Abstract
BACKGROUND: Hyperhemolysis syndrome (HS) is a severe hemolytic transfusion reaction that can cause hemoglobin and hematocrit levels to drop below pretransfusion levels, leading to severe anemia. HS most commonly occurs in patients with a pre-existing hemoglobinopathy such as sickle cell disease (SCD) or beta-thalassemia. METHODS: We report a case of HS, occurring in the absence of hemoglobinopathy, making the diagnosis challenging. The patient reported was also affected by a CIC-rearranged sarcoma. As part of the workup, the patient received a bone marrow biopsy for suspected hemophagocytic lymphohistiocytosis. RESULTS: This provided a rare biopsy specimen to correlate reticulocytopenia with marked erythroid hyperplasia in the marrow, supporting the hypothesis of reticulocyte destruction as a contributing cause of anemia in these patients. This patient had demonstrable alloantibodies to the Jk(a) and P1 antigens as potential triggers for HS. CONCLUSIONS: It is vital that a diagnosis of HS be correctly made in these patients with severe anemia, as blood transfusions generally lead to worsening of their conditions.