Characterizing cutaneous elastic fibers by eosin fluorescence detected by fluorescence microscopy.

BACKGROUND Though elastic fibers are as important as collagen fibers in interpretation of the histopathologic findings, it is impossible to observe them on the hematoxylin & eosin (H&E) stained specimen. OBJECTIVE Characterizing eosin fluorescence emitted by elastic fibers in H&E stained specimens. METHODS Normal skin tissue sections were stained in 4 different ways (unstained, hematoxylin only, eosin only, H&E) and observed under a fluorescence microscope using a FITC filter set. Fluorescent findings of 30 H&E-stained specimens showing abnormal dermal findings were compared with bright field findings of Miller's elastic stained specimen. RESULTS Strong eosin fluorescence was related to the differential binding property of eosin with elastic fibers. Hematoxylin stain quenched excessive eosin fluorescence from other tissue components and contributed to better contrast. Fluorescence microscopy of H&E-stained sections was found to be especially useful in observing mature elastic fibers in the reticular dermis. In 74% of the specimens, eosin fluorescence findings of elastic fibers in reticular dermis matched well with that of specimens with elastic fiber special stain. CONCLUSION Analysis of skin elastic fibers by fluorescence microscopy is a useful and complementary method to reveal hidden elastic fibers in H&E-stained specimens.