Case of the Week
Section Editors: Matylda Machnowska1 and Anvita Pauranik2
1University of Toronto, Toronto, Ontario, Canada
2BC Children's Hospital, University of British Columbia, Vancouver, British Columbia, Canada
Sign up to receive an email alert when a new Case of the Week is posted.
February 21, 2019
Extramedullary hematopoiesis
- Background
- Extramedullary hematopoiesis (EH) is a physiological response to chronic anemia. It occurs in hematological diseases such as thalassemia, sickle cell anemia, etc. The most common sites of ectopic hematopoietic tissue are the liver, spleen, and lymph nodes. The involvement of the epidural space associated with spinal cord compression is a rare condition associated with high morbidity.
- Clinical Presentation
- Back pain, radicular symptoms; neurological deficits may occur if the cord is compressed, with predilection for the thoracic region. Laboratory evaluation is also of main importance, showing microcytic anemia.
- Key Diagnostic Features
- Epidural and paravertebral lobulated masses following the signal intensity of the bone marrow. Abnormal signal intensity of bony elements without morphological changes.
- Differential Diagnosis
- Metastasis, lymphoma: may have focal bone destruction.
- Multiple meningiomas, multiple nerve sheath tumors: Typical appearance of dural tail of enhancement (meningioma) or dumbbell morphology (nerve sheath tumor), would not be associated with diffuse marrow signal abnormality.
- Epidural abscess: often associated with concomitant spondylodiscitis or paraspinal abscess.
- Epidural hematoma: hyperintense T1 signal, rapid onset of symptoms.
- History of a chronic hemoglobinopathy would strongly suggest the correct diagnosis.
- Treatment
- There is no standard therapeutic approach, with control of the primary disease being most essential. Transfusion therapy, radiotherapy, surgery, use of drugs such as hydroxyurea/steroids or a combination of modalities, are all potential management options.
- Radiotherapy is effective as a primary treatment, because hematopoietic tissue is known to be extremely radiosensitive.
- Cytoreductive therapy with hydroxyurea is particularly useful to thalassemic patients who are unable to received blood transfusions due to alloimmunization. Blood transfusions should be used in concert with other modalities, because of high recurrence rates.
- Surgery provides rapid decompression, preventing permanent damage in patients with spinal cord compression syndrome, but risks such as cord injury and the difficulty of complete resection, are important disadvantages compared to other treatment options, so generally this is limited to cases of hemorrhage or very rapid neurologic decline.
Current Issue
Case Collections
