Intracranial involvement in extramedullary hematopoiesis: case report and review of the literature.

Intracranial involvement in extramedullary hematopoiesis (EMH) is rare, but it should be suspected in patients with myelofibrosis presenting with chronic severe headache. We present a 9-year-old girl with known myelofibrosis whose headaches were unresponsive to routine treatment. CT and MRI studies of the brain showed diffuse pachymeningeal thickening. CT examinations of the chest and abdomen had demonstrated bilateral thoracic paraspinal masses caused by EMH, suggesting the possibility that the intracranial involvement might also be related to EMH. The diagnosis was confirmed by sulfur colloid isotope scan.