Isolated testicular relapse after bone marrow transplant with total body irradiation and testicular boost in acute lymphoblastic leukemia.

A 7-year-old boy with Ph+ ALL received an allogeneic BMT in second remission. Conditioning included cyclophosphamide 60 mg/kg for 2 days, TBI 2 Gy twice daily for 3 days (12 Gy) and a single testicular boost of 4 Gy. He remained in hematological remission after BMT but developed isolated testicular relapse at 17 months. He underwent orchiectomy of the affected testis, 24 Gy testicular radiotherapy and systemic chemotherapy. He remains in remission 24 months after the testicular relapse. This is the first report of isolated testicular relapse which received a testicular irradiation boost included in the conditioning.