Spinal cord compression due to extramedullary hematopoiesis in the proliferative phase of polycythemia vera.

Extramedullary hematopoiesis is a common accompaniment of a variety of hematologic diseases such as hereditary spherocytosis, thalassemia and myelofibrosis. The association of extramedullary hematopoiesis with polycythemia vera in the proliferative phase is much less usual. We report a patient who presented with paraplegia due to spinal cord compression; clinical investigation revealed a paravertebral hematopoietic tumor, and the diagnosis of polycythemia vera was then established.