Extramedullary plasmacytoma (EMP) is an uncommon plasma cell neoplasm results from plasma cell proliferation and consists of monoclonal plasmacytic infiltration, without bone marrow involvement and any other systemic characteristics of multiple myeloma. EMP accounts for 3% of all plasma cell neoplasms and approximately 80% to 90% of EMP involve submucosa of the upper aerodigestive, while scrotal, dermis and retroperitoneal infiltration are very rare. There are no consensus guidelines for treatment, but EMP is highly radiosensitive, surgery may be considered for some sites, but 11 at 30% can progress in multiple myeloma. We report here an exceptional case of recurrent EMP in much localization. It's about a man 72 years old with initially testicular plasmocytoma who generalized the plasmacytic infiltration after 16 months in skin and progressively in mediastinal and retroperitoneal plasmacytoma, without any medullar and bone involvement.