In essential thrombocythemia, how do the platelets typically present?

In essential thrombocythemia, a myeloproliferative neoplasm, the hallmark feature is the significant increase in platelet production. This condition is characterized by an elevated platelet count, often exceeding 450,000 platelets per microliter of blood. Not only are the platelets increased in number, but they can also exhibit functional abnormalities. These functional defects may manifest as increased bleeding risk, paradoxically, or thrombotic complications since the platelets may not function as effectively in hemostasis despite being present in high numbers.

The presence of increased and often abnormal platelet function is due to the underlying genetic mutations, commonly seen in essential thrombocythemia, such as JAK2 V617F. These mutations drive excessive megakaryocyte proliferation in the bone marrow, leading to the overproduction of platelets. Therefore, the correct description is that the platelets are both increased in number and can be functionally abnormal.