[Thoracic and retroperitoneal dissemination of multiple myeloma. 2 cases].

The dissemination of multiple myeloma out of the bone marrow is very rare, even though the observation of plasmacytosis in the bodies of patients having died of this disease is not rare. We present 2 patients affected by multiple myeloma and with extra-bone marrow plasmacytomas at the diagnosis, localized at posterior mediastinum and retroperitoneum, discovered by tomography.