PMC6354159_01
(a) Diffuse infiltration of the dermis by large lymphoid tumor cells with variable proportions of centroblasts and immunoblast-like cells (Hematoxylin-Eosin: magnification X400), (b-e) Positive immunostaining of large tumor cells for CD20, CD5, MUM1, and Bcl2, respectively (magnification X200) and (f) Ki67 immunostaining in approximately 90% of large tumor cells.
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fig1
Histological examination demonstrated a diffuse dermal infiltration by large lymphoid cells (Figure 1(a)). MUM1/IRF4, Bcl6, Bcl2, and cytoplasmic IgM/lambda whereas CD3, CD56, CD23, CD21, CD10, CD30, cyclin D1, CD68, lysozyme, myeloperoxidase, and CD34 were not detected (Figures 1(b)-1(e)). MYC immunopositivity was observed in 20% of tumor cells but our case was considered as MYC negative since the threshold for MYC immunohistochemical positivity in DLBCL is immunostaining of >40% of tumor cells. Ki-67 immunostaining was detected in approximately 90% of large tumor cells (Figure 1(f)).