Myelodysplastic syndrome: Meaning (information, definition, explanation, facts)

The myelodysplastic syndromes are a collection of haematological conditions including:

• Refractory anaemia (RA)
• Refractory anaemia with ring sideroblasts (RARS)
• Refractory anaemia with excess of blasts (RAEB)
• Chronic myelomonocytic leukaemia (CMML) - not to be confused with CML

All the conditions show abnormalities in the production of one or more of the cellular components of blood (red cells, white cells (other than lymphocytes) and platelets (or their progenitor cells, megakaryocytes).

Signs and symptoms

These abnormalities include:

• neutropenia, anaemia and thrombocytopenia (low cell counts of each)
• abnormal granules in cells, abnormal nuclear shape and size
• chromosomal abnormalities, including chromosomal translocations.

Symptoms of myelodysplastic conditions:

• Anaemia - chronic tiredness (in this condition blood transfusion is the only effective treatment, which can carry on for years)
• Neutropenia (low white cell count) - increased susceptibility to infection
• Thrombocytopenia (low platelet count) - increased susceptibility to bleeding

Because the cellular function is impaired the effects of low cell counts may be greater than in other conditions with a similar cell count be less impairment of normal function.

All these conditions have an increased risk of developing acute leukaemia, which is notoriously resistant to treatment ("secondary leukaemia"). In RA and RARS the risk is relatively low and the condtion may persist for many years (eg 10). In RAEB and CMML the time course is typically quicker.

Investigation:

• Full blood count and examination of blood film
• Bone marrow aspirate
• In some cases: chromosome studies.

These are mostly conditions of the elderly. However, there is an increased risk in those people who have had chemotherapy for other tumours.

Treatment:

1. No treatment (watch and wait)
2. Conservative (eg periodic blood transfusion)
3. Chemotherapy (although often patients do not tolerate chemotherapy well).