Extramedullary hematopoiesis in Paget's disease of bone.

Two cases of Paget's disease of bone with radiographic manifestation of extramedullary hematopoiesis are described. While extramedullary hematopoiesis usually occurs as compensatory phenomenon in response to anemia, this was not the case in our patients. We believe pathologic fractures led to extrusion of hematopoietic marrow and resultant tumorous extramedullary hematopoiesis.