New provisional B-cell lymphoma entities. (A-D) LBCL with IRF4 rearrangement. (A) Note the very large abnormal-appearing follicles in the central portion of this tonsil. (B) The neoplastic follicles have numerous transformed cells that are (C) IRF4/MUM-1⁺ and (D) BCL6⁺. (E-H) Burkitt-like lymphoma with 11q aberration. (E) The touch imprint demonstrates a monotonous population of transformed cells with basophilic cytoplasm that are (F) CD20⁺, (G) have a very high MIB1/Ki-67 proliferation fraction, and are (H) BCL6⁺. (A-B) Hematoxylin and eosin stain; (C,D-H) immunoperoxidase stains as specified; (E) Romanowsky-type stain.