• Neoplastic stem cell proliferation, Slow, Chronic.
• increased Tyrosine kinase activity due to JAK2 activation on short arm chromosome 9p*, PDGF mutations → growth factor hypersensitivity. (BCR-ABL in CML).
• Slow proliferation with maturation. increased number (abnormal) of cells, Hepatosplenomegaly.

<aside> 💡 All can transform to Acute Leukemia (AML) / Myelofibrosis after years. through chemical mediators of fibrosis

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Classification

1. Polycythaemia vera (PV) - RBC
2. Chronic Myeloid Leukemia (CML) - WBC
3. Essential Thrombocythemia (ET) - Platelet
4. Myelofibrosis (MF) – Fibroblasts

Mixed – common.

Polycythaemia Rubra Vera (PV)

Essential Thrombocythemia (ET)

Primary Myelofibrosis