Intracranial myeloid metaplasia in myelofibrosis.

In a man aged 62 years with a 14-year-history of polycythaemia vera progressing into a myelofibrotic stage symptoms and signs of an intracranial tumour with increased intracranial pressure developed. CT scan as well as angiography of the right internal carotid artery revealed richly vascularized masses within the meninges. The patient died in endocarditis and progressive heart failure and at autopsy the intracranial masses were shown to be due to meningeal myeloid metaplasia. The literature is reviewed and it appears that myeloid metaplasia within the central nervous system might be more common than has been hitherto anticipated. A CT scan is to be recommended in myelofibrosis whenever symptoms and signs suggesting intracranial disease are present.