Extramedullary infiltration at diagnosis and prognosis in children with acute myelogenous leukemia

Extramedullary Tumor of Cerebral Falx: An Unusual Presentation of Acute Megakaryocytic Leukemia

In childhood acute myelogenous leukemia, extramedullary tumor is an occasional clinical symptom. However, extramedullary acute megakaryocytic leukemia is extremely rare. Here, we report an extremely rare case of acute megakaryocytic leukemia in a patient who presented with extramedullary tumor of cerebral falx as a first manifestation before the diagnosis of systemic bone marrow leukemia.

Myeloid sarcoma: a rare case of an orbital mass mimicking orbital pseudotumor requiring neurosurgical intervention

Objective. A rare case of myeloid sarcoma (MS), previously referred to as granulocytic sarcoma or chloroma, is presented. Representing a unique form of acute myeloid leukemia (AML), MS may rarely occur in adults. Even rarer, MS may occur as the initial presentation of AML. Methods. We report a singular and illustrative case of an orbital pseudotumor mimicking mass in a 65-year-old male as the initial presentation of AML. Results. Neurosurgical intervention was required to establish the definitive diagnosis via right modified orbitofrontozygomatic craniotomy as well as to decompress the optic canal, superior orbital fissure, and orbit. Conclusion. Postoperatively, he reported decreased pain and improvement of his vision. Further examination revealed decreased proptosis and improved extraocular mobility. Pathological findings demonstrated MS. We review the literature and discuss the neurosurgical relevance of MS as the initial presentation of AML.

Facial palsy as an unusual presenting symptom associated with acute myeloid leukemia

Extramedullary infiltration is common in acute myeloid leukemia (AML) patients. Although AML can cause neurological symptoms, especially when associated with extramedullary infiltration, a presenting manifestation of facial palsy is rare. We report on a 1-year-old boy who developed right facial palsy. Detailed examination led to a diagnosis of AML (French-American-British classification M1). Magnetic resonance imaging enhanced with gadolinium-diethylenetriamine penta-acetic acid showed abnormal enhancement of the right facial nerve, which disappeared after chemotherapy. AML should be considered as a differential diagnosis of facial palsy. Enhanced magnetic resonance imaging may be useful for diagnosing facial palsy associated with AML and for evaluating treatment outcome.

Establishment of NOD/SCID mouse model of central nervous system leukemia

In the present study, we successfully established a NOD/SCID mouse model of central nervous system leukemia by injection of acute monocytic leukemia cell line SHI-1 cells into the lateral ventricle. Immunohistochemistry was used to detect human leukocyte common antigen in brain slices. Nested PCR assay was used to detect MLL/AF6 fusion gene expression. After injection, the condition of the mice gradually progressed to cachexia and death (median survival time, 25 days). Leukemic cells were identified in the lung, bone marrow, and lymph node of one mouse. Brain tissue sections showed invasion into the subdural space, pia mater, arachnoid, along the Virchow-Robin space and into the deep brain parenchyma. In summary, a central nervous system leukemia (CNSL) model was established in NOD/SCID mice.

Overview of therapy and strategies for optimizing outcomes in de novo pediatric acute myeloid leukemia

Although acute myelogenous leukemia (AML) accounts for <20 % of leukemia in children, it is responsible for over half of all pediatric leukemia deaths. Improvement in event-free survival rates, now over 50 %, are due largely to intensification of chemotherapy, aggressive supportive care, development of risk stratification based on cytogenetic and molecular markers, and improved salvage regimens. Despite this improvement over the past few decades, the survival rates have recently plateaued, and further improvement will need to take into account advances in molecular characterization of AML, development of novel agents, and better understanding of host factors influencing toxicity and response to chemotherapy. This article reviews the epidemiology and biology trends in diagnosis and treatment of pediatric acute myelogenous leukemia.

