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222 / Chapter 16 Myelodysplasia

rash, hepatosplenomegaly and lymphadenopathy. drome and neurofibromatosis, are at increased risk

9

There is a monocytosis to > 1.0 × 10 /L and clonal of juvenile myelomonocytic leukaemia (JMML)
cytogenetic change. The only curative treatment is and mutations in the marrow of the genes PTPN11

allogeneic SCT. If untreated, death usually occurs and NF1 , which in the germline underlie these
within 4 years, often from acute transformation genetic disorders, are frequent in the bone marrow

’
with leukaemic infiltration (e.g. of the lungs). in cases of JMML not associated with Noonan s
’
Children with two genetic disorders, Noonan s syn- syndrome or neurofi bromatosis.

SUMMARY ■ Myelodysplasia includes a group of clonal ■ Scoring systems can divide patients in

They are classifi ed into eight major

disorders of haemopoietic stem cells that
subtypes.

lead to bone marrow failure and low blood

those with low - grade or high - grade
cell counts. A hallmark of the disease is
disease.

simultaneous proliferation and apoptosis of
■ Low - grade disease may not need

haemopoietic cells leading to the paradox

of a hypercellular bone marrow but
pancytopenia in peripheral blood. There is
lenalidomide or blood product support

may be useful when required.
a tendency to progress to acute myeloid treatment. Haemopoietic growth factors,

leukaemia. ■ High - grade myelodysplasia may be treated

■ In most cases, the disease is primary but it by intensive chemotherapy, demethylating
may be secondary to chemotherapy given drugs or stem cell transplantation.
for treatment of another malignancy. Allogeneic transplantation is the only

■ The main clinical features of anaemia, curative procedure.

infection and bleeding, are caused by ■ Myelodysplastic/myeloproliferative
reduction in the blood count. Most patients neoplasms are a group of disorders
are over 70 years of age. classifi ed between myelodysplasia and

■ Diagnosis is made by examination of myeloproliferative disorders and show the

the blood and bone marrow together presence of dysplastic features but also
with genetic studies of the tumour cells. increased number of circulating cells.
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