Fusarium oxysporum disseminated infection in a teenage patient with a relapse of acute lymphoblastic leukemia - Case report and review of the literature.

Infections are still a significant cause of mortality in children with hematologic malignancies. Fusariosis is a relatively rare and opportunistic infection, which may present dangerous course and a poor prognosis. Below, we describe the fatal course of a 15-years old patient with a combined bone marrow and testicular relapse of ALL and multisystemic Fusariosis oxysporum infection with fulminant evolution. Despite aggressive therapy, which included multiagent antifungal treatment and surgical debridement, patient succumbed to the disease. The review of the literature was conducted and the need for early detection of fusarium symptoms was emphasized. The case encourages further research in the prevention and treatment of the illness.

Ophthalmologic Manifestations of Neuroblastoma: A Systemic Review.

Neuroblastoma (NBL) is the most common extracranial solid tumor found in pediatric patients. It develops from the sympathetic tract tissue. Although the symptoms are associated with tumor localization, sometimes NBL is manifested as ophthalmologic disorders. In this paper, we describe their incidence and the correlation with the prognosis. We searched 2 databases (PubMed and Web of Science) for papers published before April 2022, and concerned pediatric patients with NBL, which caused ophthalmologic changes. We collected 7 papers assessing the occurrence of ophthalmologic findings in the NBL patients, as well as 68 case reports presenting children with orbital changes and NBL, or with other tumors stemming from the sympathetic ganglia. The statistical analysis was performed to synthetize the data. The ophthalmologic signs occurred in 17.89% of the NBL cases; however, they were observed on presentation in 10.68%. The isolated ocular presentation was found in 2.56% of patients, whereas Horner syndrome was most frequent. The ophthalmologic symptoms correlated with patients' age, primary tumor site, and survival rate. NBL may be challenging to diagnose in cases with isolated ophthalmologic manifestations. Numerous possible ocular signs can be observed, which emphasize the need for multidisciplinary care with regard to the NBL patients.

Constitutional Mismatch Repair Deficiency Syndrome as a Cause of Numerous Malignancies in a Teenage Patient-A Case Report.

Constitutional mismatch repair deficiency syndrome is a genetic disorder resulting from a biallelic mutation in one of the following genes: MLH1, MSH2, MSH6, or PMS2. Individuals with constitutional mismatch repair deficiency are highly predisposed to develop both hematological and solid cancers in childhood, particularly lymphoma, brain tumors, and gastrointestinal neoplasms. We report a case of a boy diagnosed with B-cell acute lymphoblastic leukemia at the age of 3. In 2013, at the age of 6, head magnetic resonance imaging revealed hamartoma and astrocytoma lesions in the central nervous system. Two years after treatment completion, a diagnosis of precursor T-cell lymphoblastic lymphoma, accompanied by the vena cava syndrome, was established and treated accordingly. During treatment, a genetic test using Sanger sequencing was performed-a biallelic mutation in the MSH6 gene was detected. The study revealed that the mutation 17-bp c.2277-2293del. was inherited from the patient's mother. The second mutation, 5-bp c.1135_1139delAGAGA, developed inpatient de novo. At the age of 14, the diagnosis of isolated bone marrow relapse of acute lymphoblastic leukemia B-cell type was established. Due to the almost exceeded total dose of anthracyclines, the patient's treatment included blinatumomab, and subsequently, he was qualified for allogeneic hematopoietic cell transplantation. The patient remains in complete remission for 11 months after allogeneic hematopoietic stem cell transplantation under the care of the transplant center.

Successful Treatment of Large B-Cell Lymphoma in a Child with Compound Heterozygous Mutation in the ATM Gene.

