Normal platelet count =1.5 - 4.5 lac per cu.mm 35% of patients with thrombocytosis eventually end up being Diagnosed with Malignancy Causes of Thrombocytosis Tissue inflammation: collagen vascular disease, inflammatory bowel disease Hemorrhage Malignancy Iron-deficiency anemia Infection Surgery Myeloproliferative disorder: polycythemia Vera, primary myelofibrosis, chronic myelogenous leukemia Rebound: Correction of vitamin B12 or folate deficiency, post-ethanol abuse Myelodysplastic disorder: 5q- syndrome, idiopathic refractory sideroblastic anemia Hemolysis Post splenectomy or hypersplenism Familial: Thrombopoietin overproduction, JAK21 or MPL mutations