WT1 mutation in pediatric patients with acute myeloid leukemia: a report from the Japanese Childhood AML Cooperative Study Group

Mutations in Wilms tumor 1 (WT1) have been reported in 10-22 % of patients with cytogenetically normal acute myeloid leukemia (CN-AML), but the prognostic implications of these abnormalities have not been clarified in either adults or children. One hundred and fifty-seven pediatric AML patients were analyzed for WT1 mutations around hotspots at exons 7 and 9; however, amplification of the WT1 gene by the reverse transcriptase-polymerase chain reaction was not completed in four cases (2.5 %). Of the 153 evaluable patients, 10 patients (6.5 %) had a mutation in WT1. The incidence of WT1 mutations was significantly higher in CN-AML than in others (15.2 vs. 4.5 %, respectively, P = 0.03). Of the 10 WT1-mutated cases, eight (80 %) had mutations in other genes, including FLT3-ITD in two cases, FLT3-D835 mutation in two, KIT mutation in three, MLL-PTD in three, NRAS mutation in one, and KRAS mutation in two (in some cases, more than one additional gene was mutated). The incidences of KIT and FLT3-D835 mutations were significantly higher in patients with than in those without WT1 mutation. No significant differences were observed in the 3-year overall survival and disease-free survival; however, the presence of WT1 mutation was related to a poor prognosis in patients with CN-AML, excluding those with FLT3-ITD and those younger than 3 years.

High WT1 mRNA expression after induction chemotherapy and FLT3-ITD have prognostic impact in pediatric acute myeloid leukemia: a study of the Japanese Childhood AML Cooperative Study Group

The prognostic value of WT1 mRNA expression in pediatric acute myeloid leukemia (AML) remains controversial. A sample of newly diagnosed (n = 158) AML patients from the Japanese Childhood AML Cooperative Treatment Protocol, AML 99, were simultaneously analyzed for WT1 expression, cytogenetic abnormalities and gene alterations (FLT3, KIT, MLL, and RAS). WT1 expression (including more than 2,500 copies/μgRNA) was detected in 122 of the 158 (77.8 %) initial diagnostic AML bone marrow samples (median 45,500 copies/μgRNA). Higher WT1 expression was detected in French American British (FAB)-M0, M3, M7 and lower expression in M4 and M5. Higher WT1 expression was detected in AML with inv(16), t(15;17) and Down syndrome and lower in AML with 11q23 abnormalities. Multivariate analyses demonstrated that FLT3-internal tandem duplication (ITD), KIT mutation, MLL-partial tandem duplication were correlated with poor prognosis; however, higher WT1 expression was not. FLT3-ITD was correlated with WT1 expression and prognosis. Furthermore, 74 WT1 expression after induction chemotherapy was analyzed. Higher WT1 expression after induction chemotherapy was significantly correlated with M1 or M2/M3 marrow, FLT3-ITD and poor prognosis. Multivariate analyses in 74 AML patients revealed that FLT3-ITD, MLL-PTD, and KIT mutations were associated with poor prognosis; however, NRAS Mutation, KRAS mutation and high WT1 expression (>10,000 copies/μgRNA) did not show poor prognosis. Our findings suggest that higher WT1 expression at diagnosis does not correlate with poor prognosis, but that WT1 expression after induction chemotherapy is considered to be a useful predictor of clinical outcome in pediatric 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.

RAS mutations are frequent in FAB type M4 and M5 of acute myeloid leukemia, and related to late relapse: a study of the Japanese Childhood AML Cooperative Study Group

Mutations in RAS are frequent in acute myeloid leukemia (AML), and are thought to contribute to leukemogenesis in a subset of patients; however, their prognostic significance has not been firmly established. One hundred and fifty-seven pediatric patients with AML were analyzed for NRAS and KRAS mutations around hot spots at codons 12, 13, and 61. Twenty-nine patients (18.5%) had an activating mutation of RAS. We found KRAS mutations to be more frequent than NRAS mutations (18/29, 62.1% of patients with RAS mutation), in contrast to previous reports (18-40%). The frequency of RAS mutation was higher in French-American-British types M4 and M5 than other types (P = 0.02). There were no significant differences in other clinical manifestations or distribution in cytogenetic subgroups, or aberrations of other genes, including KIT mutation, FLT3-ITD, and MLL-PTD, between patients with and without RAS mutations. No significant differences were observed in the 3-year overall survival and disease-free survival; however, the presence of RAS mutation was related to late relapse. The occurrence of clinical events at relatively late period should be monitored for in AML patients with mutations in RAS.

The presence of central nervous system disease at diagnosis in pediatric acute myeloid leukemia does not affect survival: a Children's Oncology Group study

BACKGROUND

The presence of central nervous system (CNS) disease in pediatric acute myeloid leukemia (AML) is often thought to confer a worse prognosis. This study examined the outcome of children with AML who had CNS disease at diagnosis.

