Spinal cord compression (SCC) is an unusual sequale of extra-medullary hematopoiesis (EMH). We report a patient diagnosed with β-thalassemia intermedia at the age of 7 years presenting as a 24-year-old with symptoms suggestive of paraparesis. MR imaging revealed long masses of EMH opposite T5-T11 and L5-S2 vertebrae with cord compression at T6 vertebrae. Patient was treated with external beam radiotherapy (EBRT) to a low dose of 20 Gy in 10 fractions over 2 weeks. The patient had symptomatic relief of paraparesis by the 5th fraction and nearly regained full power in bilateral lower limbs by EBRT conclusion. Patient was begun on hydroxyurea post EBRT and was symptom free at 2-month follow up. With a follow-up of 18 months so far, he remains asymptomatic and free of recurrence. MRI correlation of pre-EBRT, post-EBRT and at first follow-up showed a significant reduction in the size of EMH, increase in diameter of spinal canal post EBRT but a persistent edema which had no clinical manifestation. Though there was a 58% drop in leukocyte count by the end of EBRT, there was no leukocytopenia. We suggest that EBRT should be treatment of choice for SCC due to EMH as it produces as rapid and durable response with minimal acute hematological side-effects.
Keywords: Radiotherapy; extramedullary hematopoiesis; spinal cord compression; thalassemia.