Myeloproliferative disorders are a heterogenous group of disorders which result from clonal neoplastic proliferation of one or more myeloid stem cells. Each disorder produces a characteristic syndrome with well-defined clinical and laboratory features but they are grouped together since one disease may evolve into another and all may progress to acute myeloid leukaemia.
Specific types are named according to the predominant differentiation pathway followed:
- chronic myeloid (granulocytic) leukaemia - myeloid differentiation
- polycythaemia vera - erythroid differentiation
- essential thrombocythaemia - platelet differentiation
- myeloid metaplasia with myelofibrosis - multilineage differentiation with marrow fibrosis