In addition to the acute myeloid leukemias , myelodysplastic syndromes, myelodysplastic/myeloproliferative neoplasms and the myeloid/lymphoid neoplasms with eosinophilia and rearrangement of PDGFRA, PDGFRB, or FGFR1, or with PCM1-JAK2, the myeloproliferative neoplasms are part of the myeloid neoplasms. In MPS, clonal diseases of the pluripotent hematopoietic stem cells lead to an autonomous proliferation of bone marrow cells. These are functionally and morphologically almost normal blood and bone marrow cells. All cell lines are affected but one predominates thereby producing the clinical picture.
The four classical myeloproliferative syndromes are:
1. Chronic myelocytic leukemia (CML), predominant granulopoiesis
2. Myelofibrosis (MF), predominant fibrosis
3. Polycythemia vera (PV), predominant erythropoiesis
4. Essential thrombocythemia (ET), predominant megakaryocytopoiesis
In the newer WHO classifications, the following two disease are also part of the MPNs.
5. Chronic eosinophilic leukemia
6. Chronic neutrophilic leukemia
According to the WHO 2016-classification, the systemic mastocytosis is no longer part of the MPNs. It is now considered to be an entity of its own.
Lab results in the 4 classical MPN:
|Hemoglobin / hematocrit||N / ↓||↓||+++||N|
|Leukocyte count||+++||N /+ /++ / ↓||N / +||N / +|
|Platelet count||+ / N||N /+ /↓||N / +||+++|
|Immature myeloid cells||+++||+||rare||rare|
|Basophilia / eosinophilia||+ / +++||+ / ++||+||rare|
|Extramedullary blood formation||rare||frequent||rare||rare|
|Spleen size||+/ ++||+++||+ / ++||N / +|
Bone marrow fibrosis
|N / +||++/+++||N / +||N / +|
|Transition to acute leukemia||obligatory||occasionally||rare||rare|
Key: N = normal; +, ++, +++ = increased or enlarged; - = decreased.