A Case of Extramedullary Progression Despite of Serologic Improvement in a Patient Treated with Thalidomide for Multiple Myeloma

1 Internal Medicine and 2 Laboratory Medicine, Sanggyepaik Hospital, Inje University College of Medicine, Seoul, Korea Thalidomide is an anti-angiogenic agent widely used in patients with multiple myeloma. The response to therapy is commonly monitored using serum and/or urine M protein, as these are known to reflect the tumor burden. Although extramedullary plasmacytomas are tissues with high neovascularization, it has been suggested in some reports that the response to thalidomide in these patients may be inferior, despite changes in the serum M protein level. Herein, we report the case of a patient who newly developed hepatosplenic extramedullary plasmacytoma, despite reduction in the serum M protein level following thalidomide treatment. (Korean J Hematol 2005;40:188-191.)