common in the FAB-M3 group (70.3%). The most common balanced translocation was t(15;17), observed in 13.25% of the patients.

Myeloid sarcoma with multiple lesions of the central nervous system in a patient without leukemia

✓ The authors report the unusual case of a 35-year-old woman suffering from left leg numbness and radiculopathy due to multiple lesions in the central nervous system: one right parietal extracranial–intracranial lesion with invasion of the sensory cortex, and two intraspinal, intradural lesions compressing the spinal cord at T3–5 and S1–4. Biopsy sampling of the extracranial part of the parietal lesion led to a diagnosis of myeloid sarcoma. Further examination revealed no evidence of leukemic disease or myeloproliferative disorder. An aggressive multimodal approach to treatment in this patient with a combination of chemotherapy, whole-body radiotherapy, and allogeneic bone marrow transplantation was started immediately. The patient experienced full neurological recovery and complete disappearance of all lesions. At the 7-year follow-up examination, there was no evidence of disease. To the authors’ knowledge, this is the first report of a myeloid sarcoma with both intracranial and intraspinal manifestations in a patient without leukemia.

Meningeal tumors of childhood and infancy. An update and literature review

Meningeal derived tumors of the first 2 decades of life are often diagnostically challenging due to the wide morphologic spectrum encountered and the rarity of most individual entities. The 2 most common patterns include the dural/leptomeningeal-based mass and neoplastic meningitis. Both primary and secondary meningeal presentations may occur, either early or late in the course of various meningothelial, mesenchymal, embryonal, glial, hematopoietic, histiocytic, melanocytic, and inflammatory tumors. As in other areas of pediatric pathology, there are significant differences between this patient cohort and adults, differences which will be emphasized in this review.

Granulocytic sarcoma presenting as pneumonia in a child with t(8;21) acute myelogenous leukemia: diagnosis by fluorescent in situ hybridization

Granulocytic sarcoma is a soft tissue collection of leukemic cells. The authors describe a 4-year-old boy with M2 acute myelogenous leukemia (AML) who presented with fever, mild nonproductive cough, and hematemesis. Although he was initially diagnosed with nodular pneumonia, rapid resolution of a pulmonary infiltrate following induction chemotherapy was suggestive of a pulmonary granulocytic sarcoma. Interphase fluorescent in situ hybridization (FISH) of the lung biopsy specimen for the t(8;21)(q22;q22) translocation confirmed the retrospective diagnosis of a well-differentiated pulmonary granulocytic sarcoma. Pulmonary granulocytic sarcomas may be underrecognized in children with AML; this may delay anti-leukemic therapy and may lead to ineffective therapy if misdiagnosed as pneumonia.

Classical and molecular cytogenetic abnormalities and outcome of childhood acute myeloid leukaemia: report from a referral centre in Israel

The incidence of cytogenetic abnormalities in childhood de novo acute myeloid leukaemia (AML) and its prognostic significance was assessed in an Israeli paediatric referral centre. Cytogenetic analysis was successful in 86 of 97 children (< 20 years of age) diagnosed between 1988 and 2002 with de novo AML. Fluorescence in situ hybridization analysis detected new information in 11 of them, leading to reassignment in cytogenetic group classification. The incidence of the various cytogenetic subgroups was as follows: normal - 9%; t(11q23) - 22%; t(8;21) - 13%; t(15;17) - 8%; inv(16) - 3.4%; abn(3q) - 4.6%; 7/7q-(sole or main) - 5.8%; del(9q)(sole) and +21(sole) - 4.6% each; t(8;16) - 2.3%; t(6;9), t(1;22), +8(sole) - 1.1% each; and miscellaneous - 18%. The overall survival (OS) and event-free survival (EFS) (4 years) for 94 patients treated with the modified Berlin-Frankfürt-Münster (BFM) AML protocols (non-irradiated) were 59.9% (SE = 5%) and 55.7% (SE = 5%), respectively, and for the favourable t(8;21), t(15;17) and inv(16), OS was 60% (SE = 15%), 83% (SE = 15%) and 100% respectively. For the normal group it was 62% (SE = 17%), miscellaneous 64% (SE = 12%), t(11q23) 44.6% (SE = 11%) and of the -7/7q-, del(9q)(sole) or t(6;9), none had survived at 4 years. The incidence of cytogenetic subgroups in the Israeli childhood AML population and their outcome were similar to other recently reported paediatric series. Cytogenetic abnormalities still carry clinical relevance for treatment stratification in the context of modern chemotherapy.

