A meningioma with islets of extramedullary myeloid metaplasia: case report

Idiopathic myelofibrosis is a clonal stem cell disorder that leads to ineffective erythropoiesis accompanied by reactive myelofibrosis (bone marrow fibrosis). As a consequence, extramedullary hematopoiesis characteristically develops. The central nervous system is rarely affected; the spinal canal and the cranial meninges are generally the preferred locations. Extramedullary hematopoiesis within central nervous system primary tumors have already been reported but, to our knowledge, never before in a patient with evidence of idiopathic myelofibrosis.

A patient experiencing generalized idiopathic myelofibrosis developed a hemorrhagic intracranial meningioma containing islets of extramedullary myeloid metaplasia.

The tumor was radically removed through a right frontal craniotomy. After surgery, the patient recovered completely and was discharged with a normal neurological status. After 6 years, the patient is in excellent condition with no sign of recurrence on magnetic resonance imaging scans.

The reasons for this uncommon association are uncertain, but we hypothesize that myeloid islets may be involved in the origin of the tumor as well as in its acute hemorrhagic onset. Moreover, we suggest that in the presence of proven idiopathic myelofibrosis intracranial myeloid metaplasia should be ruled out by appropriate neuroimaging and considered as a potential diagnosis in the presence of brain lesions.