RESUMEN
<p><b>OBJECTIVE</b>To study the clinicopathologic features, immunohistochemical findings and prognosis of primary diffuse large B-cell lymphoma (DLBCL) of testis.</p><p><b>METHODS</b>Fourteen cases of primary DLBCL of testis, diagnosed according to the 2001 World Health Organization staging standards for hematopoietic and lymphoid tumors, were retrospectively studied. Immunohistochemical study was performed and follow-up information analyzed.</p><p><b>RESULTS</b>The median age of the patients was 62 years. There were 10 patients in stage I, 3 in stage II and 1 in stage IV. Follow-up information was available in 11 patients (78.6%). Three of which were still alive and eight died (with duration of survival ranging from 5 to 19 months). The patients usually presented with unilateral painless enlargement of testis. Histologically, the lymphoma cells of all cases showed a centroblastic appearance. One case belonged to the germinal center B cell-like subtype on immunohistochemical study, while the remaining 13 cases were classified as non-germinal center B cell-like subtype. Ten of the 14 cases (71.4%) showed overexpression of p53 protein. Most cases demonstrated high proliferation index. Six of the 14 cases (42.9%) were positive for bcl-2 protein. The overall 1-year, 2-year and 5-year survival rates were 45.5%, 17.0% and 17.0%, respectively.</p><p><b>CONCLUSIONS</b>Most cases with primary DLBCL of testis were of peripheral activated B-cell origin. The prognosis is usually not favorable, with propensity of local relapse and systemic dissemination. Accurate pathologic diagnosis relies on detailed histologic examination and immunohistochemical study.</p>