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HomePediatrics: General MedicinePediatric Myelodysplasia

Pediatric Myelodysplasia

Practice Essentials

Myelodysplasia encompasses a heterogenous group of disorders that result in ineffective hematopoiesis. Historically, a wide variety of terms have been used to describe these syndromes, including preleukemia, refractory anemia with excess of myeloblasts, subacute myeloid leukemia, oligoleukemia,
odoleukemia, and dysmyelopoietic syndromes.

The myelodysplasia syndromes (MDSs) are clonal stem cell disorders characterized by progressive cytopenia or cytopenias, usually in the presence of a hypercellular bone marrow and multilineage dysplasia. Usually, all 3 cell lines (myeloid/monocyte, erythroid, megakaryocyte) are involved. Myelodysplasia syndrome is rare in childhood, and most children have a rapidly progressive course. Myelodysplasia disorders have been defined by their predilection to evolve into acute myeloid leukemias (AML), yet not all cases terminate in leukemia.

The 2001 World Health Organization (WHO) classification system incorporated cytogenetics into the the French-American-British (FAB) cooperative group morphologic classification system for adult myelodysplasia syndrome.
The FAB system, based on peripheral blood and bone marrow morphology, defined 5 morphologic categories that represent a transition between myelodysplasia syndrome and AML.

Although many of the features observed in childhood myelodysplasia syndrome are similar to those in the adult form of the disease, unique differences are also noted, especially when children lack blasts in the peripheral blood or bone marrow. The 2008 World Health Organization (WHO) classification system has now formally recognized the unique nature of childhood myelodysplasia syndrome with the inclusion of a provisional entity, refractory cytopenia of childhood (RCC) (ICD-O code 9985/3).
Down syndrome–associated myelodysplasia syndrome is also categorized separately by the WHO as “myeloid proliferations related to Down syndrome.”

Signs and symptoms of pediatric myelodysplasia

Patients with myelodysplasia may present with symptoms of hematopoietic failure, including infection, bleeding, bruising, fatigue, weight loss, and dyspnea upon exertion. However, no clinical symptoms are reported in up to 20% of children with RCC, in whom cytopenia(s) or isolated splenomegaly is discovered during routine evaluation for an unrelated symptom.

Splenomegaly and hepatomegaly are more common in childhood myelodysplasia syndrome and predominate in juvenile myelomonocytic leukemia (JMML).

Workup in pediatric myelodysplasia

Bone marrow aspiration and biopsy are essential to establish the diagnosis and to classify the myelodysplasia syndrome.

Laboratory studies include the following:

Complete blood count (CBC)

Quantitative hemoglobin electrophoresis

Cytogenetic studies

Fanconi anemia test

Paroxysmal nocturnal hemoglobinuria (PNH) test

Human leukocyte antigen (HLA) typing

Management of pediatric myelodysplasia

Once the diagnosis is established, management involves supportive care that includes transfusion, treatment of infections, and a search for an allogeneic stem cell donor. Myelodysplasia syndrome is an incurable disease without hematopoietic stem cell transplantation (HSCT).
Allogeneic HSCT regimens are associated with a 30-50% event-free survival rate at 3 years. Stem cell transplant timing is determined on a case-by-case basis because the temporal course of the disease is highly variable. The optimal conditioning regimen has not been determined.

As cytopenia(s) progress, most children need central venous access for transfusions. This usually requires surgical placement of a double-lumen catheter. At least two lumens are necessary because most children proceed to stem cell transplantation, in which intensity of treatment and blood product support necessitate multilumen vascular access.

Splenectomy is restricted to patients with severe hypersplenism and disease that is unresponsive to other treatment modalities.

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