Case Presentation: A 23 yo Indian M with a history of transfusion-dependent β-thalassemia major, extramedullary hematopoiesis (EMH), iron overload, and myeloneuropathy presented with mid-back pain, bilateral lower extremity (BLE) weakness and pain with acute-on-chronic paresthesias, gait imbalance, and recent falls. He complained of constipation, but denied saddle paresthesia, urinary retention, or bowel incontinence. Symptoms progressively worsened after transfusion and treatment w/ luspatercept 10 days PTA.His exam was remarkable for 2/5 strength in BLE, loss of proprioception in bilateral toes, decreased sensation in BLE, hyperreflexia of BLEs w/o clonus, and + Romberg sign. He had normal rectal tone and no saddle anesthesia. The remainder of his physical exam was unremarkable. His only lab abnormality was a Hgb of 10.8, which was close to baseline. MRI showed diffuse EMH present throughout thoracic and lumbar spine causing spinal cord compression and edema w/i the midthoracic spine and cauda equina compression w/i the lower lumbar spine.Neurosurgery, Hematology, and Radiation Oncology were consulted. He was started on dexamethasone and underwent T4-T10 laminectomy and resection of epidural tumors for decompression of his thoracic spine. Pathology confirmed EMH. He also received post-surgical radiation to his lumbar and thoracic spine. He is receiving transfusion every three weeks with goal Hgb > 10.5 to prevent further EMH. He is no longer on luspatercept. He was discharged to acute rehab where he regained the ability to ambulate and is continuing to regain strength.

Discussion: β-thalassemia is a recessively inherited mutation of the β-globulin gene resulting in decreased β-globulin synthesis and chronic hemolytic anemia. Extramedullary hematopoiesis (EMH) is a compensatory mechanism where erythropoiesis occurs outside of the bone marrow to help overcome the effects of this chronic anemia. In rare cases, EMH occurs in the intraspinal epidural space and results in serious spinal cord compression. MRI is the preferred imaging for diagnosis and monitoring.Ideal treatment of spinal cord compression remains controversial but can consist of a combination of surgical decompression, low-dose XRT (since hematopoietic tissue is particularly radiosensitive), and hypertransfusion (goal Hgb > 10). Some reviews suggest surgery as a last resort only if hypertransfusion and XRT fail to alleviate symptoms. In our case, surgical decompression was needed urgently to prevent further neurologic deficits. Proton beam XRT was used given his young age, since reduced scatter dose from protons decreases the risk for acute and late toxicities and secondary malignancies from radiation.It is unclear whether the patient’s recent treatment w/ luspatercept contributed to his EMH and cord compression as these have not yet been reported as adverse reactions.

Conclusions: EMH causing severe cord compression, such as that diagnosed in our patient, is a rare but important complication of β-thalassemia of which hospitalists should be aware. Careful history and neurologic assessment are crucial to prompt recognition of this neurologic emergency. In our case, the patient attained prompt workup, early steroids, and surgical spinal decompression, which led to restoration of mobility in this young patient