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Updated: Dec 27, 2025
Targeted Studies Using Serial Block Face and Focused Ion Beam Scan Electron Microscopy
Published on: August 10, 2019
Analysis of Scars and Keloids by Focused Ion Beam/Scanning Electron Microscopy: Distinguishing Between Hypertrophic
Hisashi Migita1, Hideaki Rikimaru1, Yukiko Rikimaru-Nishi
1From the Department of Plastic and Reconstructive Surgery and Maxillofacial Surgery.
Background:
Histological differentiation between hypertrophic scars (HSs) and keloids has been considered difficult. In this study, we analyzed differences in the 3-dimensional tissue architecture between HSs and keloids using focused ion beam/scanning electron microscopy (FIB/SEM).
Methods:
Five specimens each of normal skin, normotrophic scars (NSs), HSs, and keloids were investigated. Three sites in each specimen were observed by FIB/SEM tomography, resulting in an observation of 15 sites per tissue type. We identified fibroblasts and macrophages and assessed the contact ratio and the mode of intercellular contact (planar contact or point contact). The significance of differences among the 4 tissue types was determined by Fisher exact test.
Results:
In normal skin, contact between fibroblasts and macrophages was observed at all 15 sites, and the mode of contact was always planar. There was contact at 87% of the NS sites (planar: point = 80%: 7%). In HSs, contact was seen at 80% of the sites (planar: point = 20%: 60%). In keloids, contact was found at only 15% of the sites (planar: point = 7.5%: 7.5%). The intercellular contact ratio showed no significant differences among normal skin, NSs, and HSs; however, a significant difference was noted between these tissues and keloids. The intercellular contact mode also showed no significant difference between normal skin and NSs, but a significant difference between these tissues and HSs.
Conclusions:
These histopathologic findings suggest that FIB/SEM tomography is useful for distinguishing between HSs and keloids and can provide important knowledge for understanding the pathogenesis of keloids.
