Diffuse large B-cell lymphoma: clinical and biological characterization and outcome according to the nodal or extranodal primary origin.

Objective: To study the main clinicobiologic features, response, and outcome of patients with diffuse large B-cell lymphoma (DLBCL) according to the primary site, lymph node, or different extranodal organs of the disease.

Methods: We included 382 patients consecutively diagnosed with DLBCL in a single institution during a 13-year period. Morphology, immunophenotyping, proliferation index, differentiation profile, bcl-2/JH rearrangement, and clinical characteristics were analyzed according to the primary site of the lymphoma.

Results: Sites of the disease were: lymph node, 222 cases (58%); Waldeyer's ring (WR), 42 (11%); and extranodal sites, 118 (31%), including GI tract in 45 cases. Primary extranodal cases, particularly GI, showed a bcl-6 expression more frequently than nodal cases. Patients with primary WR or GI lymphomas presented with early-stage disease, no marrow infiltration, normal serum lactate dehydrogenase, and low- to low/intermediate-risk international prognostic index (IPI) more frequently than the remainder. Complete response (CR) rate was 63%, with WR and GI lymphomas having a higher CR rate (85% and 80%, respectively) than the other groups. In the whole series, 5-year overall survival (OS) was 52%. Patients with WR or GI lymphomas showed better OS (5-year OS: 77% and 68%, respectively) than patients with nodal or other extranodal sites. In the multivariate analysis, IPI, bulky disease, and beta2-microglobulin were the main variables to predict OS; no nodal or extranodal site maintained their prognostic value.

Conclusions: In the present series, the primary site of disease was associated with particular clinicopathologic features and outcome, though the latter largely depended on other factors.