Histopathology of the patient lymph node as compared with a reactive node from an otherwise-healthy node. (A) H&E stain reactive follicle with polarized germinal center and mantle; (D) IHC for MIB-1: the proliferating lymphoid cells within the germinal centers are positive with polarization (dark zone); (G) IHC for BCL-6 (the master regulator of the GC formation): the entire reactive germinal center is positive for BCL-6. (J) IHC stain for PKCδ showing diffusely positive cytoplasmic stain. All the remaining photos are from the lymph node biopsy from our patient: (B) and (C) H&E stains of follicles with varying degree of ill-defined germinal center lacking mantles. (E) and (F) IHC for MIB-1: variable degree of proliferation in different germinal centers is seen with lack of polarization. (H) and (I) IHC for BCL-6: a relative small number of positive cells are present within each germinal center in comparison with the reactive follicle. (K) Absence of PKCδ stain in patient’s lymph node, compared with (J).