Successful treatment of extramedullary tumors with low-dose thalidomide in patients with multiple myeloma.

Extramedullary tumor (EMT) is a poor prognostic factor of multiple myeloma (MM). The majority of patients report poor efficacy of thalidomide in MM with EMT, and bortezomib is the preferred choice of treatment. We report two cases of MM with EMTs in which thalidomide was highly beneficial. Case 1 has been in remission for ten months with 100 mg every other day of thalidomide monotherapy, which is the lowest dose to be reported in a successfully treated case of MM with EMT. Case 2 eventually became refractory, but low dose thalidomide gave excellent disease control over a period of eleven weeks, despite the EMT being in a highly aggravated state. Some reports have speculated that EMT cases with preceding bone marrow transplantation (BMT) are an exception and have a good response to thalidomide, but the present two cases have no history of BMT. In conclusion, low dose thalidomide can be effective in MM with EMT and should be considered as a treatment option, especially in the elderly.