B-cell lymphomas.

(A) DLBCL-centroblastic. A uniform population of large centroblasts with nuclear membrane-associated nucleoli has completely replaced normal splenic structure (H&E, × 750). (B) DLBCL-immunoblastic. A pleomorphic population of immunoblasts with large nucleoli as well as some centroblasts (H&E, × 750). (C) DLBCL-histiocyte associated. A pleomorphic population of large lymphoid cells with prominent area of histiocytic cells (lower left) (H&E, × 1000). (D) DLBCL-primary mediastinal (thymic). Tumor arising in the thymus composed of a mixed population of B220⁺ cells (inset; H&E, × 15) including immunoblasts (H&E, × 750). (E) Classic Burkitt lymphoma. Large cells with prominent nucleoli central or in peripheral areas of the nucleus. Apoptosis is a striking feature (H&E, × 1000). (F) Burkittlike lymphoma. Medium-sized cells with central nucleoli or stipple chromatin with moderate apoptosis (H&E, × 750).