A 56-year-old white man presented with fatigue and serum creatinine of 4.9 mg/dL. His se-rum creatinine was 0.9 mg/dL 4 years previously, and 1.6 mg/dL 2.5 years previously. Overthe next month, creatinine increased further to 6.1 mg/dL, associated with 1� protein, and

bland urinalysis. Twenty-hour urine protein was 0.6 g/L, and hematocrit was 29%.

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Case provided by Agnes B. Fogo, MD,Department of Pathology, Vanderbilt Univer-sity Medical Center, Nashville, Tennessee.

© 2002 by the National Kidney Foundation, Inc.doi:10.1053/ajkd.2002.34104

If you have an interesting case you wouldlike to submit for consideration, please contacttheAJKDEditorial Office.

Figure 5A. What lesion do you observe on lowpower? (PAS, � 100).

Figure 5B. What diagnostic lesion do you observeon higher power? (PAS, � 400).

Figure 5C. What additional tests should you perform on the renal biopsy?

AJKD QUIZ PAGEJUNE 2002

American Journal of Kidney Diseases, Vol 39, No 6 (June), 2002: p xliixlii

A 56-year-old white man presented with fatigue and serum creatinine of 4.9 mg/dL. His se-rum creatinine was 0.9 mg/dL 4 years previously, and 1.6 mg/dL 2.5 years previously. Overthe next month, creatinine increased further to 6.1 mg/dL, associated with 1� protein, and

bland urinalysis. Twenty-hour urine protein was 0.6 g/L, and hematocrit was 29%.

Figure 5A. What lesion do you observe on low power? (PAS, �100).

There is a chronic interstitial nephritis with tubulointerstitial fibrosisand scattered lymphoplasmacytic infiltrate. Even on low power, hard,fractured casts with surrounding cell reaction may be seen withintubules. Glomeruli appear unremarkable with only mild mesangialexpansion.

Figure 5B. What diagnostic lesion do you observe on higher power? (PAS, �400).

On higher power, there are diagnostic casts with syncytial cell reaction surrounding the hard,fractured-appearing material, diagnostic of light chain cast nephropathy.

AJKD QUIZ PAGE ANSWERSJUNE 2002

Answer: Light Chain Cast Nephropathy With Light ChainDeposition Disease

Case provided by Agnes B. Fogo, MD,Department of Pathology, Vanderbilt Univer-sity Medical Center, Nashville, Tennessee.

If you have an interesting case you wouldlike to submit for consideration, please contacttheAJKDEditorial Office.

Figure 5C. What additional tests should you perform on the renal biopsy?

Additional tests that should be performed on the renal biopsy include immunofluorescence and electronmicroscopic studies to rule out other processes related to light chain deposition. These studies revealed tracediffuse glomerular basement membrane and 1 to 2� tubular basement membrane staining with � light chain,with no � or immunoglobulin staining. (Anti-� light chain antibody immunofluorescence,�200).

Figure 5D. Electron microscopy confirmed amorphous, granular deposits along the endothelial aspect of theglomerular basement membrane (transmission electron microscopy, �8,000) and along the outer aspects of tubularbasement membranes (not shown). It is important to recognize that patients with a monoclonal protein maymanifest more than one lesion consequent to the abnormal protein. The combination of light chain cast nephropa-thy and light chain deposition disease is the most common of the possible combined lesions. Light chaindeposition disease typically manifests as a nodular glomerulosclerosis by light microscopy. Earlier, more subtle

lesions can be recognized by immunofluoresence and electron microscopy, as in this case.

AJKD QUIZ PAGE ANSWERS(continued)