Extramedullary hematopoiesis simulating parasagittal meningioma.

We report a patient with polycythemia vera and myeloid metaplasia of nine years duration who developed raised intracranial pressure related to a mass obliterating the sagittal fissure. Although clinically and radiologically simulating a meningioma, biopsy revealed extramedullary hematopoiesis involving the falx cerebri. Although uncommon, this case illustrates that myeloproliferative disease can present with symptomatology and radiologic features similar to primary intracranial tumours.