Hairy cell leukemia and multiple myeloma: Two distinct entities or a single two-phase disease

Abstract

Hairy cell leukemia (HCL) and multiple myeloma (MM) originate from mature B-cell and they are characterized by different clinical symptoms and treatment. Their clinical outcome is also different. The introduction of 2-CdA makes HCL a potentially curable disease, but MM still remains incurable despite a therapeutic progress made in the recent years. We report a male patient who simultaneously developed HCL and MM. He was treated with combined therapy including 2-CdA and thalidomide and this approach resulted in complete remission (CR) of HCL and partial response (PR) of his MM. This patient continued MM treatment with CTD regimen (cyclophosphamide, dexamethasone, thalidomide) and he achieved >90% reduction of serum monoclonal protein. The attempt of stem cell collection failed and autologous transplantation has not been performed. Currently, one year off therapy he is remaining in very good PR of his MM and in CR of HCL. The possible explanations for the development of these two disorders have been discussed.