case_images: PMC10601945_01
case_images: Light microscopic findings. The tissue submitted for light microscopy consisted of superficial medulla without glomeruli. On closer examination, Jones methenamine silver stain revealed the presence of rounded silver-positive inclusions within the cytoplasm of peritubular capillary endothelial cells, tubular epithelial cells, and likely interstitial macrophages (a, b; magnification x200 and x400, respectively). Masson's trichrome stain revealed the presence of cytoplasmic vacuoles in a similar distribution as the silver-positive inclusions (c; magnification x400). An oil red O stain (for lipid), performed on the frozen tissue, showed positivity within likely peritubular capillary and tubular epithelial cells (d; magnification x400).
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case_images: F1
case_images: Jones methenamine silver stain revealed numerous silver-positive cytoplasmic inclusions in tubular epithelial cells, interstitial macrophages, and few peritubular capillary endothelial cells (shown in Fig. 1a, b). Trichrome stain revealed prominent cytoplasmic vacuolization in the same distribution as the silver-positive inclusions (shown in Fig. 1c). O and revealed positive staining within the epithelial cell vacuoles, consistent with lipid accumulation (shown in Fig. 1d). Oil red O is a nonspecific stain for lipid and positive staining is not diagnostic for any particular lipid or lysosomal storage disease.
case_images: The specimen for electron microscopy, stained with methylene blue, revealed a small portion of cortex with severe parenchymal scarring and globally sclerotic glomeruli (a; magnification x40). The only preserved glomerulus in the entire biopsy was identified in this tissue and contained numerous, rounded methylene blue-positive inclusions within the cytoplasm of podocytes (b; magnification x400). Few of the podocyte inclusions appeared to be whorled and lamellated (c; magnification x600).
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case_images: F2
case_images: The only preserved glomerulus in the entire biopsy was identified, which was considerably enlarged but with an otherwise unremarkable glomerular tuft (shown in Fig. 2a). Notably, the podocytes in this intact glomerulus as well as the globally sclerotic glomeruli contained numerous, prominent, rounded, whorled, and lamellated methylene blue-positive cytoplasmic inclusions (shown in Fig. 2b, c).
case_images: Ultrastructural evaluation of the single glomerulus confirmed the presence of numerous atypical lipid inclusions within the podocyte cytoplasm. The electron-dense inclusions were rounded and whorled, sometimes with a characteristic lamellated appearance known as "myelin bodies" (a, c; magnification x4,000 and x12,000, respectively). The inclusions displayed variability in size, ranging from small to quite large (b; magnification x4,000).
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case_images: Ultrastructural analysis confirmed the presence of prominent osmiophilic, concentrically lamellated, whorled inclusions ("myelin" bodies) consistent with glycosphingolipid inclusions in the cytoplasm of podocytes (shown in Fig. 3a-c).
case_images: Ultrastructural evaluation revealed the presence of the atypical lipid inclusions also within the cytoplasm of peritubular capillary endothelial cells (a; magnification x12,000) and arterial myocytes (b; magnification x5,000). Unlike the whorled myelin bodies observed most frequently in the podocytes, these lipid inclusions displayed distinctive layering and lamellations with a stacked configuration at varying angles, known as "zebra bodies" (d; magnification x50,000). The zebra bodies were most frequently observed within larger membrane-bound structures morphologically consistent with lysosomes (c; magnification x20,000).
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case_images: F4
case_images: These ultrastructural inclusions were also present in the cytoplasm of peritubular capillary endothelial cells (shown in Fig. 4a) and vascular smooth muscle cells (shown in Fig. 4b). The cytoplasm of proximal and distal tubular epithelial cells, mesangial cells, and glomerular capillary and peritubular endothelial cells also contained numerous enlarged secondary lysosomes packed with multi-lamellated structures ("zebra" bodies) (shown in Fig. 4c, d), some of which were admixed with vesicular structures with a heterogeneous appearance.