An upsurge of the serum free light chains as a possible missing link in tumour lysis syndrome in multiple myeloma.

Multiple myeloma (MM) is a slow-growing malignancy characterized by a low proliferation rate of plasma cells and a relatively rare incidence of tumour lysis syndrome (TLS). Three myeloma patients developed TLS following cytotoxic therapy (two after radiation treatment) that was associated with an abrupt increase of serum free light chains (FLC). All three patients demonstrated extramedullary plasmacytomas that exhibited aggressive features compared to the original myeloma. The findings suggested that an abrupt liberation (rather than slow secretion) of FLC from myeloma cells may trigger a fulminant cast nephropathy and present an unrecognized risk factor and potentially aggravating component of TLS.