Clinical and pathological features of testicular diffuse large B-cell lymphoma: a heterogeneous disease.

Most testicular lymphomas are of diffuse large B-cell (DLBCL) type with an outcome inferior to nodal DLBCL. Within an apparently homogeneous group of testicular DLBCLs, small cell components, plasmacytoid differentiation and lymphoepithelial lesions (LELs), features of extranodal marginal zone lymphoma (eMZL), can be identified. The aim of this study was to define the histological features of testicular DLBCL and correlate this with their clinical behavior and outcome. Thirty-six patients with testicular DLBCL (Ann Arbor stage I/II) were identified through the databases of two Dutch regional cancer registries, diagnosed between 1981 and 1999. Follow-up for patients alive was more than 10 years. Medical records and pathology specimens were reviewed. eMZL features were found in 53% of the cases of localized stage testicular DLBCL. Compared to patients with "pure" DLBCL, patients with DLBCL with eMZL features presented more often with stage I disease, normal lactate dehydrogenase, smaller tumors and absence of B-symptoms, and they responded more favorably to initial treatment. Their median survival was 48 months versus 12 months for "pure" DLBCL (p = 0.87). Features of eMZL were commonly identified in testicular DLBCL and they correlated with a more favorable clinical presentation and better response to initial therapy. However, these differences did not reach statistical significance due to small numbers.