Juvenile xanthogranuloma in a child with previously unsuspected neurofibromatosis type 1 and juvenile myelomonocytic leukemia

The association of neurofibromatosis 1 (NF1), juvenile xanthogranulomas (JXG), and juvenile myelomonocytic leukemia (JMML) has been previously reported. We describe herein this triad in a Caucasian male infant with a pathogenic mutation in the NF1 gene (neurofibromin). The clinical course from initial presentation to final diagnosis is detailed; the physical features and hematologic characteristics are discussed. The patient underwent bone marrow transplantation and is currently in remission. Children with concurrent cutaneous café‐au‐lait and JXG lesions should be evaluated and monitored closely for the possible development of JMML. Pediatr Blood Cancer 2010; 54:173–175. © 2009 Wiley‐Liss, Inc.     

The evolution of juvenile myelomonocytic leukemia in a female patient with paternally inherited neurofibromatosis type 1

The most common myeloid malignancy seen in children with neurofibromatosis type 1 (NF-1) is juvenile myelomonocytic leukemia (JMML), a myeloproliferative disease. The vast majority of these children have inherited the neurocutaneous disease from an affected mother; boys are more often affected than girls. We present the rare finding of a 7-year-old girl with NF-1 who developed JMML. She inherited her NF-1 from the father. At the time of her initial presentation, clonogenic assays of bone marrow mononuclear cells did not show the spontaneous growth of granulocyte-macrophage colony-forming units or hypersensitivity to granulocyte-macrophage colony-stimulating factor that is characteristic of this disorder. After 1 month, repeat evaluations of the patient's clinical and laboratory test results became fully consistent with those for a diagnosis of JMML. This illustrates the stepwise evolution of this myeloproliferative disorder in NF-1 and the importance of close follow-up and reassessment of these patients. Our case is only the second report of JMML in a girl who inherited NF-1 from her father.     

Biotinidase deficiency and juvenile myelomonocytic leukemia in a Turkish infant of consanguineous parents

Here, a case is presented with two rare genetic disorders, biotinidase deficiency and juvenile myelomonocytic leukemia, in a Turkish infant. This case may serve as a reminder that the diagnosis of a genetic disorder does not exclude the possibility of a second congenital but acquired disease.     

Development of T-cell acute lymphoblastic leukemia in a patient in very long lasting complete remission of juvenile myelomonocytic leukemia

Juvenile myelomonocytic leukemia (JMML) occurs with an incidence of 1.2 per million children a year, and represents 18% to 30% of all myelodysplastic (MDS) and myeloproliferative (MPS) disorders in the age group below 15, being by far the most common MDS/MPS in children younger than 4 years. The only therapeutic approach which results in a definitive cure of patients with JMML is myeloablative chemo-therapy/radio-therapy, followed by allogeneic hematopoietic cell transplantation. Few cases of transformation of JMML in acute lymphoblastic leukemia have been reported. We describe a child with JMML diagnosed at the age of 4 months in whom complete remission was achieved with 13-cis retinoic acid and cytosine-arabinoside and was sustained for 7 years with no maintenance therapy. Ninety-eight months after the diagnosis of JMML was established, overt T-cell leukemia developed. Treatment with acute lymphoblastic leukemia (ALL)-directed chemotherapy induced complete restoration of normal hemopoiesis, but testicular involvement persisted. The patient died after transplantation with unrelated cord blood. This case suggests that JMML is a true stem cell disorder and that stem cell transplantation should be considered, even in patients with a very favorable clinical course.     

The strange case of the lost NRAS mutation in a child with juvenile myelomonocytic leukemia

Juvenile myelomonocytic leukemia (JMML) is a rare myelodysplastic/myeloproliferative disorder of early childhood characterized by mutations of the RAS-RAF-MAP kinase signaling pathway. We report the case of a child with a diagnosis of JMML carrying two mutations of NRAS gene (c.37G>C and c.38G>A) independently occurring in long-term culture initiating cells. However, only the former was consistently found in more mature hematopoietic cells, suggesting that cancer transformation may lead to the loss of a mutation. This case also indicates that molecular analysis on cell types other than peripheral blood leukocytes may be useful to obtain relevant biological information on JMML pathogenesis.     

Development of acute megakaryoblastic leukemia from a minor clone in a Down syndrome patient with clinically overt transient myeloproliferative disorder

A Down syndrome male showed leukocytosis from birth and was diagnosed as transient myeloproliferative disorder (TMD). Eight months later, his condition had progressed to myelodysplastic syndrome after spontaneous resolution, and it then evolved to acute megakaryoblastic leukemia (AMKL) at the age of 20 months. Sequencing analysis showed that the predominant TMD and AMKL clones had different GATA1 mutations, although a minor TMD clone identical to the AMKL clone was present at birth. These observations suggest that a minor clone rather than the predominant clone at the time of TMD may give rise to AMKL later on.     

Transient myeloproliferative disorder in neonates with and without Down syndrome: a tale of 2 syndromes

Transient myeloproliferative disorder (TMD) in newborns with Down syndrome (DS) has been well described. We report 4 newborns, 2 with DS and 2 without DS, who developed TMD. One newborn with DS developed multiorgan failure and died despite treatment with low-dose cytarabine. In 3 newborns, the TMD resolved spontaneously. Two of these patients, 1 with and 1 without DS developed leukemia on subsequent follow-up and were treated successfully. We reviewed the clinical and laboratory data on 14 non-DS infants with TMD reported in the literature. According to limited data, these patients are more likely to develop leukemia than DS patients, however their outcome is better.     

Skin lesions in a boy with X-linked lymphoproliferative disorder: comparison of 5 SH2D1A deletion cases

SH2D1A gene defects are the cause of X-linked lymphoproliferative disorder (XLP-1), a rare condition characterized by severe immune dysregulation. We present a patient lacking the typical symptoms of XLP-1, but experiencing a severe unusual skin condition encompassing features of dermatosclerosis and vesiculobullous skin disease. A maternal cousin of the patient was diagnosed with XLP-1 and found to carry a deletion of the SH2D1A gene. SH2D1A deletion was also identified in our patient, which offered a possible explanation for his skin symptoms. Subsequent analysis showed that the deletion in both cousins was identical and involved the whole SH2D1A gene and a part of the adjacent ODZ1 gene. High phenotypic variability of XLP-1 observed in this family prompted us to analyze the genotype-phenotype correlation of 2 different-sized deletions involving SH2D1A and ODZ1 in 5 patients from 2 families, and we report the clinical and laboratory data on these individuals. Our findings illustrate the wide clinical variability of XLP-1, both inter- and intrafamilial, which may complicate the diagnosis of this condition. The comparison of phenotypes of our patients argues against a strong involvement of the ODZ1 gene in the skin disorder and other symptoms observed in our index patient. His hitherto not described severe skin condition extends the phenotypic range of XLP-1.     

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 NOTCH1^wt, FBXW7^wt, 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.