Extramedullary haematopoiesis in beta thalassaemia--unusual presentations: case reports.

Extramedullary haematopoiesis (EH) refers to the production of blood cells outside the bone marrow as a compensatory mechanism for bone marrow dysfunction. It occurs in conditions with hyperactive, depleted or infiltrated marrow. The most frequent cause of EH is thalassaemia intermedia, due to increased demand on the hematopoietic system from anemia not reduced by transfusion therapy. The usual localizations are adjacent to bone. We report three unusual cases and discuss the current treatment.