Faculty Collaboration Database

Improved detection of amyloid in fat pad aspiration: an evaluation of Congo red stain by fluorescent microscopy. Diagn Cytopathol 2004 Nov;31(5):300-6

Date

10/07/2004

Pubmed ID

15468138

DOI

10.1002/dc.20131

Scopus ID

2-s2.0-7444243704 (requires institutional sign-in at Scopus site)   42 Citations

Abstract

Amyloid fat pad aspiration specimens for cases with a clinical suspicion of amyloid typically are stained with Congo red and examined by brightfield microscopy. Congophilia with apple-green birefringence by polarization microscopy (PM) is considered diagnostic for amyloid. Examination of Congo red-stained slides by fluorescent microscopy (FM) is considered by some to be a more sensitive detection method. In this study, we assessed the utility of this technique in cytopathology archival slides from abdominal fat pad aspirations previously stained with Congo red dye. Seventy-eight cases of abdominal fat pad aspirations collected during the last 5 yr and stained with the Congo red procedure were obtained from archival files. Additionally, 20 adipose tissue material slides prepared from the surgical pathology specimens were examined as controls. One representative smear was examined in each case using FM equipped with rhodamine excitation/absorption (540/570 nm) filters. Relevant clinical information was obtained in all cases. Twelve cases (15.4%) of the 78 fat pad aspiration cases were reported originally as positive by Congo red stain using polarization and apple-green birefringence as diagnostic criteria. On review, four cases were deemed unsatisfactory. By FM examination 29 of the 74 (39.2%) cases were reclassified as positive for amyloid. The results were confirmed by immunohistochemical stain for amyloid P protein and electron microscopy. A number of similar distinct fluorescence and immunohistochemical patterns were recognized in the positive cases. Minimally weak fluorescence in the adipose tissue was observed in the control cases. The use of FM in Congo red-stained fat pad smears can improve the detection of amyloid in cytology preparations.

Author List

Giorgadze TA, Shiina N, Baloch ZW, Tomaszewski JE, Gupta PK

Author

Tamara Giorgadze MD Professor in the Pathology department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Adipose Tissue
Adult
Aged
Aged, 80 and over
Amyloid
Amyloidosis
Biopsy, Needle
Coloring Agents
Congo Red
Female
Humans
Male
Microscopy, Fluorescence
Middle Aged
Reproducibility of Results
Retrospective Studies
Staining and Labeling