Search

Objective: Systemic amyloidosis is a rare disorder, characterized by extracellular accumulation of Congo red positive fibrillar amyloid protein deposits that have an amorphous, eosinophilic appearance on hematoxylin-eosin stained preparations. The kidney is the most commonly affected organ by systemic amyloidosis. Congo red staining increases the positive birefringence of the weakly birefringent unstained amyloid. In this study, we investigated the potential diagnostic power of digitally reinforced birefringence of routine hematoxylin-eosin stained slides from renal biopsies. Material and Method: We reviewed 130 hematoxylin-eosin stained slides for polarization. Sixty-five new amyloidosis cases were diagnosed by renal biopsy. All renal biopsies were evaluated by light microscopy and immunofluorescence. Slides were reevaluated blindly using a microscope (Olympus BX51) that was attached polarization filters and connected to a digital camera (Olympus DP21, SAL). Deposits that showed green birefringence on hematoxylin-eosin preparations with digitalized microscopy were considered positive and the results were confirmed using Congo red. Results: Of the 65 Congo red confirmed amyloid positive biopsies, 61 showed green birefringence with hematoxylin-eosin. Of the 65 Congo-red confirmed amyloid negative biopsies, two were considered to be false positive. The sensitivity, specificity, and positive and negative predictive values were estimated as 94%, 97%, 97% and 94% respectively. Conclusion: We concluded that polarized hematoxylin-eosin sections can be used digitally as a fast and first step diagnostic method for renal amyloidosis. [ABSTRACT FROM AUTHOR]

Objective: Amyloidosis represents extracellular deposition of congophilic fibrils of similar morphology but different chemical composition. The types frequently involving the kidney are AA (serum amyloid A) and AL (light chain amyloid). Hereditary amyloidoses, which can also affect the kidney, are being described with increasing frequency. Distinguishing the type of amyloid is important because of the different treatments and outcomes. Typing of amyloidosis by immunohistochemistry (IHC) is believed to be unreliable, except for AA amyloid. We reevaluated our cases in this study to draw attention to the nonAA amyloid deposits in renal biopsies with amyloidosis. Material and Method: Renal biopsies diagnosed as amyloidosis between 1997 and 2008 were stained for amyloid A with IHC. Cases with negative amyloid A staining were included in the study. Results: We found 190 cases of renal amyloidosis (198 biopsies) during the study period. Thirty cases (33 biopsies) with negative antiAA staining were studied. Among those 30 cases with nonAA amyloidosis, secondary AL amyloidosis was due to multiple myeloma in 8 cases and plasma cell dyscrasia in 2 cases. Hereditary renal amyloidosis was suspected in some cases. Conclusion: Using amyloid A IHC on a routine basis and the clinical history are essential to diagnose AA amyloidosis. The differential diagnosis of nonAA amyloidosis may be inconclusive on IHC. The diagnostic approach should be multidisciplinary and requires careful clinical and pathological evaluation. The limitation of IHC may necessitate direct typing of the amyloid protein extracted from paraffin-embedded specimens in some cases. [ABSTRACT FROM AUTHOR]

Copyright of Turkish Journal of Pathology is the property of Turkish Journal of Pathology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Early diagnosis and classification of amyloid deposition and differentiation from other glomerular fibrillar deposits relies on routine Congo red (CR) histochemistry. Congo red fluorescence (CRF) is an alternative method based on examination of the CR-stained section by ultraviolet (UV) light. The aim of this study is to investigate the usefulness of CRF, especially when applied to frozen kidney sections. Congo red fluorescence was applied to sections of frozen kid-ney biopsies prospectively and to paraffin sections retrospectively. The findings of CRF were compared to CR staining in bright light. Prospectively, 15 cases of amyloidosis were diagnosed on frozen sections and identical CR staining was found in all of the paraffin-stained sections. There were no false positives or negatives. Retrospectively, 146 renal biopsies previously stained with CR were re-evaluated with CRF. Eighty-seven CR positive cases were confirmed by CRF, and one new case was identified. Congo red fluorescence is simple to perform and more pronounced, therefore easier to evaluate than CR in bright light. Congo red, when combined with immunohistochemistry, is still visible under UV whereas CR is masked in bright light. Although not widely used, the CRF method for detecting amyloid is simple to use with a high specificity and sensitivity, and may be applied successfully to frozen sections. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented in response to the article "A proposed histopathologic classification, scoring, and grading system for renal amyloidosis: standardization of renal amyloid biopsy report" by S. Sen and B. Sarsık in the April 2010 issue.