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

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.