Ataxia-telangiectasia (AT) is a multisystemic neurodegenerative inborn error of immunity (IEI) characterized by DNA repair defect, chromosomal instability, and hypersensitivity to ionizing radiation. Impaired DNA double-strand break repair determines a high risk of developing hematological malignancies, especially lymphoproliferative diseases. Poor response to treatment, excessive chemotherapy toxicities, and the need for avoiding exposure to ionizing radiation make the successful clinical management of patients with AT challenging for oncologists. We describe the favorable outcome of the LBCL with IRF4 rearrangement at stage III in a 7-year-old female patient diagnosed with AT. The patient was treated according to the B-HR arm of the INTER-B-NHL-COP 2010 protocol, including the administration of rituximab, cyclophosphamide, methotrexate, prednisone, etc. She presented excessive treatment toxicities despite individually reduced doses of methotrexate and cyclophosphamide. However, in the MRI there was no significant reduction in pathologic lymph nodes after three immunochemotherapy courses. Therefore, a lymph node biopsy was taken. Its subsequent histopathological examination revealed tuberculosis-like changes, though tuberculosis suspicion was excluded. After two following immunochemotherapy courses, PET-CT confirmed complete remission. From March 2022 onwards, the patient has remained in remission under the care of the outpatient children's oncology clinic.

Characteristics and treatment results of refractory and relapsed acute myeloid leukaemia in paediatric patients treated in Polish Paediatric Leukaemia/Lymphoma Study Group institutions according to the Protocol Acute Myeloid Leukaemia Berlin-Frankfurt-Munster 2012 and a review of novel treatment possibilities in paediatric acute myeloid leukaemia.

Introduction: This study aimed to present the clinical features and results of treatment of patients diagnosed with refractory or relapsed acute myeloid leukaemia (AML) in Polish Paediatric Leukaemia/Lymphoma Study Group (PPL/LSG) institutions, treated in accordance with the Protocol Acute Myeloid Leukaemia Berlin-Frankfurt-Munster 2012, as their first-line therapy. Material and methods: The outcome data of 10 patients with refractory AML (median age 9.5 years) and 30 with relapsed AML (median age 12 years) were analysed retrospectively. Re-induction was usually based on idarubicin, fludarabine, and cytarabine along with allogeneic haematopoietic stem cell transplant (allo-HSCT) in 5 patients with refractory AML and 7 relapsed AML children. Results: 37.5% (3/8) of refractory AML patients achieved second complete remission second complete remission (CRII). One of ten patients (1/10; 10%) was alive and stayed in complete remission for 34 months after the allo-HSCT. The probability of 3-year event-free survival (pEFS) in this group was 0.125 ±0.11. In the group of relapsed AML patients, the CRII was achieved in 9 patients (34%), and the probability of survival was: pEFS = 0.24 ±0.08; probability overall survival (pOS) = 0.34 ±0.09, with significantly better results achieved in patients who underwent allo-HSCT (pOS = 0.54 ±0.14 vs. 0.08 ±0.08, p < 0.0001). Conclusions: The prognosis of refractory AML and the first AML recurrence in children who were first-line treated in PPL/LSG centres according to Protocol Acute Myeloid Leukaemia Berlin-Frankfurt-Munster 2012 is poor. Failures of re-induction treatment particularly result from difficulties in achieving remission. Allogeneic HSCT improves prognosis in children with refractory and first recurrent AML, under the condition it is performed in complete remission. Novel therapeutic approaches are needed to increase the remission rate and improve the outcomes.

Prognostic significance of IKZF1 deletions and IKZF1plus profile in children with B-cell precursor acute lymphoblastic leukemia treated according to the ALL-IC BFM 2009 protocol.

