Figure 4.

Representative cases of reactive and neoplastic CD56⁺ plasmacytoid dendritic cells. Gray: CD56^– reactive plasmacytoid dendritic cells (PDC); blue: CD56⁺ reactive PDC; red: CD56⁺ neoplastic PDC. (A) CD56⁺ reactive PDC are consistently positive for CD2 and CD303, negative for CD7. CD38 expression is bright. (B) In contrast, neoplastic CD56⁺ neoplastic PDC are often negative for CD2 with decreased to negative CD303 expression. CD7 expression is often positive and CD38 expression level is often decreased. Focusing on CD56^– PDC (gray) in both panels (A) and (B), these cells are positive for CD303 and CD38. CD2 shows a bimodal pattern of expression (both negative and positive cells present). A small subset of reactive PDC is CD7⁺ and these CD7⁺ reactive PDC are negative for CD56.