Evidence for intracellular amyloid formation in myeloma.

Evidence for intracellular formation of amyloid fibrils in a patient with kappa light-chain myeloma is described. Amyloid fibrils were seen as intracytoplasmic inclusions within plasma cells, histiocytes, renal tubule cells, and possibly in hepatocytes. Extracellular amyloid was also present. The electron microscopic studies suggest that amyloid fibrils may form in the Golgi apparatus and within lysosomes.