The strongest predictors of outcome in pediatric B-cell precursor acute lymphoblastic leukemia (BCP-ALL) are minimal residual disease (MRD) and specific molecular abnormalities. One unfavorable prognostic factor is the presence of IKZF1 gene aberrations, particularly when co-occurring with high MRD level at the end of induction treatment. The present study determines the predictive value of a recently-defined IKZF1-plus (IKZF1plus ) microdeletion profile in 373 children with BCP-ALL treated according to the ALL-intercontinental Berlin-Frankfurt-Munster protocol 2009 protocol. IKZF1-wild type (IKZF1wt ) patients demonstrated lower leukemic burden parameters than those carrying IKZF1 deletion (IKZF1del [n = 26, 7.0%]) or IKZF1plus pattern (n = 34, 9.1%): (i) median blast percentage at diagnosis (78.0% vs. 86.9% vs. 86.0%; p = 0.021); (ii) median MRD level at day 15 of induction protocol (0.3% vs. 2.1% vs. 0.8%; p = 0.011); (iii) poor steroid response (7.6% vs. 26.5% vs. 12.5%; p = 0.010). Minimal residual disease level at day 33 (MRD33) exceeding 10-4 was more frequently observed in both the IKZF1del and IKZF1plus subgroups than in IKZF1wt patients (n = 9 [36.0%] vs. n = 13 [41.9%] vs. n = 70 [24.0%], p = 0.051). IKZF1plus individuals showed a tendency for a lower MRD reduction between day 15 and 33 compared to IKZF1del patients (p = 0.124). IKZF1del and IKZF1plus patients showed decreased relapse-free survival (HR [95%CI] for IKZF1wt as reference = 2.72 [1.21-6.11] and 2.00 [0.87-4.49], respectively, p = 0.023). Both genetic markers including IKZF1del and IKZF1plus microdeletion profile provide additional predictive value of treatment outcome in childhood BCP-ALL and may contribute to more efficient patient stratification; the same is true in MRD guided protocols, which are based on flow cytometric measurements on day 15 of induction protocol.

Expression of CD73 on leukemic blasts increases during follow-up - a promising candidate marker for minimal residual disease detection in pediatric B-cell precursor acute lymphoblastic leukemia.

Flow cytometry (FCM) is a precise and well-established tool to assess the minimal residual disease (MRD) level in childhood acute lymphoblastic leukemia (ALL). It is crucial to distinguish leukemic cells from their normal counterparts; thus new markers should be evaluated, to increase the accuracy of the analysis. The expression of CD73 on blast cells was measured and compared at the day of diagnosis and at days 15 and 33 of treatment. To determine antigen expression levels, a normalized scale based on median fluorescence intensity (nMFI) was used. The study group consisted of 188 patients from the Polish Pediatric Leukemia and Lymphoma Study Group. From 177 patients with positive MRD at day 15 of treatment, in 147 (83.1%) cases an increase of CD73 expression was observed (mean increase of +17 nMFI units). In addition, an increase of CD73 expression was noted in 26 of 31 (83.9%) patients at day 33 of treatment. In turn, a decrease of CD73 expression was observed only in 13/177 (7.3%) and 1/31 (3.2%) cases at days 15 and 33 of treatment, respectively. In 17 (9.6%) patients no change in expression of CD73 between diagnosis and day 15 of treatment was observed. In the great majority of cases the expression of CD73 is not only stable but increases during the early stages of treatment, which makes it a very useful marker to be used for MRD monitoring in childhood B-cell precursor (BCP)-ALL patients.

Incidence of Horner syndrome associated with neuroblastic disease.

PURPOSE: Horner syndrome (HS) manifests in unilateral ptosis, miosis, enophthalmos, and anhedonia. It is most commonly caused by trauma or surgical procedures, but can also occur in pediatric patients as a result of tumors, especially neuroblastoma (NBL). The objective of this study was to analyze the incidence of HS in patients diagnosed with NBL. METHODS: A retrospective analysis of data collected at the Department of Pediatric Oncology, Hematology, and Transplantology from 2004 to 2019 was performed. The study group included 119 patients younger than 18 years old, with 62 girls and 57 boys. All of them were diagnosed with a neuroblastic tumor. RESULTS: Among the 119 patients, eight children (6.72%) were diagnosed with HS associated with NBL. Three of these patients presented to the clinic with HS, whereas HS developed after the surgical procedure to remove the tumor in four patients. The adrenal gland was the most frequent localization of the tumor. However, HS occurred more frequently in patients with mediastinum tumors. As a presenting symptom, HS occurred in 2 of 11 cases (18.18%) with mediastinum localization. All of the patients with HS were younger than 2 years old. CONCLUSION: Investigation of the cause of isolated HS is crucial because it can be the first symptom of NBL. However, the surgical procedure itself increases the risk of HS as a complication of NBL treatment.

