Extramedullary Plasmacytoma Mimicking Pancreatic Cancer:An Unusual Presentation

Multiple myeloma is a plasma cell tumor that homes to and expands in the bone marrow and that, despite the new availabledrugs, remains incurable. Extramedullary plasmacytoma is a not frequent manifestation during the natural history of multiplemyeloma and is frequently associated with plasma cell bone marrow infiltration. The most common locations for an EMP includethe gastrointestinal tract, pleura, testis, skin, peritoneum, liver, endocrine glands, and lymph nodes. Primary involvement of thegallbladder fossa is exceedingly rare. In this report, we describe a patient with multiple myeloma who achieved a clinical andserological remission after autologous transplant but progressed rapidly at extramedullary site mimicking a second cancer (i.e.,pancreatic or biliary cancer). In this case, the extramedullary localization was refractory to standard therapy, differently from bonemarrow localization, but responded to lymphoma-like therapy. In this patient (i) the particular site of developing plasmacytoma isthe gallbladder fossa, (ii) the timing of onset of this neoplasm is immediately after autologous transplant, and (iii) its disjunctionfrom primary myeloma is that it appears in clinical and serological remission phase which may be confounding during thediagnostic approach simulating a different tumor (solid tumor).