Successful treatment of isolated central nervous system recurrence of primary testicular lymphoma by autologous stem cell transplantation using a conditioning regimen of thiotepa and busulfan.

Primary testicular lymphoma (PTL) frequently relapses in the central nervous system (CNS) despite prophylactic intrathecal chemotherapy, and the outcome for CNS recurrence of PTL is very poor. We report a case of isolated CNS recurrence of bilateral PTL. Our patient achieved complete response (CR) after rituximab-combination chemotherapy for PTL. Approximately five years later, isolated CNS recurrence of PTL occurred. Our patient achieved CR again after high-dose methotrexate therapy and autologous stem cell transplantation (ASCT) with a conditioning regimen of thiotepa and busulfan as a consolidation therapy. The secondary failure of platelet recovery, probably caused by busulfan, occurred after the platelet engraftment. Our patient has remained in CR for over three years. The treatment strategy for CNS recurrence of PTL is mainly whole-brain radiotherapy or high-dose methotrexate-based chemotherapy; however, CNS recurrence of PTL may occur again even after achieving CR. ASCT with a conditioning regimen of thiotepa and busulfan is the optimal consolidation therapy for secondary CNS lymphoma. To the best of our knowledge, this is the second reported case of a patient with isolated CNS recurrence of PTL successfully treated by ASCT with a conditioning regimen of thiotepa and busulfan as a consolidation therapy.