Multicolor flow cytometry immunophenotyping and characterization of aneuploidy in pediatric B-cell precursor acute lymphoblastic leukemia.

The aim of this study was to assess the incidence of DNA aneuploidy in Polish children with B-cell precursor acute lymphoblastic leukemia (BCP-ALL) and the relationship between aneuploidy and immunological phenotype, age, leukocyte count, S-phase fraction (SPF) and early response to induction chemotherapy assessed by the percentage of residual blast cells in bone marrow aspirates. The study group consisted of 267 patients. DNA content and immunophenotype were assessed in the bone marrow before treatment using multicolor flow cytometry (FC). DNA aneuploidy was detected in 50/267 (19%) patients. High hyperdiploidy was found to be associated with lower leukocyte count (p = 0.006) and common ALL immunophenotype. Flow cytometry analysis revealed that high hyperdiploid BCP-ALL patients showed significantly higher expression of CD9, CD20, CD22, CD58, CD66c, CD86 and CD123 antigens as compared to other groups of ploidy. In contrast, CD45 showed decreased expression. The percentage of leukemic blasts at diagnosis was lower in high hyperdiploid BCP-ALL cases than in diploid (79% vs. 85.7%, p = 0.001). The difference in minimal residual disease (MRD) levels on day 15 and 33 of induction therapy between analyzed groups was not significant. This study showed that high hyperdiploidy is associated with lower WBC count and specific immunological phenotype. Flow cytometric evaluation of expression of selected antigens can be used for fast identification of markers of aneuploidy in pediatric BCP-ALL, before genetic tests results are available. Understanding the biological significance of aneuploidy in leukemia can potentially be exploited therapeutically using targeted therapies against specific blast cell subclones.

Long-term brain status and cognitive impairment in children treated for high-risk acute lymphoblastic leukemia with and without allogeneic hematopoietic stem cell transplantation: A single-center study.

AIM: The aim of the study was to assess long-term consequences of central nervous system (CNS) prophylaxis in patients with high-risk ALL (HR-ALL) treated according to ALL IC-BFM 2002 and to compare observed abnormalities in patients who underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT) with those who received only prophylactic CNS irradiation (12 Gy) and with control group. PATIENTS AND METHODS: We studied 29 patients with HR-ALL in CR1 after treatment according to protocol ALL IC-BFM 2002 (14 with allo-HSCT conditioned with fractionated total body irradiation [FTBI] and 15 without HSCT) and 16 children with newly diagnosed ALL (control group). The median time from therapy completion to evaluation was 5 years. To assess brain status, volumetric T1-weighted sequences of magnetic resonance imaging were used. Neuropsychological assessment based on battery neuropsychological tests. RESULTS: Transplanted patients had significantly lower volumes of white and gray matter (P = .048 and P < .001) and also of subcortical structures, including the thalamus (P < .001), the hippocampus (P = .007), the putamen (P = .011), the globus pallidus (P = .001), and the accumbens (P < .001). In addition, these patients had generally lower cognitive performance, especially in vocabulary (P = .011), visuospatial ability (P = .047), executive functions and attention (P = .034; P = .002; P = .048), and processing speed (P = .049 and P = .037). The thalamus volume is correlated with neuropsychological performance in verbal functions (P < .001), executive functions (P < .001 and P = .024), and processing speed (P < .001). CONCLUSIONS: In pediatric patients treated for ALL, FTBI-based preparative regimen preceding allo-HSCT causes reduction of subcortical structure volumes and decline in cognitive performance. The observed long-term structural and functional CNS sequelae are significantly more pronounced in transplanted HR-ALL patients than in those treated with prophylactic CNS- radiotherapy only.

