Myeloproliferative syndromes (MPS)

Abstract:
In addition to the leukemias and myelodysplastic syndromes, the myeloproliferative syndromes are part of the neoplastic diseases of bone marrow. In MPS, clonal diseases of the stem cells lead to an autonomous proliferation of bone marrow cells. All cell lines are affected but one predominates thereby producing the clinical picture.

Classification:
The myeloproliferative syndromes include:
1. Chronic myelocytic leukemia (CML), predominant granulopoiesis
2. Myelofibrosis (MF), predominant fibrosis
3. Polycythemia vera (PV), predominant erythropoiesis
4. Essential thrombocythemia (ET), predominant megakaryocytopoiesis

	CML	MF	PV	ET
Hemoglobin / hematocrit	N or -	(-)	+++	N or -
Leukocyte count	mostly +++	N, + or ++	N or +	N or +
Platelet count	+ or N	N, + or -	N or +	+++
Immature myeloid cells	+++	++	rare	+
Basophilia / eosinophilia	+ to +++	+ or ++	+	(+)
Extramedullary blood formation	rare	frequent, tear drop cells	rare	rare
Leukocyte alkaline phosphatase	-	+ or N	+	N or +
Philadelphia chromosome (bcr-abl)	pos.	neg.	neg.	neg.
Spleen size	+ to +++	+++	+ or ++	N or +
Bone marrow fibrosis	N or +	+ to +++	N or +	N or +
Transition to acute leukemia	obligatory	rare	rare	rare

Legend: N = normal; +, ++, +++ = increased or enlarged; - = decreased.