Which of the following is associated with autonomous process thrombocytosis?

Autonomous process thrombocytosis is characterized by an increase in platelet production that occurs independently of the body's normal regulatory mechanisms. This condition is often associated with conditions that lead to excessive or abnormal proliferation of megakaryocytes in the bone marrow. Essential thrombocythemia is a myeloproliferative neoplasm where there is a clonal increase in megakaryocytes, leading to thrombocytosis. Patients with essential thrombocythemia often have persistently elevated platelet counts and may be at increased risk for thrombotic or hemorrhagic complications.

In contrast, hypersplenism, malignancy, and iron deficiency are typically associated with secondary causes of thrombocytosis. Hypersplenism can lead to sequestration of platelets and usually results in a decreased platelet count rather than an increase. Malignancies can indirectly influence platelet levels, but they are not necessarily characterized by autonomous production of platelets. Iron deficiency can lead to a reactive increase in platelets (reactive thrombocytosis) as a response to systemic inflammation, rather than an independent enhancement of platelet production. Therefore, essential thrombocythemia is the condition directly associated with autonomous process thrombocytosis.