First case of convalescent plasma transfusion in a child with COVID-19-associated severe aplastic anemia.

We present the case of a six-year-old girl with severe COVID-19, in whom SARS-CoV-2 was successfully eliminated after convalescent plasma transfusion. Children show a variable clinical course of COVID-19, from asymptomatic to critical. In our patient, we diagnosed COVID-19-associated aplastic anemia with severe pancytopenia. The correlation between SARS-CoV-2 infection with aplastic anemia remains unclear. At the beginning of the disease, we used antiviral drugs and immune modulators as therapy but without any positive results. After providing a transfusion of convalescent plasma, the elimination of SARS-CoV-2 was observed. We did not observe any adverse events of this treatment. The girl still has a diagnosis of aplastic anemia and requires specialist therapy.

GATA3 germline variant is associated with CRLF2 expression and predicts outcome in pediatric B-cell precursor acute lymphoblastic leukemia.

The germline variant at rs3824662 in GATA3 is a risk locus for Philadelphia-like acute lymphoblastic leukemia (Ph-like ALL), the biological subtype of B-cell precursor (BCP)-ALL defined by a distinct gene expression profile and the presence of specific somatic aberrations including rearrangements of CRLF2. In this study, we investigated whether rs3824662 in GATA3 associates with CRLF2 expression in leukemic cells and predicts prognosis in pediatric BCP-ALL patients treated according to the ALL Intercontinental Berlin-Frankfurt-Münster (IC BFM) 2009 (n = 645) and the ALL IC BFM 2002 (n = 216) protocols. High expression of CRLF2 was observed at both protein and mRNA levels (fourfold higher in AA than in CA + CC) among GATA3 AA variant carriers, independent of the presence of P2RY8-CRLF2 fusion. Additionally, the AA variant at rs3824662 was a significant factor affecting minimal residual disease level at the end of induction phase and overall survival regardless of the risk group and the protocol. The germline variant at rs3824662 in GATA3 is a prognostic factor which associates with CRLF2 expression in leukemic cells supporting the hypothesis that GATA3 may have a regulatory effect on the CRLF2 pathway in pediatric BCP-ALL.

Successful Management of a Child With Drug-induced Necrotizing Pancreatitis During Acute Lymphoblastic Leukemia Therapy: A Case Report.

Acute pancreatitis in children acute lymphoblastic leukemia is commonly caused by drugs, for example, L-Asparaginase, pegapargase, steroids. The incidence of this complication is estimated at 6.7% to 18%. Although the majority of drug-induced acute pancreatitis cases are mild, severe cases can rarely occur. This work presents a case of successful management of a child with drug-induced necrotizing pancreatitis during acute lymphoblastic leukemia therapy. This case illustrates that comprehensive care and immediate intensive treatment can rescue patient despite poor prognosis. Administration of octreotide may serve a role in limiting the severity of the disease.

Clinical characteristics and analysis of treatment result in children with Ph-positive acute lymphoblastic leukaemia in Poland between 2005 and 2017.

OBJECTIVE: The aim of this study was to analyse the clinical characteristics and outcome of children diagnosed with Ph+ ALL. MATERIAL AND METHODS: A total of 2591 newly diagnosed ALL children were treated in Poland between the years 2005 and 2017. Of those, 44 were diagnosed with Ph(+) ALL. The patients were treated according to protocols: ALL IC-BFM 2002 and 2009 (26 patients), EsPhALL (12 patients), initially ALL IC-BFM and then EsPhALL (6 patients). RESULTS: The median of follow-up in the observed group was 3 years. Overall survival (OS) and event-free survival (EFS) of Ph+ ALL group were 0.73 and 0.64. OS and EFS of patients after HSCT were 0.78 and 0.66, while without HSCT were 0.6 and 0.6, P = 0.27 and 0.63. OS was 0.8 for patients treated with chemotherapy plus imatinib and 0.61 for chemotherapy alone, P = 0.22, while EFS was 0.66 (imatinib therapy) and 0. 61 (without imatinib), P = 0.41. CONCLUSION: Our study suggests that adding imatinib to intensive chemotherapy seems to improve outcome. However, this study was limited by a small number of patients and a variety of chemotherapy regimens with or without imatinib.

