Myeloproliferative disorders

Myeloproliferative disorders
They describe the inter-relationship exist between acute and chronic myeloid leukemias. They include:
1. Polycythemia rubra vera (primary polycythemia).
2. Essential thrombocythemia (primary thrombocytosis).
3. Myelofibrosis.

In early stages of MPD, the following features are seen:
• Generalized bone marrow proliferation with extension to long bones of limbs.
• Large number of marrow megakaryocytes which often have abnormal nuclei and occur in clusters.
• Increase fine fibrillar reticulin and sometimes, there is collagen deposition.
• Platelets dysfunction.

Polycythemia
It is a raised packed cells volume (PCV) above 51% in males and 48% in females. It is classified into:
• Absolute polycythemia : raised red cells mass.
1. Primary polycythemia.
2. Secondary polycythemia.
3. Idiopathic erythrocytosis.
• Apparent polycythemia: red cells mass is within normal.

Diagnostic criteria of polycythemia rubra vera (primary):
1. Red cell mass more than 25% above mean normal predicted value.
2. No evident cause for secondary polycythemia (with arterial O2 saturation above 92%).
3. Palpable splenomegally.
4. Evidence of clonal disorder e.g. abnormal marrow karyotype.