[Myelofibrosis regressing under corticotherapy and intravenous immunoglobulins in an infant]

Pediatric autoimmune myelofibrosis: Experience from a large pediatric tertiary care center

Autoimmune myelofibrosis (AIMF) is a rare disorder characterized by cytopenias and autoimmunity, with characteristic bone marrow findings that include lymphocytic infiltration and fibrosis. AIMF is described predominantly in adult populations who have systemic lupus erythematosis (SLE), with scant pediatric cases described mainly in older adolescents with SLE. Here, we described the largest single-center pediatric experience of pediatric autoimmune myelofibrosis (PAIMF) series, demonstrating both similarities and distinctions from the adult experience. Patients overall respond well to steroid therapy, but these patients were significantly younger, infrequently carried a diagnosis of SLE, and causative genetic lesions were identified in many cases.

A Rare Case of Primary Myelofibrosis in a 14-Year-Old Patient With Congenital Asplenia

Primary myelofibrosis (PMF) is rarely diagnosed in children, and in most cases in children younger than 3 years old. Pediatric PMF generally follows a benign course and is usually managed supportively with blood transfusions and prophylactic antibiotics for infections. We present a case of a 17-year-old girl diagnosed with PMF at the age of 14 years. A computed tomography scan performed at the time of an appendectomy showed congenital asplenism. To our knowledge, this is only the third case of myelofibrosis and congenital asplenism to be reported in the literature. Whether asplenism contributed to the development of myelofibrosis is not known.

Myeloproliferative Neoplasms in Children

Myeloproliferative neoplasms (MPN) are a group of clonal hematopoietic stem cell disorders characterized by aberrant proliferation of one or more myeloid lineages often with increased immature cells in the peripheral blood. The three classical BCR-ABL-negative MPNs are: 1) polycythemia vera (PV), 2) essential thrombocythemia (ET), and 3) primary myelofibrosis (PMF), which are typically disorders of older adults and are exceedingly rare in children. The diagnostic criteria for MPNs remain largely defined by clinical, laboratory and histopathology assessments in adults, but they have been applied to the pediatric population. The discovery of the JAK2 V617F mutation, and more recently, MPL and CALR mutations, are major landmarks in the understanding of MPNs. Nevertheless, they rarely occur in children, posing a significant diagnostic challenge given the lack of an objective, clonal marker. Therefore, in pediatric patients, the diagnosis must rely heavily on clinical and laboratory factors, and exclusion of secondary disorders to make an accurate diagnosis of MPN. This review focuses on the clinical presentation, diagnostic work up, differential diagnosis, treatment and prognosis of the classical BCR-ABL-negative MPNs (PV, ET and PMF) in children and highlights key differences to the adult diseases. Particular attention will be given to pediatric PMF, as it is the only disorder of this group that is observed in infants and young children, and in many ways appears to be a unique entity compared to adult PMF.

[Megakaryoblastic acute leukemia: bone and joint manifestations in a 7-month-old child]

Acute megakaryoblastic leukemia accounts for approximately 3-10% of acute myeloid leukemia in children. Its diagnosis may be difficult because of associated myelofibrosis. We report the case of a 7-month-old child who presented hepatomegaly with bicytopenia. She also developed bone and joint pain with recurrent aseptic arthritis. We suggested the diagnosis of megakaryoblastic leukemia early but multiple bone marrow investigations had been processed without positive results because of sampling problems and lack of abnormal cells in the morphological, phenotypic, and cytogenetic examinations. We had a variety of indirect evidence for our assumption: the x-ray showing periosteal new bone, lytic lesions and metaphyseal bands, bone marrow aspirate smears with micromegakaryocytes, and bone marrow biopsy suggesting myelofibrosis. This was very suggestive of leukemia but we could not prove it and we finally found megakaryoblasts on bone marrow aspirate smears after more than 2 months of investigation and initiated a course of corticosteroids.

Transient myelofibrosis with autoimmune pancytopenia: a case report

INTRODUCTION

Myelofibrosis associated with myelodysplasia is thought to herald poor prognosis in myelodysplastic syndrome (MDS).

CASE REPORT

A 7-month-old boy presented with fever (39 degrees C), pancytopenia, and slight hepatosplenomegaly (3 and 2 cm, respectively). Bone marrow showed hypercellularity, hyperplasia of erythroblasts, and also myelofibrosis. IgG was 1,136 mg/dL, IgA was 131 mg/dL, and IgM was 89 mg/dL. Antinuclear and antineutrophil antibodies, red-blood-cell-associated IgG, antiplatelet antibodies, and Coombs test were positive. Karyotype was 46XY. No viral cause was evidenced. Mild myelodysplasia was revealed two months later, but was insufficient to support a diagnosis of MDS. The boy was treated with transfusion of packed cells, prednisolone 2 mg/kg/day for 3 weeks associated with intravenous gammaglobulin 400 mg/kg/day for 5 days. Direct Coombs remained positive 1 month after treatment for 5 months, myelofibrosis persisted for 3 months, and neutropenia for 21 months. After 3-year follow-up, hematological data were normal without any therapeutic intervention.

CONCLUSION

Myelofibrosis associated with mild myelodysplasia and pancytopenia can have a benign evolution in infants and young children.