Multiple myeloma (MM) is typical of uncontrolled and clonal growth of malignant plasma cells in the bone marrow, then leads to primary symptoms related to bone narrow infiltration and destruction bone lesion. The term of extramedullary plasmacytoma is used to defined malignant plasma cells are found out of the bone marrow. In this study, we reported a rare duodenum plasmacytoma accompanied by gastrointestinal symptoms.