Characteristics and outcome of t(8;21)-positive childhood acute myeloid leukemia: a single institution's experience

To elucidate the clinical and biological features of childhood acute myeloid leukemia (AML) with the t(8;21), we reviewed the records of patients with AML treated at St Jude Children's Research Hospital over a 17-year period (1980 to 1996). Of 298 patients with AML, 40 (13%) had blast cells that contained the t(8;21). This translocation was associated with a high frequency of French-American-British M2 morphology (82%) and the presence of granulocytic sarcoma (23%). Molecular analysis detected the AML1-ETO fusion transcript in all 25 cases with the t(8;21) tested, but failed to identify additional cases with AML1-ETO among the 127 cases with other cytogenetic findings. Compared to patients with other genetic abnormalities, those with the t(8;21) were less likely to have internal tandem duplications of the FLT3 gene (none of 10 vs 16 of 68). The 6-year overall survival estimate was 55% +/- 9% and the event-free survival estimate, 33% +/- 7%. Of the clinical and biological features examined, only gender was prognostically significant: the 6-year overall survival estimate for males was 68% +/- 10%, compared to 33% +/- 11 for female patients (P = 0.03). Treatment outcome was not influenced by the chemotherapy regimen used or by the use of autologous hematopoietic stem cell transplantation. These results suggest that t(8;21)-positive AML represents a heterogeneous disease with variable outcome. The reported favorable outcome for t(8;21)-positive AML in other studies may be due to the use of high-dose cytarabine.

Isolated extramedullary relapse in the pleural fluid of a patient with acute myeloid leukemia following allogeneic BMT

We report an unusual case of AML, in which the patient showed extramedullary relapse in the pleural fluid and the skin without bone marrow recurrence even 3 years after allogeneic BMT. On examination of the pleural effusion and the skin, which relapsed 31 months and 40 months, respectively, after BMT, we found that most of cells were as the XY-type recipient by quantitative X/Y FISH (fluorescence in situ hybridization). However, 100% of the bone marrow cells remained XX-type donor cells. In the present case, we believe that the graft-versus-leukemia (GVL) response in the extramedullary site was not so effective as that in the bone marrow, where it remains effective.

Isolated myelosarcoma in children--update and review

Primary myelosarcomas, also called leukemia cutis, granulocytic sarcomas or chloromas, are rare extramedullary manifestations of acute myeloid leukemia (AML) which precede bone marrow involvement. Skin infiltration was the most frequent localization associated with a myelomonocytic differentiation. Although first remission was achieved by most children, risk of relapse seemed to be increased. This might be caused by the specific biology of myelosarcomas, but also may be the result of delayed or reduced treatment. During the AML-BFM-studies 87/93/98 (11/1987-7/2000) 37 children with isolated myelosarcomas were diagnosed. Eighteen of the 37 patients survived with a 5-year overall survival estimation of 0.54+/-0.09 compared to 0.59+/-0.02; p(log rank) = 0.94. However, reduced or delayed treatment in 17 children led to an increased relapse rate of 71% compared to 35% in children treated soon after diagnosis. The 5-year overall survival in these patients was 0.41+/-0.11. According to our experience and review of the literature, an early diagnostic workup is needed in children with unusual skin lesions or tumors, considering myelosarcoma as primary manifestation of AML. Intensive AML-specific chemotherapy is generally recommended soon after diagnosis.

Aleukemic granulocytic sarcoma with AML1/ETO fusion gene expression and clonal T cell populations

We report a unique case of aleukemic granulocytic sarcoma of the neck, originally misdiagnosed as non-Hodgkin's lymphoma (NHL), though chloroma was also suspected due to a greenish macroscopic appearance and the presence of myeloid chloroacetate esterase (CAE)+ cells. The proof of clonal T cell receptor gamma chain (TcRgamma) gene rearrangements in the recurring tumor was deemed to confirm the initial diagnosis of T cell NHL. Altogether five distinct types of clonal TcRgamma gene rearrangements were found in the tumor, bone marrow and peripheral blood. Only retrospectively, using RT-PCR, did we detect the acute myeloid leukemia subset-specific fusion gene AML1/ETO in the frozen samples of the relapsed tumor, as well as in the otherwise unaffected bone marrow and peripheral blood (representing 'minimal initial disease' in the latter two samples). Simultaneous staining verified that the neoplastic CAE+ cells and CD45RO+ T cells were different populations.

Clinical importance of cytogenetics in acute myeloid leukaemia

Acquired chromosome aberrations are present in the marrow of most patients with acute myeloid leukaemia (AML) at diagnosis. Cytogenetically, AML is a very heterogeneous disease with over 160 structural chromosome abnormalities observed recurrently to date. Molecular dissection of many reciprocal translocations and inversions has resulted in cloning of the genes involved in leukaemogenesis. Some recurrent aberrations and the resulting gene rearrangements, namely inv(16)/t(16;16) and CBFbeta- MYH11, t(8;21) and CBFA2-CBFA2T1, t(15;17) and PML-RARalpha, and rearrangements of band 11q23 and the MLL gene, are now used to help define distinct disease entities within AML in the new World Health Organization classification of haematological malignancies. Moreover, cytogenetic abnormalities, whether molecularly characterized or not, are among the most important, independent prognostic factors in AML, and are being used in the management of AML patients. This review presents current information on chromosome abnormalities in AML, and on associations between karyotype and clinical characteristics and outcome of AML patients.