We describe a rare case of solitary plasmacytoma (PLC) of the upper jaw and approaches to its differential immunohistochemical diagnosis. This tumor may demonstrate a different histological picture and its diagnosis requires immunohistochemical study with markers CD138, CD38, MUM1, CD79a, CD19, and CD20, which allows differentiating PLC from other lymphoid tumors. Keywords: plasmacytoma, immunohistochemistry, hematology