Histologic features of t(14;18)⁻FL. (A-F) Case FL7, group B2. (A) Axillary LN with effaced architecture by an atypical lymphoid infiltration with follicular growth pattern. The follicles are back to back without well-defined mantle zones (hematoxylin and eosin [H&E]; original magnification, ×50). (B) The follicles are BCL2⁻ with the 100/D5 clone (immunoperoxidase; original magnification, ×50). (C) The follicles are CD20⁺. (D) The tumor cells are CD23⁺. (E) MIB1 stain demonstrates low proliferation within the follicles without polarization. (F) The tumor cells are also negative with the alternative BCL2 antibody clone E17 (C-F; immunoperoxidase; original magnification, ×100). (G-M) Case FL11, group A1. (G) Inguinal LN with atypical lymphoid proliferation with follicular (right side) and diffuse (left side) growth pattern (H&E; original magnification, ×25). (H-I) The cells are negative with the BCL2 100/D5 clone and the E17 clone. (J-K) The tumor cells are CD10⁺ in the follicular and diffuse areas. (L-M) CD23 is strongly expressed in the follicular and diffuse areas (H-M; immunoperoxidase; original magnification, ×100).