Ultrastructural study of cutaneous lesions in feline eosinophilic granuloma complex

Authors

  • Mar Bardagí,

    1. Departament de Medicina i Cirurgia Animals, Facultat de Veterinària, Universitat Autònoma de Barcelona, 08193, Bellaterra, Barcelona, Spain
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  • Alessandra Fondati,

    1. Departament de Medicina i Cirurgia Animals, Facultat de Veterinària, Universitat Autònoma de Barcelona, 08193, Bellaterra, Barcelona, Spain
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  • Dolors Fondevila,

    Corresponding author
    1. Departament de Medicina i Cirurgia Animals, Facultat de Veterinària, Universitat Autònoma de Barcelona, 08193, Bellaterra, Barcelona, Spain
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  • Lluís Ferrer

    1. Departament de Medicina i Cirurgia Animals, Facultat de Veterinària, Universitat Autònoma de Barcelona, 08193, Bellaterra, Barcelona, Spain
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  • This study was funded by a grant of the European Society of Veterinary Dermatology.

Dolors Fondevila, Departament de Medicina i Cirurgia Animals, Facultat de Veterinària, Universitat Autònoma de Barcelona, 08193, Bellaterra, Barcelona, Spain. E-mail: Dolors.Fondevila@uab.es

Abstract

Abstract  The purpose of this study was to investigate the ultrastructural appearance of flame figures, reported to comprise a mixture of degenerate collagen and degranulated eosinophils, in feline eosinophilic granuloma complex (EGC). Skin specimens from eight cats with EGC and from two clinically healthy cats were examined by transmission electron microscopy. Flame figures appeared to comprise ultrastructurally normal collagen fibrils separated by oedema and surrounded by large numbers of degranulating eosinophils. Longitudinal sections of collagen fibrils displayed the characteristic cross-striation of normal dermal collagen. Feline eosinophils, analogous to human eosinophils, degranulated both by cytolysis and piecemeal degranulation. The results of this study suggest that flame figures form in feline EGC due to eosinophil recruitment and degranulation, and that collagen fibres are partially disrupted but collagen fibrils are not damaged. These findings suggest that eosinophil accumulation and the release of granule contents represent the primary events in feline EGC.

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