Plasma cell dyscrasias, including multiple myeloma, are characterised by the expansion of immunoglobulin-secreting B cells. Extracellular immunoglobulin accumulation occurs uncommonly. We describe a case multiple myeloma with extensive deposition of extracellular crystals, identified on the bone marrow trephine biopsy on two separate occasions and also in the bone marrow aspirate. The significance of identifying such crystals is in appreciating their association with clonal plasma cell proliferations.
- Multiple myeloma