Remission of nephrotic syndrome due to AA amyloidosis and initiation of glomerular repair after surgical resection of localized Castleman's disease.

To shed further light on the eventual destiny of amyloid kidney deposits after interruption of amylogenic stimulus, we report a case of a 47-year-old woman with nephrotic syndrome due to renal amyloidosis, complicating abdominal Castleman's disease. After 5 courses of therapy with melphalan and prednisolone which failed to improve the nephrotic syndrome or her general clinical condition, and 1 year after the diagnosis of renal amyloidosis, surgical excision of the abdominal mass was performed. Whereas her clinical symptoms and other laboratory findings rapidly improved, the proteinuria took 18 months to disappear. A second renal biopsy, performed 30 months after surgical resection, showed persistence of the amyloid deposits in the same extent. However, electron microscopy revealed subtle reparative phenomena at the epithelial site of the basement membrane. We conclude that proteinuria associated with amyloidosis does not only depend on structural damage and that the new synthesized segment of basement membrane observed by us probably represents a mechanism of repair and the start of a long healing process.