[Case of AL amyloidosis associated with a remarkable histological progress in a short period].

AL amyloidosis is the most common form of systemic amyloidosis. Although kidney biopsy often is the method by which the disease is identified, small amounts of amyloid in kidney biopsy specimens may be missed on routine examination unless specifically investigated. We present here a previously healthy 60-year-oldmissed on routine examination unless specifically investigated. We present here a previously healthy 60-year-old man who developed nephrotic syndrome. His first renal biopsy showed minimal change nephrotic syndromeman who developed nephrotic syndrome. His first renal biopsy showed minimal change nephrotic syndromesuggesteda subtle depost ommon formsystemicamyloidfibrilhediminationof an early lesion of renal amyloido-s (MCNS). Proteinuria remained refractory to immunosuppressive treatments. Six months later, a repeat renal biopsy clearly showed AL amyloidosis. Re-examination of the first biopsy in the light of the final diagnosis again suggested a subtle deposition of amyloid fibrils. The discrimination of an early lesion of renal amyloidosis with MCNS may often be difficult. It is necessary to maintain a high level of alertness for amyloidosis especially in aged patients with nephrotic syndrome and to consider a repeat biopsy in steroid-resistant cases.