Figure 1136

Light chain amyloidosis on electron microscopy. A, Characteristic fibrillar pattern of amyloid deposits. Long, randomly distributed, nonbranching fibrils with diameters of 8 to 12 nm. B, Amyloid fibrils in the capillary lumen and capillary wall with extension through the glomerular basement membrane (GBM) into the subepithelial space (arrow) fibrils arranged in parallel forming spicules). (Original magnification X48,000, X20,000, respectively.)

thickened, as seen in the PAS-stained sections. In the remaining cases, no renal lesions can be seen on light microscopy. On immunofluorescence, linear staining of basement membranes of glomeruli, tubuli, and vessels can be observed for one of the light chains (k > X). In most cases, the TBMs are more heavily stained than are the glomerular basement membranes (GBMs). Congo red staining is negative for amyloid. On electron microscopy, fine granular electron-dense material can be found in most cases along the endothelial side of the GBM, in the mesan-gium, and along the interstitial side of the TBM. A few cases of heavy chain and of light and heavy chain deposition disease have been described, in most cases with identical morphologic characteristics as described in light chain deposition disease [77,78].

A, Nodular glomerulosclerosis with nodular increase of mesangial matrix. B, Linear staining of the GBM, mesangium, Bowman's capsule, and TBM for the k light chain.

(Continued on next page)

.■ vvt jit-.iij

FIGURE 11-37 (Continued)

C and D, Electron-dense granular deposits in the GBM (C) and around the TBM (D). L—capillary lumen; Pod— podocyte. (Panel A, methenamine silver. Original magnification X400, X400, X 15,000, X6500, respectively.)

■JL

0 0

Post a comment