CD38 and plasmacytoma: Pathological examination of the mass biopsy indicated extramedullary plasmacytoma (differentiated type); immunohistochemistry revealed CD79a+, CD38+, CD138-, κ+, λ-, CD20-, CD3-, LCA-, CK+, Vimentin+, EMA+, P63-, CD68-, S-100-, P53-, and Ki67 at 50%, and CD34+, ChgA-, Syn-, and NSE-.