PMC9898724_01
Histopathology of an abdominal LN. (A) Diffuse and dense proliferation of atypical large cells with irregular nuclei and prominent nucleoli (haematoxylin and eosin (HE), original magnification x100). (B) High magnification (HE, original magnification x400). (C-K) Immunohistochemical staining showing positivity for CD20 (C), MUM1/IRF4 (G), BCL2 (H), BCL6 (I), MYC (J), and Ki-67 (K), weak positivity for CD5 (E), and negativity for CD3 (D) and CD10 (F).
jslrt-62-268-g001.jpg
PMC9898724_01_jslrt-62-268-g001.jpg
f1
Pathological examination exhibited the diffuse and dense proliferation of atypical large cells with irregular nuclei and prominent nucleoli in the fibrous background (Figure 1A, B). These cells were positive for CD20, MUM1/IRF4, BCL2, BCL6, and MYC, weakly positive for CD5, and negative for CD3 and CD10 by immunohistochemistry (Figure 1C-H, J). They also presented nuclear positivity for BCL6, as generally observed in DLBCL (Figure 1I). The Ki-67 labeling index was approximately 90% (Figure 1K).