Diffuse Large B-cell Lymphoma of the Testis: This adult male (>50 yrs) presented with testicular discomfort and was found (on ultrasound) to have a hypoechoic and hypervascular, ill-defined area in the periphery of the testis. Serum tumor markers (AFP, beta-hCG, LDH) were within reference range. The orchiectomy specimen shows a 2.0 cm solid nodule in the location corresponding to the ultrasound findings. The yellow-white, worm-like structure in the lower pole is epididymis filled with spermatozoa. Sections showed a diffuse proliferation of large atypical lymphoid cells with vesicular nuclei and prominent nucleoli. The immunohistochemical profile of the tumor cells was as follows: POSITIVE - pan B-cell markers (CD20, CD79a), CD10, MUM-1, BCL6. NEGATIVE - CD3 (positive in background T-cells), BCL2, CD30. Ki-67 labeling index was 80%.