Figure 1.

Kidney biopsy findings. Light microscopy shows large acellular mesangial nodules that are periodic acid−Schiff stain negative and Congo red–positive. In some glomeruli, the large mesangial nodules may involve the glomerulus only segmentally. In addition, in some biopsy specimens, the Congo red stain is only weakly positive. The column on the right pertains to the Congo red stain. The column on the left pertains to hematoxylin and eosin except (a), which is a periodic acid−Schiff stain. Each row represents 1 patient: (a,b) patient 1; (c,d) patient 2; (e,f) patient 3; (g,h) patient 4; and (i,j) patient 5. Original magnification for all ×40, except for (a) and (i) (×20) and d (×10).