Fig. 3

Photomicrographs of the resected breast. Under the microscope, the mass showed the fibrous tissue consisted of medium to large abnormal lymphocytes, which were diffusely distributed. The tumor cells had irregular nuclei and inconspicuous nucleoli (A). Immunohistochemical analysis of the breast showed tumor cells were positive for CD20 (B), CD56 (C), CD3 (D), PAX-5 (E), TIA-1 (F). (G) The ki-67 positive rate was 90%. (H) Tumor cells were also positive for Epstein-Barr virus small-encoded RNA (EBER) by in situ hybridization (A, HE staining with original magnification × 100; B-F, immunohistochemical staining with original magnification × 200; H, in situ hybridization for EBER with original magnification × 200)