Myeloproliferative Neoplasms

Definition

A group of non-leukemic clonal stem cell diseases characterized by uncontrolled marrow proliferation due to tyrosine kinase activating mutations

Disease	Tyrosine Kinase Affected	Peripheral Blood	Marrow Cell Lines Affected	Marrow Fibrosis
CML	ABL	Leukocytosis with increased basophils & Igs	Markedly increased myeloids	Variable
Polycythemia Vera	JAK2	Normo- or hypochromic anemia, may have increased platelets & basophils	Panmyelosis, variable erythroid hyperplasia, atypical megakaryocytes	Increased in spent phase
Essential Thrombocythemia	JAK2 or MPL	Platelets increased, frequently abnormal	Markedly increased megakaryocytes	Minimal
Primary Myelofibrosis	JAK2 or MPL	Leukoerythroblastic, teardrop RBCs	Panmyelosis, atypical megakaryocytes	Increased in fibrotic phase
Chronic Neutrophilic Leukemia	JAK2 rare	Increased, normal granulocytes	Granulocytic hyperplasia	None
Chronic Eosinophilic Leukemia, NOS	None	Eosinophilia	Eosinophilic hyperplasia with maturation	Occasional
Hematolymphoid Neoplasms with Eosinophilia & Specific Tyrosine Kinase Abnormalities	PDGFRA, PDGFRB, FGFR1	Eosinophilia	Eosinophilic hyperplasia with maturation	May be increased
Mastocytosis	KIT	Variable	Variable	Frequent
Myeloproliferative Neoplasm, Unclassifiable	None	Variable	Variable	Variable

Dita Gratzinger MD PhD
Tracy I George MD
Department of Pathology
Stanford University School of Medicine
Stanford CA 94305-5342