METHODS

Patients enrolled on Children's Cancer Group protocols 2861, 2891, 2941, and 2961 being treated for de novo AML were classified for the presence of CNS disease at diagnosis as CNS1 (<5 WBC in the CSF without blasts), CNS2 (<5 WBC in the CSF with blasts), or CNS3 (> or =5 WBC in the CSF with blasts). CNS disease at diagnosis was then analyzed regarding patient characteristics and outcome.

RESULTS

There was an incidence of CNS disease (i.e., CNS3 status) of 11% in the 1,459 patients analyzed in this study. The risk factors found are young age, high white cell count, hepatomegaly or splenomegaly at diagnosis, M4 subtype, chromosome 16 abnormalities, and hyperdiploid cytogenetics. There were no significant differences in overall survival, event free survival, or remission rates between the groups; however, a significant difference was seen between the CNS1 and CNS3 groups in disease free survival and isolated CNS relapse risk.

CONCLUSIONS

Patients with CNS disease at diagnosis have similar survival to those without CNS disease, although they have an increased incidence of isolated CNS relapse. Patients with CNS disease at diagnosis may warrant more aggressive CNS directed therapy.

Chemokine/chemokine receptor interactions in extramedullary leukaemia of the skin in childhood AML: differential roles for CCR2, CCR5, CXCR4 and CXCR7

Chemokine receptor/ligand interactions orchestrate the migration of cells to peripheral tissues such as the skin. We analysed chemokine receptor expression by acute myeloid leukaemic (AML) cells present in peripheral blood (n = 7), bone marrow (n = 6), or skin (n = 11) obtained from 15 paediatric AML patients with skin involvement and in 10 AML patients without skin involvement. High percentages of circulating CCR2(pos) AML cells were only detected in patients with extramedullary disease. Skin-residing AML cells displayed a different set of receptors in situ, namely: CCR5, CXCR4, CXCR7 and CX3CR1. These results suggest the involvement of different chemokine/chemokine receptor interactions in homing and retention of AML blasts in the skin.

Acute myeloid leukaemia diagnosed by intra-oral myeloid sarcoma. A case report

Myeloid sarcoma (MS) is a rare extramedullary malignant tumor composed of immature myeloid cells. It is strongly associated with a well known or covert acute myeloid leukaemia, chronic myeloproliferative diseases or myelodysplastic syndromes. Intraoral MS scarcely occurs. An unusual case of acute myeloid leukaemia, which was diagnosed by mandibular MS that was developed in the alveolar socket after a dental extraction, is reported. The histological examination (including immunohistochemical analysis) of a subsequent biopsy showed infiltration of the oral mucosa by neoplastic cells. This lesion was therefore classified as acute myeloid leukaemia. The patient was referred to oncologists that confirmed the initial diagnosis. The patient underwent chemotherapy and the mandibular tumor disappeared. Forty days later, a relapse of the disease, which appeared as a great-ulcerated lesion, was developed in the hard palate. Thirty days after the second chemotherapy had finished, a new intraoral tumor was developed in the vestibular maxillary gingiva. Review of the literature shows no report of intraoral relapse and particularly multiple relapse of a MS that involves the oral cavity. Even though MS is encountered infrequently in the oral cavity, it should be considered in the differential diagnosis of conditions (especially tumors) with a similar clinical appearance.

Stem cell transplant in the treatment of childhood biphenotypic acute leukemia

BACKGROUND

Many studies have found that biphenotypic acute leukemia (BAL) is associated with a poor outcome.

METHODS

We retrospectively reviewed the medical records and analyzed clinicopathological data on 25 children with BAL, and correlated outcomes with prognostic factors.

RESULTS

BAL constituted 4.4% of all acute childhood leukemia cases. In terms of immunophenotype, 14 patients had leukemia with myeloid plus B-lymphoid (M + B) marker, 7 with myeloid plus T-lymphoid (M + T) marker, and 4 with myeloid plus B-lymphoid and T-lymphoid (M + B + T) markers. Overall survival was superior in patients with the M + B immunophenotype (P = 0.004). Hematopoietic stem cell transplantation (HSCT) did not improve either overall survival or event-free survival compared to chemotherapy alone (hazard ratio 0.98, 95% CI 0.35-2.76, P = 0.966; hazard ratio 1.07, 95% CI 0.41-2.78, P = 0.88). Each of four patients with high-hyperdiploidy (>50 chromosomes) displayed a good treatment response and long-term overall survival even though these patients were treated with chemotherapy alone.

