A 74-year-old man presented with bilateral testicular masses and back pain. A positron emission tomography scan showed increased metabolic activity in bilateral testes (panel A; ROI, region of interest; SUV, standardized uptake value), and lytic lesions in the left pubic symphysis and L5 vertebral body (panel B). Bilateral orchidectomy and L5 vertebral specimens were characterized by sheets of medium-sized blastic cells (panel D; original magnification ×400, hematoxylin and eosin stain) positive for PAX5 (panel E; original magnification ×400), terminal deoxynucleotidyltransferase (panel F; original magnification ×400), CD10, and CD34 by immunohistochemistry. Fluorescence in situ hybridization (FISH) analyses performed on both testicular and L5 vertebral specimens revealed BCR-ABL1 rearrangement (panel D, insert). Bone marrow was negative for acute leukemia by morphology and flow cytometry. Results of chromosomal and FISH analyses for BCR-ABL1 were negative. Reverse transcription polymerase chain reaction (RT-PCR) analysis revealed 0.48% of e1a2 BCR-ABL1 fusion transcript. The patient was diagnosed with Philadelphia chromosome–positive B-lymphoblastic lymphoma (B-LBL), treated with hyper–cyclophosphamide, vincristine, doxorubicin plus dasatinib and achieved complete remission.Four years later, the patient presented with a right kidney mass (panel C, arrow). A biopsy revealed recurrent B-LBL. Again, bone marrow analysis was negative for acute leukemia by morphology and flow cytometry and was negative for BCR-ABL1 by RT-PCR. The patient died 1 week later. This is the first case of Philadelphia chromosome–positive B-LBL involving the genitourinary system and bone as isolated tissue masses at both initial presentation and relapse.