Un caso insolito di mieloma a catene leggere

AUTORI

ABSTRACT

An uncommon case of light chain multiple myeloma

A 77-year-old patient with a long-lasting stable proteinuria was admitted to the Nephrology Department for the recent onset of nephrotic syndrome and renal failure. The initial laboratory profile was unremarkable, except for a severe hypogammaglobinemia without monoclonal spike on serum protein electrophoresis. Renal biopsy was performed, showing diffuse amyloidosis; however, immunohistochemistry for light chains was negative, leading to the hypothesis of a genetic amyloidosis. To rule out an AL-type amyloidosis, serum immunofixation and FLC measurement were performed, showing a monoclonal component of lambda light chain with a significant impairment of the kappa/lambda ratio. The bone-marrow biopsy led to the final diagnosis of light chain multiple myeloma. A Bortezomib-based chemotherapy regimen was started, however, despite clinical improvement, lambda free light chains showed a marked increase, leading to a Melphalan-based therapeutic strategy. In conclusion, measurement of FLC ratio was crucial for the diagnosis and the therapeutic monitoring in this troublesome myeloma case.

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