Representative images showing immunohistochemical expression in patients with UCD and iMCD. (A-H) UCD case with B-cell–rich germinal centers and increased CD5⁺/CD19⁺ B cells, whereas CD3⁺ small T cells are relatively sparse. (I-P) iMCD case with dense T cells in the interfollicular regions and decreased CD20/PAX-5 B cells and CD5⁺/CD19⁺ B cells. Few polyclonal CD138⁺ PCs are present around the nodules in both UCD and iMCD. Original magnification ×100 for panels A-D,I-L and ×200 for panels E-H,M-P.