Translocation t(8;14)(q24;q11) with concurrent PTEN alterations and deletions of STIL/TAL1 and CDKN2A/B in a pediatric case of acute T-lymphoblastic leukemia: A genetic profile associated with adverse prognosis.

We report a pediatric case of acute T-lymphoblastic leukemia (T-ALL) with NOTCH1wt , FBXW7wt , STIL/TAL1, and PTEN (exons 2, 3, 4, 5) monoallelic deletions, biallelic CDKN2A/B deletion, and a minor t(8;14)(q24;q11)-positive subclone. Undetectable by a flow cytometric minimal residual disease assay, the t(8;14)(q24;q11) subclone expanded as detected by fluorescence in situ hybridization from 5% at diagnosis to 26% before consolidation and 100% at relapse bearing a monoallelic deletion (exons 2, 3) with a new frameshift mutation of PTEN and the same set of remaining molecular alterations. This case documents an unfavorable prognostic potential of a co-occurrence of this set of molecular genetic events and addresses risk stratification in T-ALL.

Long-term brain structural magnetic resonance imaging and cognitive functioning in children treated for acute lymphoblastic leukemia with high-dose methotrexate chemotherapy alone or combined with CNS radiotherapy at reduced total dose to 12 Gy.

INTRODUCTION: The aim of this study was to assess the long-term side effects of central nervous system prophylaxis (high-dose chemotherapy alone vs chemotherapy and CNS radiotherapy) according to the ALL IC-BFM 2002. METHODS: Thirty-tree children aged 6.7-19.9 years have been studied. The control group consisted of 12 children newly diagnosed with acute lymphoblastic leukemia. We assessed subcortical gray matter volume using automatic MRI segmentation and cognitive performance to identify differences between two therapeutic schemes and patients prior to treatment. RESULTS: Patients treated with chemotherapy and CNS radiotherapy had smaller hippocampi than two other subgroups and lower IQ score than patients treated with chemotherapy alone. Both treated groups, whether with chemotherapy only or in combination with CNS radiotherapy, had significantly lower volumes of caudate nucleus and performed significantly worse on measures of verbal fluency in comparison with patients prior to treatment. There were no differences in the mean volumes of total white matter, total gray matter, thalamus, putamen, and amygdala between the studied groups. CONCLUSION: In all children treated according to the ALL IC-BFM 2002 with high-dose chemotherapy, both decreased volume of selected subcortical structures and cognitive impairment was observed, especially in children who received chemotherapy in combination with reduced dose CNS radiotherapy. In all children treated according to the ALL IC-BFM 2002 with high-dose chemotherapy, both decreased volume of selected subcortical structures and cognitive impairment were observed, especially in children who received chemotherapy in combination with CNS radiotherapy.

Atypical thymic carcinoid manifesting with nephrotic-range proteinuria in a 7-year-old boy.

BACKGROUND: Nephrotic-range proteinuria as a paraneoplastic syndrome (PNS) is an exceptional presentation, especially in children. It is usually associated with hematologic malignancies. Solid tumors are very rare causes of proteinuria. CASE-DIAGNOSIS/TREATMENT: We present the case of a 7-year-old boy with an extremely rare atypical thymic carcinoid accompanied by nephrotic-range proteinuria as PNS. The kidney biopsy was consistent with minimal change disease (MCD). Tests for a neuroendocrine tumor were performed due to symptoms of hypercortisolemia and an elevated concentration of chromogranin A in the serum. The chest computed tomography revealed a tumor in the anterior mediastinum, which was diagnosed as an atypical thymic carcinoid. A complete resolution of the nephrotic-range proteinuria was observed within 1 week after the first thoracoscopic surgery, with almost complete reduction of the tumor mass. CONCLUSIONS: This extremely rare case shows that MCD can occur as a PNS even in children. Nephrotic-range proteinuria can be a symptom of malignant solid tumor. This case highlights the possibility of secondary causes of MCD in children.

