Intracranial Extramedullary Hematopoiesis Simulating a Subdural Hematoma: A Case Report.

A 68-year-old patient came to the emergency department complaining of headaches and general weakness for the past month. The patient is known to have myeloproliferative disease. Non-contrast computer tomography showed a hyperdense extra-axial collection in bilateral frontoparietal regions, which was presumed to be bilateral subdural hematoma as the initial diagnosis. A drainage procedure using a borehole was performed, and a solid substance was aspirated instead of blood. Subsequently, the diagnosis of an extramedullary hematopoiesis was made using histopathological and immunohistochemical techniques.