[Essential thrombocythemia complicated by intracranial thrombohemorrhagic events].

Although the life expectancy if patients with essential thrombocythemia (ET) is considered to be almost similar to that of the general population, advanced age, leukocytosis, and a previous history of thrombosis are poor prognostic factors, and it is important to prevent thrombohemorrhagic events, leukemic transformation, and secondary malignancies. We report an 85-year-old ET patient with a history of asymptomatic lacunar infarction, who developed symptomatic cerebral infarction and even chronic subdural hematoma. It is necessary to follow patients who have asymptomatic cerebral infarction or chronic ischemic change and to examine the necessity of brain imaging and treatment intervention at the time of diagnosis.