[Symptomatic extramedullary haematopoiesis in β-thalassemia: A retrospective single centre study]

Symptomatic extramedullary hematopoiesis (EH) is a rare but potentially severe phenomenon which occurs in β-thalassemia. There are no treatment guidelines.

Retrospective single centre study including the cases of symptomatic EH encountered between 1997 and 2014 in a unit specialised in red blood cell genetic disorders. Description of clinical, biological and radiological characteristics of the patients, treatments received, and outcomes.

Among 182 β-thalassemia patients followed during the study period, 7 cases of symptomatic EH were diagnosed. They were 5 men and 2 women, and their mean age was 37 years. Four patients were splenectomised, two patients were regularly transfused, and four patients had already received erythropoietin. EH was localised in intravertebral areas and responsible for dorsal spinal cord compression in 5 patients, in paravertebral dorsal area in 1 patient, and in presacral area in 1 patient. The mean hemoglobin level at diagnosis was 7.9 g/dL. Treatment administered included: red cell transfusion in 6 cases, associated with hydroxyurea in 5 cases and/or radiotherapy in 3 patients. One patient was treated with surgery and HU. After a median follow-up of 41 months, clinical recovery was complete in 2 patients and partial in 5 patients.

EH must be suspected in β-thalassemia in patients presenting clinical signs of organ compression, and a typical radiological aspect. The functional prognosis depends on the rapidity of treatment, which includes red blood cell transfusion, hydroxyurea, radiotherapy, and rarely surgery. Long-term outcome is uncertain.