Primary testicular diffuse large B-cell lymphoma with gonadal vein tumor thrombus: A case report and review of the literature.

Abstract

Background: Primary testicular lymphoma (PTL) is a rare, aggressive malignancy, representing a small fraction of testicular tumors and non-Hodgkin lymphomas, yet it is the most common testicular malignancy in older men. Diffuse large B-cell lymphoma (DLBCL), which is typically the aggressive subtype, dominates PTL and shows diffuse B-cell infiltration. Venous tumor thrombus, uncommon in lymphomas, is uniquely reported in this case of testicular DLBCL with gonadal vein involvement.

Case summary: A 62-year-old man presented with a two-month history of painless left testicular swelling and stiffness. Diagnostic imaging [ultrasonography, computed tomography (CT), and ¹⁸F-fluorodeoxyglucose positron emission tomography/CT (¹⁸F-FDG-PET/CT)] revealed bilateral testicular masses and a gonadal vein tumor thrombus (SUVmax 16.5). Left orchiectomy confirmed DLBCL with CD20, Bcl-2, and MUM1 positivity (Ki-67: approximately 80%). The disease was staged as Ann Arbor stage IVA (International Prognostic Index score 3, high-intermediate risk). The patient received Rituximab, Polatuzumab Vedotin, Cyclophosphamide, Epirubicin, and Prednisolone chemotherapy, completing the first cycle with good tolerability. No adverse events were reported, and follow-up is ongoing to assess long-term outcomes. This case highlights the diagnostic utility of ¹⁸F-FDG-PET/CT and the importance of multidisciplinary management in rare PTL presentations with tumor thrombus.

Conclusion: This case demonstrates the diagnostic complexities of PTL with gonadal vein tumor thrombus, underscoring the importance of considering lymphoma in elderly patients with testicular masses and venous involvement. A multi-disciplinary team including urologists, hematologists, and radiation oncologists is needed to ensure appropriate therapy.