Cancer-associated thromboembolism is not an uncommon complication in patients with malignancies. No study has reported the occurrence of thromboembolism prior to the diagnosis of acute myeloid leukemia (AML). Most reports are anectodal and data are scarce on this subject. In this report, we present a case of extensive cerebral venous thrombosis (CVT) that was detected a few weeks before the diagnosis of AML, in which case the patient responded well to chemotherapy and anticoagulation.