1. Extramedullary hematopoiesis as a potential pitfall for meningeal mass in patients with myelofibrosis
Ghimenton C1, Eccher A1, Brunelli M2, Gobbo S2, Parisi A1, Martignoni G2, Turazzi S3, Chilosi M2, Menestrina F2.
1 Anatomia Patologica, Ospedale Civile Maggiore, Verona
2 Dipartimento di Patologia, Università di Verona
3 Neurochirurgia, Ospedale Civile Maggiore, Verona

2. Introduction Myelofibrosis leads to ineffective erythropoiesis
Extramedullary hematopoiesis characteristically
develops predominantly in the spleen and liver
The central nervous system is rarely affected and the
spinal canal and the meninges are preferred locations

3. Case report 63 yrs woman with history of worsening headaches and
documented bone marrow fibrosis.
MR imaging revealed a bilateral, frontal-solid-lesion,
attached to the dura, that was hyperintense to contrast.
The patient underwent a frontal craniotomy
for suspected meningioma and the lesion was removed
with its dural implant.
Grossly the tumor resection measured in
aggregate cm 4,5x3,5x3.

4. MR imaging

5. Histological examination revealed multiple foci of hematopoietic
cells of erythroid, myeloid and megakaryocytic lineages confirmed
with stains for glycophorin, myeloperoxidase and Factor VIII.

6. AE1/AE3 GFAP The hematopoietic cells were of course immunonegative
for pankeratin and glial fibrillary acidic protein.
The diagnosis was meningeal EH.
AE1/AE3
GFAP

7. Discussion The presence of EH loci in primary brain tumors
is fairly rare
Extramedullary myeloid metaplasia should be ruled out
in patients experiencing idiopathic myelofibrosis and
considered as a differential diagnosis in brain lesions

8. References
A meningioma with islets of extramedullary myeloid metaplasia:
case report.
Zona G. et al, Neurosurgery 2007.
2. Intracranial extramedullary hematopoiesis associated with
pilocytic astrocytoma: a case report
Beckner E. et al, Acta Neuropathology 2003.