CONCLUSIONS

Treatment outcomes in childhood BAL patients differed by immunophenotype and cytogenetics. HSCT did not offer a significantly greater survival advantage compared to chemotherapy. While these data suggest that treatment should be individualized and stratified according to biologic characteristics and prognostic factors in BAL, prospective trial data are still needed.

Translocation (1;10)(p34;p15) in infant acute myeloid leukemia with extramedullary infiltration in multiple sites

Primary acute myeloid leukemia (AML) with extramedullary infiltration (EMI) in multiple sites is rare. Herein, we describe a case of infant AML with EMI in multiple sites. She had dyspnea and hypofibrinogenemia at diagnosis, and systemic computed tomography revealed EMI in the orbit, gingiva, bronchial pathway, and urinary tract. Bone marrow examination confirmed the diagnosis of AML with t(1;10)(p34;p15). No case of AML with t(1;10)(p34;p15) has been reported in the literature. At the present time, she remains free of disease 12 months after bone marrow transplantation (BMT) in the second complete remission.

Invasive aspergillosis of the small bowel in an infant with acute myeloid leukemia and intestinal obstruction

Acute myeloid leukemia was diagnosed in an infant with fever and pancytopenia. Intestinal obstruction was present at diagnosis and laparotomy performed after failure of conservative management demonstrated leukemic infiltration of the resected terminal ileum. Fever and intestinal obstruction persisted, necessitating a second ileal resection, which revealed invasive aspergillosis. Subsequent retrospective analysis identified occasional fungal hyphae in the initial resection specimen. With the combination of intensive chemotherapy and aggressive prolonged antifungal therapy the child survived. Invasive aspergillosis may unusually present at nonpulmonary sites at initial presentation of acute leukemia. Microbiological or histological diagnosis is needed to guide aggressive appropriate management.

The clinical feature of invasive fungal infection in pediatric patients with hematologic and malignant diseases: a 10-year analysis at a single institution at Japan

Invasive fungal infections (IFI) are an important complication in hematologic malignancies and stem-cell transplantation (SCT). However, there are limited data characterizing IFI in children. The clinical feature of IFI after chemotherapy and SCT were analyzed in 334 pediatric patients treated at Hokkaido University Hospital from 1997 to 2006. The cumulative incidence of IFI was 6.9%; this comprised cases of proven, probable and possible IFI at rates of 1.2%, 3.0%, and 2.7%, respectively. The infected lesions were lung in 14 patients, liver in 5 patients, brain in 3 patients, fungemia in 2 patients, kidney in 1 patient, and endophthalmitis in 1 patient. The mortality of IFI was 48.2%, excluding patients who died due to relapse and interstitial pneumonitis; in particular, 71.4% patients with a lung lesion (10/14) died due to IFI. Fifty-nine pediatric patients died in our institution over the 10-year period of the study and IFI was the direct cause of death in 18.6% (11/59) of the patients. Risk factors for IFI with chemotherapy and SCT were also analyzed. Univariate analysis showed that age at diagnosis older than 10 years, relapse of original disease, long-term administration of broad-spectrum antibiotics, and acute myelogenous leukemia (AML) were the risk factors for IFI. All patients with IFI received long-term antibiotic therapy. AML was most strongly associated using a multivariate analysis. The prognosis of IFI has been expected poor; therefore, prevention of this condition, especially for older patients with AML, would be important.

First demonstration of leukemia imaging with the proliferation marker 18F-fluorodeoxythymidine

Acute myeloid leukemia (AML) is a neoplasm of hematopoietic stem cells with partial or complete loss of the ability to differentiate but with preserved proliferation capacity. The aim of our study was to evaluate if the in vivo proliferation marker 3'-deoxy-3'-18F-fluorothymidine (FLT) is suitable for visualizing leukemia manifestation sites and if 18F-FLT is a surrogate marker for disease activity.

METHODS

In this pilot study, 10 patients with AML underwent pretherapeutic imaging with 18F-FLT PET or 18F-FLT PET/CT. The biodistribution of 18F-FLT was assessed 60 min after intravenous injection of the radiotracer. Standardized uptake values were calculated for reference segments of bone marrow, spleen, and normal organs. 18F-FLT PET in 10 patients with benign pulmonary nodules and the absence of malignant or inflammatory disease served as controls.

