Unusually aggressive primary testicular diffuse large B-cell lymphoma initially presenting as systemic disseminating metastases in older adult men: a case report.

Primary testicular lymphoma (PTL) accounts for 1-2% of all nonHodgkin lymphomas (NHL), 4% of extranodal nonHodgkin lymphomas, and ~9% of testicular malignancies. A rare subtype of PTL is primary testicular diffuse large B-cell lymphoma (PT-DLBCL), which may initially present as disseminating metastasis in older adult males and has a poor prognosis. Case presentation: Herein, the authors describe the case of a 64-year-old man with the chief complaint of a painless unilateral scrotal mass. Computed tomography scans of the abdomen and a pelvic examination demonstrated a left testicular tumor with multiple lymphadenopathies partially aggregated in the para-aortic area and disseminated to multiple soft tissues and organs. Subsequently, the patient underwent a left radical orchiectomy. Pathological and immunohistochemical examinations confirmed the diagnosis of left PT-DLBCL with systemic disseminating metastases. Clinical discussion: PTL often aggressively spreads to other extranodal organs, such as the contralateral testis, central nervous system, lung, pleura, Waldeyer's ring, and soft tissues. In men over 60 years of age, PT-DLBCL is the most common testicular malignancy. However, extensive systemic metastasis as the initial presentation is extremely rare. PT-DLBCL has a dismal prognosis and requires radical orchiectomy followed by multimodal therapy and central nervous system prophylaxis or systemic intervention to improve survival. Conclusion: The diagnosis of PT-DLBCL through preoperative and imaging examinations is often challenging. Thus, histopathology and immunohistochemical markers play a crucial and valuable role in the definite diagnosis and differential diagnosis of PTLs.