Outcome of acute lymphoblastic leukemia in children with down syndrome-Polish pediatric leukemia and lymphoma study group report.

Children with Down syndrome (DS) have a 20-fold increased risk of developing leukemia compared with the general population. The aim of the study was to analyze the outcome of patients diagnosed with Down syndrome and acute lymphoblastic leukemia (ALL) in Poland between the years 2003 and 2010. A total of 1848 children were diagnosed with ALL (810 females and 1038 males). Of those, 41 (2.2%) had DS. The children were classified into three risk groups: a standard-risk group-14 patients, an intermediate-risk group-24, a high-risk group-3. All patients were treated according to ALLIC 2002 protocol. The median observation time of all patients was 6.1 years, and in patients with DS 5.3 years. Five-year overall survival (OS) was the same in all patients (86% vs 86%, long-rank test, p = .9). The relapse-free survival (RFS) was calculated as 73% in patients with DS and 81% in patients without DS during a median observation time (long-rank test, p = .3). No statistically significant differences were found in the incidence of nonrelapse mortality between those two groups of patients (p = .72). The study was based on children with ALL and Down syndrome who were treated with an identical therapy schedule as ALL patients without DS, according to risk group. This fact can increase the value of the presented results.

Massively parallel targeted resequencing reveals novel genetic variants associated with aspergillosis in paediatric patients with haematological malignancies.

This study aimed to find novel genetic variants of susceptibility to aspaergillosis in paediatric patients with haematological malignancies. Complete sequences of fifteen genes of human innate immunity (CCL2, CCR2, CD209, CLEC6A, CLEC7A and ten TLR genes) were studied in 40 patients diagnosed with haematological disorders (20 unaffected and 20 affected by aspergillosis). All samples were sequenced with MiSeq (Illumina) and 454 (Roche Diagnostics) technologies. Statistical significance of the differences between studied groups was determined using the two-tailed Fisher's exact test. Sixty variants of potential importance were identified, the vast majority of which are located in non-coding parts of the targeted genes. At the threshold of p < 0.000005, one intergenic (TLR2 rs4585282) and one intronic variant (CLEC6A rs12099687) were found significant between the case and control groups for genotype and allele frequencies, respectively. Rs12099687 in CLEC6A was predicted to constitute an alternative isoform or cryptic splice site, which potentially changes activity of the Dectin-2 protein. Overall, we assume that the two strongest associations reported in this study are expected to be reproducible even in the absence of other evidence, while another twelve associations may be strong enough to justify additional research in larger cohorts.

Myeloid sarcoma in children - diagnostic and therapeutic difficulties.

Myeloid sarcoma (MS) is a malignant extramedullary tumour, which consists of immature cells of myeloid origin. It may occur de novo, concurrently or precede the diagnosis of acute myeloid leukemia (AML), myelodysplastic syndrome (MDS) or chronic myeloid leukemia (CML). MS can also be a manifestation of the relapse of the disease. The more frequent sites of involvement are the skin, orbit, bone, periosteum, lymph nodes, gastrointestinal tract, soft tissue, central nervous system and testis. Because of its different localization and symptoms, and the lack of diagnostics algorithm, myeloid sarcoma is a real diagnostic challenge, in particular in patients without initial bone marrow involvement. The correct diagnosis of MS is important for adequate therapy, which is often delayed because of a high misdiagnosis rate. In the paper, the role of immunohistochemistry, cytogenetic and molecular genetic analyses is emphasized as well as the breadth of unclear aspects of this disorder in children.