BCL2⁻ FL with an in situ FLIS component. (A-B) The LN exhibits a proliferation of large follicles lacking polarization, highlighted by the CD20 stain (B). (C-D) A CD10 stain (C) demonstrates more intense staining of the FLIS component than the FL component, and the BCL2 stain (D) highlights the intensely staining FLIS component, whereas the FL is BCL2⁻. (E-F) A MIB-1 stain (E) identifies a low proliferation rate within the abnormal follicle, and a CD3 stain (F) reveals admixed T cells. Original magnification ×40. Case 29 in Table 3.