Polycythemia vera

Clinical Manifestations

• Elevated hemoglobin and hematocrit
  • Possibly mild leukocytosis and thrombocytosis
• Hypertension (45%)
• Splenomegaly (35%)
• Pruritus (35%), particularly after water exposures
• Erythromelalgia (30%)
• Arterial (15%) and venous (5-10%) thrombosis
• Also: facial plethora, hepatomegaly

Investigations

• CBC
  • Hemoglobin greater than 185 (73%)
  • WBC greater than 10.5 (49%)
  • Platelet count greater than 450 (53%) or 1000 (4%)
  • Leukoerythroblastic reaction on blood film (6%)
• Elevated serum LDH (50%)
• JAK2 mutation positive (98%)
• Abnormal karyotype (12%)
• Low serum erythropoietin level (81%)

WHO Diagnostic Criteria

• Major criteria
  • Polycythemia, as evidenced by one of:
    • Hemoglobin >16.5 g/dL in men or >16.0 g/dL in women
    • Hematocrit >49% in men or >48% in women
    • Increased red cell mass more than 25% above reference range
  • Bone marrow biopsy showing hypercellularity for age with trilineage growth (panmyelosis) including prominent erythroid, granulocytic, and megakaryocytic proliferation with pleomorphic, mature megakaryocytes (differences in size)
  • Presence of JAK2 V617F or JAK2 exon 12 mutation
• Minor criterion
  • Subnormal serum erythropoietin level
• Diagnosis of PV requires meeting either all 3 major criteria, or the first 2 major criteria and the minor criterion¶