Diffuse large B-cell lymphoma of the testis in a 69 y/o male. The patient presented with diffusely enlarged right testis. Serum tumor markers (beta-hCG, AFP, and LDH) were within reference range. Orchiectomy specimen showed complete replacement of testicular parenchyma by fleshy, yellow-tan mass. The sections show a diffuse interstitial infiltrate of large, atypical lymphoid cells displacing the seminiferous tubules. The cells have round or oval vesicular nuclei, inconspicuous nucleoli and scant cytoplasm. On immunohistochemistry, the tumor cells were positive for CD20, BCL2 and MUM1 and focally positive for BCL6. They were negative for CD3, CD5, CD10, cyclinD1, CD30, TdT, CD34, and EBER. They were negative for t(14;18) translocation, C-MYC rearrangement and BCL6 rearrangement.