Extramedullary plasmocytoma associated with a massive deposit of amyloid in the duodenum

Figure 1 CT showing a mass on the fourth part of the duodenum (arrow).

Figure 2 Gross appearance of the surgical specimen containing the tumor (arrow).

Figure 3 Histopathological examination displaying a dense and diffuse infiltrate of plasma cells and amyloid deposit (arrow). (HE × 400).

Figure 4 Immunohistochemical findings (positive cells in brown, × 400). A: Most plasmocytoid cells were positive for κ light chain; B: Few plasmacytoid cells showing λ light chain staining; Plasmocytoid cells were positive for CD56 (C) and negative for CD20 (D).