Large lobar intracerebral hemorrhage revealing an occult JAK2 V617F-positive myeloproliferative neoplasm: A case report

Large lobar intracerebral hemorrhage revealing an occult JAK2 V617F-positive myeloproliferative neoplasm: A case reportTo the Editor, Philadelphia chromosome-negative myeloproliferative neoplasms (MPNs) are clonal myeloid disorders characterized by persistent overproduction of one or more blood-cell lineages.These disorders are commonly driven by JAK2 V617F and are associated with both thrombotic and hemorrhagic complications.1,2 Intracerebral hemorrhage (ICH) as the initial clue to an otherwise occult MPN has only rarely been reported.3,4 We report a large lobar ICH requiring emergency evacuation in which preoperative multilineage blood-count abnormalities led to the diagnosis of a JAK2 V617F-positive MPN.The subsequent postoperative deepvein thrombosis further illustrated the competing hemorrhagic and thrombotic risks relevant to surgical care.A 73-year-old man with no previous bleeding or thrombosis and no exposure to antiplatelet or anticoagulant agents presented 5 hours after the onset of impaired consciousness.His Glasgow Coma Scale score was 8 (E2V3M3), and his blood pressure was 154/80 mmHg.Computed tomography showed a 65 × 46 × 80mm left temporoparieto-occipital hematoma with ventricular compression and mild midline shift (Fig. 1A).Magnetic resonance