Acquired Amegakaryocytic Thrombocytopenia in Adult-onset Still's Disease: Successful Combination Therapy with Tocilizumab and Cyclosporine.

Adult-onset Still's disease (AOSD) sometimes demonstrates hematologic disorder, whereas acquired amegakaryocytic thrombocytopenia (AAT) involvement is extremely rare. We herein report a 67-year-old woman with relapse of AOSD who concomitantly developed AAT. Thrombocytopenia along with high disease activity of AOSD was resistant to high-dose prednisolone, even in combination with methotrexate and tacrolimus. However, alternative treatment with cyclosporine after administering tocilizumab resulted in the improvement of thrombocytopenia, ultimately demonstrating that combination therapy based on suppressing the intractable disease activity of AOSD and subsequently adding a reliable immunosuppressant was required to achieve remission.