Polycythemia-linked Cerebral Venous Thrombosis with Right Fronto-TemporoParietal Infarct: A Case Report

Cerebral Venous Thrombosis (CVT) is a rare form of stroke, often linked to prothrombotic states, inducing Philadelphia-negative Myeloproliferative Neoplasms (MPN) such as Polycythemia Vera (PV) and Essential Thrombocythemia (ET), which predispose via hyperviscosity and Janus Kinase-2 (JAK2)-mediated platelet activation. We report a unique case of CVT in a 65-year-old hypertensive woman, an atypical demographic compared to the usual population, with chronic headaches developed four days of left lower limb weakness. Neuroimaging revealed a superior sagittal and right transverse sinus thrombosis with a non-haemorrhagic frontotemporo-parietal infarct. Laboratory evaluation demonstrated leukocytosis (14×103/μL), thrombocytosis (739×103/μL), alongside JAK2-V617F positivity. This constellation of findings places her phenotype between ET and PV. Reflex JAK2 testing enabled early provisional diagnosis of MPN-associated CVT despite the absence of marrow biopsy. Prompt anticoagulation with LowMolecular-Weight Heparin (LMWH) was transitioned to apixaban 5 mg twice daily, and achieved marked neurological improvement by discharge. This case highlights the rarity of CVT in an older hypertensive patient with JAK2-positive MPN but no erythrocytosis, and underscores the importance of reflex mutation screening and timely anticoagulation in achieving favourable outcomes.