Lenalidomide Is Effective for the Treatment of Bortezomib-Resistant Extramedullary Disease in Patients With Multiple Myeloma: Report of 2 Cases

Clinical Practice Points •Extramedullary (EM) disease is a poor prognostic factor of multiple myeloma (MM). Bortezomib has been reported to be the preferred choice of treatment for MM with EM disease. •Some retrospective observations suggest that lenalidomide could be effective in patients with EM disease. •Here we report 2 cases of MM with bortezomib-resistant EM disease that were successfully treated with lenalidomide and dexamethasone. •This study strongly suggests that lenalidomide could be a useful agent for treating bortezomib-resistant EM disease in patients with refractory MM. •Extramedullary (EM) disease is a poor prognostic factor of multiple myeloma (MM). Bortezomib has been reported to be the preferred choice of treatment for MM with EM disease. •Some retrospective observations suggest that lenalidomide could be effective in patients with EM disease. •Here we report 2 cases of MM with bortezomib-resistant EM disease that were successfully treated with lenalidomide and dexamethasone. •This study strongly suggests that lenalidomide could be a useful agent for treating bortezomib-resistant EM disease in patients with refractory MM.