COMPARATIVE ULTRASTRUCTURE OF HYPERTROPHIC SCARS AND KELOIDS

  • 1 January 1984
    • journal article
    • research article
    • p. 423-431
Abstract
Fine structural analyses of 80 lesions were compared in terms of tissue organization, fibroblast cell types, microvascular structure and differences in organelle content of endothelial cells. Both lesions consistently contain nodules of collagen, which is annealed into broad sheets of fibrils. Both lesions have a predominant active fibroblast cell type, but keloids tend to have more quiescent forms. Both lesions show high levels of occluded microvessels. Comparison of numbers and magnitude of several organelles of endothelial cells suggest keloids may be more similar to mature scars than to hypertrophic scars. Thick plastic sections of keloid tissues stained with toluidine blue O show a glazing of the collagen bundles, whereas they are crisp in hypertrophic scars. When examined by transmission electron microscopy, the collagen fibrils of keloids in the glazed areas were larger, more irregular and the interfibrillar distance was less than in hypertrophic scars. The occurrence of the irregular fibrils in keloids may reflect a significant difference in terms of collagen synthesis, fusion or breakdown. The essential difference between keloids and hypertrophic scars may be in the volume of microvessels injured, and hence, the amount regenerated, the number of pericytes, fibroblasts and, consequently, the amount of collagen synthesized.

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