The Renal Distribution of Iron (Fe) in Primary Hemochromatosis: An Autopsy Study.
Vijayalakshmi Ananthanarayanan, Shane Meehan, Anthony Chang. University of Chicago, IL
Background: The distribution of iron (Fe) within the renal parenchyma of patients with primary hemochromatosis has not been studied. We conducted this study to determine the spectrum of Fe distribution in autopsy kidneys in the setting of primary hemochromatosis. We also evaluated whether the presence of the H63D or C282Y mutations, the most common mutations in hereditary hemochromatosis, resulted in a difference in iron distribution in the kidneys of affected patients.
Design: We identified 12 cases of hemochromatosis in our pathology database from 1993-2010, after excluding cases of hemosiderosis and secondary hemochromatosis. H&E and Prussian blue stain were analyzed and the distribution of Fe in the various compartments of the renal parenchyma was assessed. These findings were correlated with the available clinical and mutation data (H63D and C282Y).
Results: Of the 12 cases of primary hemochromatosis, there were 8 males and 4 females with an average age of 54 years (range: 32 to 73 years). Eight patients had histologically proven cirrhosis while 4 patients had increased Fe deposition in the hepatocytes. In the kidneys, there typically was more staining for Fe in the cortex than the medulla. Within the cortex, Fe was noted in the glomeruli, proximal convoluted tubules (PCT) and distal nephron segments. In most cases, the staining in the distal nephron segments, when present, was more intense than the PCT. Podocytes and parietal epithelial cells were the primary cells in glomeruli with Fe, but no mesangial or glomerular endothelial staining was identified. One case showed the presence of Fe in only glomeruli limited to the podocytes. Few cases had additional rare interstitial and endothelial staining. Furthermore, patchy staining of the glomerular basement membranes in globally sclerotic glomeruli, Bowman's capsules and tubular basement membranes was also noted in a subset of cases. In the four cases where mutation data was available, no difference in Fe distribution was observed.
Conclusions: This is the first study to describe the distribution of Fe in autopsy kidneys of primary hemochromatosis patients. Most cases showed a predominant staining pattern in the cortex with a greater distribution in the distal nephron segments. Regardless, of the involved compartment, Fe deposition was patchy and irregular. The persistence of iron deposition in the podocytes could be due to their terminal differentiation, but this would require further study.
Category: Kidney (does not include tumors)
Monday, February 28, 2011 9:30 AM
Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 194, Monday Morning