Acute paraplegia due to thoracic extramedullary hematopoiesis in chronic myeloproliferative disorder--an unusual presentation.

Spinal cord compression due to extramedullary hematopoiesis is a well-known complication in a number of hematological diseases. Most of the patients present with progressive paraparesis due to the slow expansion of the extramedullary hematopoietic tissue. The authors report a case of chronic myeloproliferative disorder with spinal extramedullary hematopoiesis presenting with acute paraplegia. Chronic myeloproliferative disorder is an uncommon cause of spinal cord compression, especially when associated with acute paraplegia. The authors discuss the pathomechanism of this unusual presentation.