Long segment spinal epidural extramedullary hematopoiesis.

BACKGROUND

Extramedullary hematopoiesis is defined as the formation of blood cells outside the bone marrow. It is a common manifestation of many chronic hemolytic anemias, and typically involves the liver, spleen, and lymph nodes. Only rarely is the spinal epidural space involved.

METHODS

We describe a 25-year-old male, known to have thalassemia intermedia, who presented with a 1-month history of stiffness and weakness in both lower extremities. On physical examination, he had palpable splenomegaly accompanied by spinal tenderness at the D5 level, weakness in both lower extremities, hyperactive bilateral Patellar and Achilles reflexes with bilateral Babinski responses, and a graded sensory loss to pin appreciation below D5.

RESULTS

The magnetic resonance (MR) study revealed a posterior, isointense and soft tissue epidural mass extending from D2 to D12 on both the T1- and T2-weighted images. These findings were consistent with the diagnosis of "red marrow," and long-segment spinal epidural extramedullary hematopoiesis.

CONCLUSIONS

Although extramedullary hematopoiesis is rarely encountered within the spinal canal, it should be considered among the differential diagnoses when a posterior compressive thoracic lesion contributes to myelopathy in a patient with a history of thalassemia intermedia and the accompanying chronic hemolytic anemia.