Light chain deposition nephropathy in necropsy material

The clinical and necropsy findings on 7 patients with monoclonal immunoglobulin light chain deposition nephropathy are described (4 cases with a myelomatous and 3 with a non-myelomatous background). All patients had moderate proteinuria and progressive azotemia. Three myelomatous and all three non-myelomatous patients died from uremia after a mean time of 12 and 23 months, respectively, from the first presentation. Immunohistochemically, 6 patients had kappa, and one had lambda light chain deposition. Light microscopically, interstitial fibrosis, tubular atrophy and arteriolar hyalinosis were present in all cases. The glomeruli showed no changes (1 case), or displayed patterns of mesangial widening: mild (1 case), nodular (mesangial nodules, 4 cases) or global lobular expansion (1 case). Mesangial nodules were observed either with or without lamellation. Around the nodules, microaneurysms were seen in 2 cases. Mesangial nodular expansion was accompanied by crescents in 56% of the glomeruli in a male patient suffering from kappa light chain deposition nephropathy without myeloma. The present findings and a review of the literature indicate the following mesangial changes in light chain deposition nephropathy: 1. no changes, 2. mild expansion, 3. nodular expansion with and without lamellation, and 4. lobular expansion. Subtypes 2, 3 and 4 may be present in parallel, may occur with or without cellular proliferation, and may be accompanied by crescents. The term nodular glomerulosclerosis to describe mesangial nodular expansion is not completely correct, and hence its use is not recommended.