DAT negative warm autoimmune haemolytic anaemia secondary to a mature cystic teratoma refractory to immunosuppressive therapy.

Mature cystic teratomas (MCTs) have a rare but recognised association with IgG-mediated autoimmune haemolytic anaemia (AIHA). We present the first case of an MCT associated with IgA-mediated AIHA. We discuss the diagnostic challenges of patients presenting with a direct antiglobulin test negative AIHA picture and the importance of reviewing these cases with the local transfusion laboratory. We also review the treatment options for MCT associated AIHA. In particular, we note they are typically resistant to immunosuppression and that surgical resection should be considered at an early stage. Although MCTs are a rare cause of AIHA, they can be treated easily and should be excluded in young women presenting with AIHA, especially if resistant to corticosteroids.