Morphological and immunophenotypic features of nodal t(14;18)-positive and t(14;18)-negative FLs. (A) t(14;18)-positive FL showing a nodular growth pattern, with follicles growing back to back and the lack of a defined mantle zone, (original magnification ×50; hematoxylin and eosin [H&E] stain). (B) Higher magnification demonstrates the presence of predominantly centrocytes with few intermingled centroblasts in the follicles characteristic of FL grade 1/2, (original magnification ×400; H&E stain). (C-D) BCL2-R–neg CD23⁺ FCL with diffuse growth pattern. (C) The H&E stain shows an inguinal lymph node with partial involvement of a diffuse lymphoid infiltration that leaves a rim of normal lymph node in the periphery. (D) The tumor cells are strongly CD23⁺. Note that in the periphery of the lymph node there are residual normal GCs and the CD23 stain highlights the follicular dendritic cells. (E) The tumor cells are also strongly positive for CD10. The residual normal GCs are CD10⁺. (Snapshot of scanned slides, ×10). (F-G) BCL2-R–neg CD23⁺ FCL with follicular growth pattern. (F) The H&E stain shows an axillary lymph node with involvement of a lymphoid proliferation with follicular growth pattern (original magnification ×40; H&E stain). (G) The tumor cells are CD23⁺ (original magnification ×40; immunohistochemistry). (H) The tumor cells are BCL2⁻. Note that the B cells in the attenuated mantle zone are BCL2⁺. (original magnification ×400; immunohistochemistry). (I) The neoplastic cells in the follicles are CD23⁺, (original magnification ×400; immunohistochemistry).