Crystal storing histiocytosis: a rare presentation of plasma cell myeloma.

Crystal storing histiocytosis (CSH) is a very rare association with plasma cell dyscrasias. It is presumed to be an intra-lysosomal accumulation of the secreted paraprotein aggregated into crystals and is associated with presence of variable numbers of histiocyte-like cells with phagocytosed crystalline inclusions in the bone marrow and other extramedullary sites Herein we report a case of multiple myeloma associated with CSH with a rapidly downhill clinical course. There was diagnostic confusion at the outset with a histiocytic disorder which was clarified with the use of Immunohistiochemistry along with serum protein electrophoresis and immunofixation.