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Table: Laboratory Findings Associated with Myeloproliferative Neoplasms (MPNs)

The table below summarizes the laboratory findings that are often associated with the myeloproliferative neoplasms discussed in this course.

Peripheral Blood Abnormalities
Bone Marrow Abnormalities
Possible Genetic Abnormalities
Chronic myelogenous leukemia
Three phases:
  • Chronic
  • Accelerated
  • Blast
Chronic phase
  • WBC count may be over 100 x 109/L with left shift
  • Increased platelet count
  • Reduced RBC count; moderate anemia
  • Blasts <20%
  • Low LAP* score
Accelerated phase
  • Nonresponsive, very high (>1000 x 109/L) or low (<100 x 109/L) platelet count
  • Steadily increasing WBC count
  • >20% basophils
Blast phase
  • >20% blasts
  • High myeloid:erythroid ratio (50:1)
  • <20% blasts during chronic phase
  • Dysplastic development of megakaryocytes or granulocytes during accelerated phase
  • Fibrosis during the blast phase
  • Philadelphia chromosome
  • BCR/ABL1 fusion gene
  • Development of additional genetic abnormalities during accelerated phase
Serum uric acid and lactate dehydrogenase are often increased due to the rapid cell turnover.
CML is associated with an eventual transformation into acute myelogenous leukemia (AML) or acute lymphoblastic leukemia (ALL).

Chronic neutrophilic leukemia
  • Elevated neutrophil count(80% or more of WBCs)
  • <10% immature granulocytes
  • <1% blasts
  • Hypercellular
  • Dysplasia and fibrosis usually not present
  • Few abnormalities
  • Possible clonal karyotypic abnormalities such as +8, +9, del (20q) and del (11q)
Diagnosed on the basis of excluding other myeloproliferative disorders and reactive neutrophilia.
Chronic eosinophilic leukemia (CEL)
  • WBC count >30 x 109/L
  • 30-70% of WBCs are eosinophils
  • Fibrosis is common
  • Increased eosinophils
  • No single or specific genetic abnormality has been identified
Rare subtype of hypereosinophilic syndrome.
To make a diagnosis of CEL, there should be evidence for clonality of the eosinophils or an increase in blasts in the blood or bone marrow.
Essential thrombocytosis
  • Platelet count typically >600 x 109/L, often >1000 x 109/L
  • Giant, bizarre platelets
  • Platelet clumps
  • Megakaryocytes
  • WBC and RBC counts may also be elevated
  • Hypercellular
  • Over-proliferation of megakaryocytes
  • Giant megakaryocytes
  • clusters of megakaryocytes
  • Other dysplastic megakaryocytic changes
  • JAK2(V617F)mutation in about half of cases
Other findings include:
  • Normal or slightly increased thrombopoeitin
  • Usually normal prothrombin time (PT) and activated partial thromboplastin time (aPTT)
  • Platelet aggregation: abnormal with adenosine diphosphate, epinephrine, and collagen
  • Increased serum cobalamin, uric acid, LD, acid phosphatase

Primary myelofibrosis
  • Immature WBCs
  • Immature RBCs
  • Abnormal RBC morphology: Tear drop cells
  • Normocellular or hypocellular
  • Moderate to marked fibrosis
  • JAK2(V617F) mutation in about 60% of cases
    Extramedullary hematopoiesis occurs due to fibrin hindering normal functioning of the bone marrow.
      Splenomegaly is a common and important finding.
      Bone marrow aspiration may be unsuccessful ("dry tap") due to fibrous tissue blocking access to blood in the bone marrow cavity.
        Polycythemia vera
        • RBC count > 6.0 x 1012/L
        • Hemoglobin >16.5 g/dL (females); >18.5 g/L (males)
        • Hematocrit >48% (females); >52% (males)
        • WBC count >12.0 x 109/L
        • Platelet count >450 x 109/L
        • Hypercellularity
        • Prominent erythroid, granulocytic, and megakaryocytic proliferation
        • JAK2(V617F) gene mutation in >95% of cases
          Serum erythropoietin level is below the normal range.

            Two general forms
            • Cutaneous (skin involvement)
            • Systemic (organ/tissue involvement)
            • Large numbers of atypical mast cells if systemic mastocytosis progresses to mast cell leukemia (MCL)
            • Infiltrates of mast cells
            • Atypical and/or immature mast cells in bone marrow biopsy and aspirate smear
            • Majority of patients with systemic mastocytosis possess the genetic mutation D816V in the KIT gene
            MCL is a rare condition. Approximately 15% of patients with malignant mastocytosis develop MCL.
            Myeloproliferative neoplasm, unclassifiable (MPN-u)
            • WBC and platelet counts typically increased
            • RBC counts variable
            • Increased megakaryocyte proliferation
            • Variable hypercellularity in granulocytic or erythrocytic cell lines
            • Increasing bone marrow fibrosis can occur with the progression of the disease
            • No defined cytogenetic abnormalities
              MPN-u may actually be a very early stage or a very late transformational stage of one of the other MPNs listed above.

                *leukocyte alkaline phosphatase