Background Cerebral venous sinus thrombosis (CVST) is a rare but potentially life-threatening subtype of stroke. Prompt and appropriate anticoagulation is crucial for improving the prognosis of CVST and preventing its recurrence. Identifying the underlying cause of CVST is decisive for guiding anticoagulant selection and determining treatment duration. Case Presentation A 50-year-old man presented with a 35-day history of headache, nausea, vomiting, and blurred vision. Digital subtraction angiography performed at another facility revealed CVST. A contrast-enhanced black-blood MRI at our center confirmed the diagnosis, which was supported by a high intracranial pressure of 330mmH(2)O. Laboratory tests showed elevated leukocytes and platelet counts, raising suspicion of an underlying myeloproliferative neoplasms (MPNs). A bone marrow biopsy demonstrated increased megakaryocytes and granulocytes, and genetic testing identified the presence of the Janus kinase 2 V617F (JAK2 V617F) mutation, leading to a diagnosis of pre-primary myelofibrosis (pre-PMF). During hospitalization, anticoagulation with nadroparin calcium and fibrinolytic therapy were initiated. Upon discharge, rivaroxaban and aspirin were prescribed to prevent CVST recurrence and arterial thrombosis. Conclusion This case highlights the importance of recognizing dynamic changes in routine blood tests that may link CVST to underlying hematological disorders. The JAK2 mutation is not only associated with MPNs but also increases the risk of thrombosis, including CVST. Further investigation is warranted to better understand the mechanisms by which JAK2 mutations contribute to thrombosis and to explore the potential benefits of JAK2 inhibitors in reducing this risk.