RESULTS

Retention of 18F-FLT was observed predominantly in bone marrow and spleen and was significantly higher in AML patients than in controls (mean 18F-FLT SUV in bone marrow, 11.5 and 6.6, P < 0.05; mean 18F-FLT SUV in spleen, 6.1 and 1.8, P < 0.05). Outside bone marrow, focal 18F-FLT uptake showed extramedullary manifestation sites of leukemia in 4 patients (meningeal disease, pericardial, abdominal, testicular, and lymph node), proven by other diagnostic procedures.

CONCLUSION

This pilot study indicated that PET using 18F-FLT is able to visualize extramedullary manifestation sites of AML and reflects disease activity. Because 18F-FLT uptake in bone marrow is caused by a combination of both neoplastic and normal hematopoietic cells, the correlation of 18F-FLT uptake in bone marrow and leukemic blast infiltration did not reach statistical significance.

Leukemia presenting as solid tumors: report of four pediatric cases and review of the literature

Leukemias are neoplasms that arise from the hematopoetic cells of bone marrow and usually spread first to peripheral blood. Involvement of extramedullary tissue during the course of a leukemia is common and usually does not represent a major diagnostic challenge when the history is available and specimen triage is optimal. In the context of a myeloid origin, extramedullary leukemias are referred to as granulocytic sarcomas, extramedullary myeloid tumors, extramedullary leukemias, or myeloid sarcomas. In the lymphoid category, leukemia involvement of tissue is conventionally distinguished from lymphoma by establishing the presence of 20% or more blasts in the bone marrow. A leukemia with an initial presentation outside the bone marrow mimicking a solid tumor is a rare but well-documented clinical encounter. Diagnostic difficulties may arise, especially when a specimen is not triaged properly due to the clinical presumption of a nonhematopoietic tumor. Systematic handling and proper triaging of biopsies are the keys to reducing diagnostic error and facilitating a timely diagnosis in this category. We report 4 case examples in the pediatric population, presenting in different anatomic sites. The value of fresh specimens and performing touch imprints is discussed and emphasized.

Presentation of acute promyelocytic leukemia as granulocytic sarcoma

Granulocytic sarcoma (GS) is a localized tumor composed of immature myeloid cells. This extramedullary tumor can present before, concurrent with or after the diagnosis of acute myeloid leukemia. GS is extremely uncommon in acute promyelocytic leukemia (APL). As a proportion of patients never develop systemic disease, correct and timely diagnosis may be rather difficult, but is a prerequisite for optimal outcome. GS should be considered in the differential diagnosis of children with unusual bone lesions. We describe a patient with GS who presented with symptoms mimicking osteomyelytis or rheumatoid disease.

Tandem duplications of MLL and FLT3 are correlated with poor prognoses in pediatric acute myeloid leukemia: a study of the Japanese childhood AML Cooperative Study Group

BACKGROUND

Mixed-lineage leukemia (MLL)-partial tandem duplication (PTD) is associated with poor prognosis in adult acute myeloid leukemia (AML), but its relationship to pediatric AML is unknown.

PROCEDURE

One hundred fifty-eight newly diagnosed AML patients, including 13 FAB-M3 and 10 Down syndrome (DS) patients, who were treated on the Japanese Childhood AML Cooperative Treatment Protocol AML 99 were analyzed for MLL-PTD, as well as internal tandem duplication (ITD) and the kinase domain mutation (D835Mt) in the FLT3 gene.

RESULTS

We found MLL-PTD in 21 (13.3%) of 158 AML patients, but not in FAB-M3 or DS patients. The differences between patients with and without MLL-PTD were significant for 3-year overall survival (OS) (56.3% vs. 83.2%, P = 0.018), disease-free survival (DFS) (41.7% vs. 69.6%, P = 0.010), and relapse rate (RR) (54.3% vs. 27.6%, P = 0.0085) of 135 AML patients excluding the FAB-M3 and DS patients. Furthermore, ITD and D835Mt in the FLT3 gene were found in 17 (12.6%) and 8 (5.9%) of these 135 patients, respectively. The differences between patients with FLT3-ITD and the wild-type allele were significant for 3-year OS (35.3% and 84.3%, P < 0.0000001), DFS (40.0% and 66.9%, P < 0.003), and RR (52.4% and 30.3%, P < 0.005). Coduplication of both genes was found in only 3 (1.9%) patients.

CONCLUSION

AML patients with FLT3-ITD, but not D835Mt, showed a poor prognosis. AML patients with MLL-PTD were also correlated with poor prognosis in this study.