RENAL PATHOLOGY LEARNING

Renal Amyloidosis (Part II)

by

Franco Ferrario and Maria Pia Rastaldi

Dr Franco Ferrario
Renal Immunopathology Center
San Carlo Borromeo Hospital
Milan, Italy

Link to Part I

DISTRIBUTION OF AMYLOID DEPOSITS

Amyloid deposition in the kidney can involve not only glomeruli and vessels, but also the interstitium and the tubular basement membranes, giving rise to several different morphological pictures.

There are cases of only minimal glomerular deposition, expressed by small mesangial nodules. Differential diagnosis has to be made from minimal change disease and some cases of IgA GN.

These very early cases need a careful demonstration of the few mesangial amyloid fibrils by electron microscopy.

A more intense mesangial amyloid deposition can be detected. Still to be differentiated from other mesangioproliferative nephritis.

 

In some cases, not only a more evident mesangial deposition, but also an initial involvement of the capillary walls can be detected.

In more advanced cases, huge deposits completely alter the glomerular strucutre.

 

 

When the deposits are massive, a “nodular form” is commonly found and has to be differentiated from other nodular glomerulonephritis, such as diabetic GS, light chain deposition disease and idiopathic MPGN. Amyloid specific stainings have to be performed in order to achieve a correct diagnosis (see part I ).

 

 

The deposition can be limited to the capillary walls. In these cases, a peculiar parallel orientation of amyloid fibrils forms argyrophilic subepithelial spikes. These spikes look like those found in MGN, although bigger and more irregularly distributed.

 

 

Subepithelial spikes due to amyloid deposition can be easily demonstrated by electron microscopy examination: fibrils are perpendicularly oriented and protrude towards the urinary space.

 

 

An almost exclusive arteriolar deposition can be rarely found.

 

 

Amyloid can deposit in the renal interstitium and in the tubular basement membranes. Congo Red staining, with its typical apple-green birefringence, confirms amyloid deposition in these kidney structures.

 

 

A massive deposition of amyloid can be detected in arteries and arterioles.

 

 

 

Questions

 

Read all the Renal Pathology publications

REFERENCES
1. Gertz MA, Lacy MQ, Dispenzieri A, Hayman SR. Amyloidosis. Best Pract Res Clin Haematol 2005; 709-27. Review.
2.

Sezer O, Eucker J, Jakob C, Possinger K. Diagnosis and treatment of AL amyloidosis. Clin Nephrol 2000; Jun 53(6): 417-23. Review.

3.

Gertz MA, Rajkumar SV. Primary systemic amyloidosis. Curr Treat Options Oncol. 2002 Jun 3(3): 261-71. Review.

4.

Comenzo RL. Primary systemic amyloidosis. Curr Treat Options Oncol. 2000 Apr 1(1): 83-9. Review.

5.

Pozzi C, Locatelli F. Kidney and liver involvement in monoclonal light chain disorders. Semin Nephrol 2002 Jul 22(4): 319-30. Review.

6.

Gertz MA, Lacy MQ, Dispenzieri A. Immunoglobulin light chain amyloidosis and the kidney. Kidney Int. 2002 Jan; 61(1): 1-9. Review.

7.

Gertz MA, Lacy MQ, Dispenzieri A. Amyloidosis: recognition, confirmation, prognosis, and therapy. Mayo Clin Proc. 1999 May; 74(5): 490-4.

8. Kyle RA, Bayrd ED. Amyloidosis: review of 236 cases. Medicine (Baltimore). 1975 Jul; 54(4): 271-99.