Isolated testicular involvement in pediatric lymphoma is rare and poses diagnostic challenges. In this study, the case of an isolated testicular B-lymphoblastic lymphoma in a 9-year-old boy is discussed with an emphasis on the difficulties in diagnosing and treating such an unusual presentation. This example illustrates the importance of considering lymphoblastic lymphoma in the differential diagnosis of an unidentified source of testicular enlargement. Furthermore, it highlights the possible efficacy of systemic chemotherapy with or without surgical excision. The article advances our knowledge of this unusual clinical situation.

Primary testicular B-lymphoblastic lymphoma is a rare entity. Primary testicular Ph-positive B lymphoblastic lymphoma was not reported before. We reported a 27-year-old man with primary testicular Ph-positive B lymphoblastic lymphoma, for which fluorescent in-situ hybridization (FISH) for the Philadelphia chromosome was not performed at the initial hospitalization. The patient showed manifestation of Ph-positive acute lymphoblastic leukemia at relapse. In this report, we reviewed the current literature about primary testicular B-lymphoblastic lymphoma, Ph-positive lymphoma and Ph-positive clone evolution. This report has 3 meanings. First: This is first report on primary testicular Ph-positive B lymphoblastic lymphoma. Second: This shows the importance of cytogenics for lymphoma treatment. Third: This implies Philadelphia-positive subclone evolution.