Disorder	Diagnostic Features	Mutation
Chronic myelogenous leukemia	Constitutional symptoms (e.g., fatigue, weight loss, excessive sweating), splenomegaly & leukocytosis with marked left shift (e.g., myelocytes, metamyelocytes, band forms)	Philadelphia chromosome t(9:22), BCR-ABL fusion protein
Essential thrombocytosis	Hemorrhagic & thrombotic symptoms (e.g., easy bruising, microangiopathic occlusion), thrombocytosis & megakaryocytic hyperplasia	JAK2
Polycythemia vera	Pruritus, erythromelalgia, splenomegaly, thrombotic complications, erythrocytosis & thrombocytosis	JAK2
Primary myelofibrosis	Severe fatigue, splenomegaly (often causing early satiety/abdominal discomfort), hepatomegaly, anemia & bone marrow fibrosis	JAK2