Plasmozytome ohne Paraprotein

: Rare plasmocytomas without paraprotein (frequency less than 1%) can present a diagnostic trap. Three observations give grounds for drawing attention to misinterpretation of symptoms and the problematic nature of the diagnosis. In one patient, a monoclonal immunoglobulin (kappa light-chains) was detectable in the bone-marrow myeloma cells (non-excretory plasmacytoma). In a further patient no paraprotein could be found in the myeloma cells (non-secretory plasmacytoma) despite repeated investigations. An additional unusual feature in a third patient was the simultaneous presence of chronic lymphocytic leukaemia; his plasmocytoma was first detected at autopsy.