Clinical, Pathological and Immunohistochemical Characteristics of Patients with Primary Testicular Lymphoma Undergoing Orchiectomy: A Systematic Review and Meta-Analysis.

Background: Primary testicular lymphoma (PTL) is a rare and aggressive malignant tumour with no specific clinical symptoms. Large-scale evidence-based medical evidence to guide preoperative diagnosis is lacking at present. This study aimed to analyse the clinical, pathological and immunohistochemical characteristics of patients with PTL undergoing testicular resection surgery.

Methods: Literature on the clinical characteristics of patients with PTL undergoing orchiectomy was retrieved from databases, including PubMed, Web of Science, Embase, Cochrane Library, China National Knowledge Infrastructure (CNKI) and Wanfang Data. The search covered all available records from the inception of these databases until December 31, 2023. Data extraction was followed by a meta-analysis using Stata 15.0 software.

Results: A total of 22 articles and 475 cases of PTL were included. The meta-analysis revealed that 58.1% of patients with PTL undergoing orchiectomy were under 60 years old, and 41.9% were 60 years or older. The lesion is mostly located on the right side (55.1%). Common symptoms included testicular swelling and falling swelling (91.3%), hydrocele testis (31.0%) and testicular pain (23.0%). Ann Arbor stages I-IV accounted for 53.3%, 16.7%, 14.8% and 15.7%, respectively. Diffuse large B-cell lymphoma (DLBCL) cases were higher at 95.5% than NK/T-cell lymphoma cases at 8.2%. Amongst DLBCL cases, 69.3% were non-germinal centre B-cell (GCB) subtype, and 27.6% were GCB subtype. Immunohistochemistry markers showed 95.9% CD₃ negative, 94.9% CD₁₀ negative, 94.4% CD₂₀ positive, 88.4% multiple myeloma oncogene-1 (MUM-1) negative, 73.6% B-cell lymphoma-6 (BCL-6) negative and 66.5% BCL-2 positive. Laboratory findings indicated that 70.4% of patients had a tumour proliferating cell nuclear antigen (Ki67) index of ≥80%, 36.0% had increased serum lactate dehydrogenase level and 22.9% had increased serum β2-microglobulin level.

Conclusions: PTL is rare, and it often occurs in elderly male patients. Common symptoms include testicular swelling and falling swelling, and the common histological type is DLBCL. Diagnosis should be based on histopathological characteristics and immunohistochemical examination.